WO2020239873A1

WO2020239873A1 - Method and apparatus for producing a barcode in a mouldable material

Info

Publication number: WO2020239873A1
Application number: PCT/EP2020/064769
Authority: WO
Inventors: Guggi Kofod
Original assignee: Rel8 Aps
Priority date: 2019-05-28
Filing date: 2020-05-27
Publication date: 2020-12-03

Abstract

A device for creating an optically-readable marking on a surface of a product during a moulding process, has a shaping surface for the surface of the product during the moulding process, and the shaping surface includes an encoding area comprising a plurality of fields. Each field has a temperature controlling element, which is individually addressable to enable control of the temperature of the corresponding field so as to control the extent to which the topographical texture of the surface of the corresponding field is replicated in the moulded product during the moulding process.

Description

METHOD AND APPARATUS FOR PRODUCING A BARCODE IN A MOULDABLE MATERIAL

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for manufacturing products and product parts with an integrated encoding or unique encoding on their surface, in particular coding which is capable of being read by a device such as a smartphone or similarly equipped device.

The invention is particularly suited to producing mass-produced product parts with means to enable them to be uniquely identified, making it possible to trace each part during and after their use.

BACKGROUND OF THE INVENTION

In biotechnological, medical, automotive, technical, packaging, consumer, etc. applications, it is desirable to be able to link the physical product with digital information about the product. Such information could be information which is common to a large number of identical parts, such as, for example manuals, ordering information, part reference numbers, or recycling information, or could be related to the individual product, such as its manufacturing history or other relevant information about use of the product and to enable tracking the individual part during its use.

Many such products are made by mass-replication techniques such as injection moulding or extrusion coating, where each replication is similar and every part is therefore practically indistinguishable from all other parts produced in the same way.

It would be desirable to have a system where the moulded parts may be encoded during moulding without any additional processes, and even more desirable if each individual part produced could be easily identified and linked uniquely to its manufacturing conditions, use, age or other parameters, such as those important to the use or replacement of the part. It would be further desirable if this identification of each individual part were fast and did not require of expensive and specialized equipment. Moulding and forming of products or product parts are typically fast processes, where a new part is made within the mould once every few seconds, or less. If a coding solution is to be industrially relevant for making unique codes with every production cycle, the alteration of the mould configuration so as to provide a new code should be executed within this time-frame. Furthermore, in most

applications, no change of the macro-geometry is allowed.

Injection moulding is one such common production method, signified by comprising a mould into which a hot melt is injected under pressure. The mould must be strong enough to withstand the pressure (up to 2000 bar gauge) and temperature (up to 200 °C), durable enough that the cycles of pressure and temperature can be repeated many times (from 50 up to 10 million cycles), while having a high thermal conductivity so heat can be removed from the hot melt to quickly solidify it. High pressures, exacting temperature and heat control, combined with low tolerance of failure, make injection moulding demanding.

However, all moulding or forming production methods today are being pushed to the limits of technical feasibility to achieve highest efficiency in production and highest quality in products. A successful method for serialization relying on a device to be incorporated in the tool must combine durability with miniaturization, speed and considerations of broad applicability.

US 20050115955 A1 [Refl] describes an array of microheaters embedded in a steel part, serving as one part of a moulding tool. The purpose of each individual microheater is to provide a constant source of localized heating, each electrical microheater capable of supplying a different heat load. Accurately adjusting the heat load of individual microheaters helps to avoid overall warpage of the part, while also ensuring full replication of smaller geometrical features in the mould.

US 20150224695 A1 [Ref2] describes an improvement upon this concept for injection moulding of very accurately defined geometrical features in the mould. The improved device contains thermally insulating elements in the mould, disposed between individual microheaters. The insulation improves mould operation. A skin covers the array of microheaters and insulators, to form a moulding surface. Each microheater will supply substantially the same operation for every moulding cycle, without substantial variation between individual mouldings, in order to ensure constant quality of the moulded parts.

WO 2009084762 A1 [Ref3] describes a means to rapidly heat and cool an entire tool for injection moulding, requiring also several temperature sensors in the tool. The purpose is to raise the entire mould temperature to a temperature closer to the melting point of polymer, to promote replication of all geometrical features, while the availability of rapid cooling shortens the production cycle time. This approach is generally known as "variothermic" moulding, having the benefit of improving moulding of complex geometries, but at the cost of extending mould cycling time and therefore reducing throughput. In general, "cold mould = constant mould temperature" action is desired, as this method is known generally to provide the shortest and most economical method of moulding.

EP 3159131 A1 [Ref4] describes an electrically controlled thermal matrix for integration with a moulding or forming tool for a moulding or forming process, comprising a surface topography on a body, but does not disclose any details regarding how to integrate the electrical heating elements.

US 20160070999 A1 [Ref5] describes a method of producing a code on a product during a moulding process by rotating a cylinder having anisotropic surface structures and thereby exploiting optical anisotropy to achieve individualized markings on serially produced parts. The approach is a mechanical dynamical method that does not impact moulding parameters including moulding cycle time.

J. Micromech. Microeng. 25 (2015) 035018 (Thor Christian Hobaek, Maria

Matschuk, Jan Kafka, Henrik J Pranov, and Niels B Larsen "Hydrogen

silsesquioxane mold coatings for improved replication of nanopatterns by injection molding" [ Ref6] discusses the replication of nanosized pillars in cyclic olefin copolymers by injection molding using nanostructured thermally cured hydrogen silsesquioxane (HSQ) ceramic coatings on stainless steel mold inserts with mold nanostructures produced by an embossing process.

"Processes for Nanostructuring of Plastic Parts for Biological and Optical

Applications," Henrik J Pranov, Ph.D. Thesis, Department of Management

Engineering, Technical University of Denmark [Ref7] describes various

nanomoulding experiments, whereby Nickel mould shims with bi-modal topographical structures having 1000 nm square pillars at similar height above a base height plateau were used for regular injection moulding and compression injection moulding, showing the very large influence mould temperature has on replication depth. Comprising a coating of 2 nm thick layer of fluorocarbonsilane would reduce the surface energy and shift replication ability to higher mould temperature. Also described are experiments where a planar nickel shim was coated by 220 nm layer of Fox (a silsesquioxane liquid precursor for amorphous quartz) then transformed by means of scanning electron microscopy and etching into 220 nm square pillars with side lengths from 310 to 3100 nm - this had the effect of strongly improving replication ability at lower mould temperatures. The observations are ascribed to surface tension which correlates with improved replication, while the difference in thermal effusivity (ability of material to absorb or release thermal energy) between nickel and amorphous quartz explains the difference in replication depth at similar mould temperature. In different terms, when a polymer melt flows over the topographical textures of a shaping surface of a moulding tool, the ability of the polymer melt to flow into the topographical texture in order to replicate it depends upon three factors primarily: the temperature, the surface tension and the thermal effusivity. The thermal effusivity effect is a factor at all length scales, while surface tension primarily impacts nanometer-sized features. As such, affecting both surface tension and surface effusivity of nano-to-low-micrometer sized features of a mould surface can modify the replication depth in the moulded part of the same features to predictable degree, and therefore shift the temperature window at which the effect is operational for a given polymer.

The effects are expected to be most pronounced for a hole-like topography on the shaping surface, whereas for linear trench-like structures the effect will also depend upon whether features are perpendicular or parallel to the flow direction of the injected polymer melt. In simplified terms, the quartz nanostructures have a lower effusivity and thus reduced ability to extract heat from the polymer melt, allowing for the melt to flow deeper into the topographical structures. This observation also forms one component of the invention disclosed in

W02012000500 A1 [Ref8], relying on a quartz coating having low thermal effusivity on a steel tool having high thermal effusivity. This combination allows steel parts to provide durability while the nanostructured quartz allows lower mould temperature. Other coatings exist having lower effusivity, including diamond-like carbon (DLC), nitrides, silicon carbides, etc., which when thin and having suitable nanostructures will provide similar advantageous process properties. OBJECT OF THE INVENTION

It is an object of the present invention is to provide an electrically addressable control of the local temperature distribution of an encoding surface in a moulding or forming tool, providing thereby a localized control of the replication depth of topographical textures on the encoding surface, which can then be interpreted as a machine-readable 2D barcode.

It is an object of the invention to provide a mould or mould insert in which electrically addressable control of the local temperature distribution of a part of a shaping surface is provided, wherein the mould or mould insert is able to withstand the mechanical and thermal stresses of a repeated moulding process.

It is an object of the invention to provide a mould or mould insert in which electrically addressable control of the local temperature distribution of a part of a shaping surface is provided, wherein the mould or mould insert allows a fast cycle time for the moulding process.

It is an object of the invention to provide a mould or mould insert in which electrically addressable control of the local temperature distribution of a part of a shaping surface is provided, wherein the size of the part of the shaping surface (the encoding area) is small, such as below 30 mm x 30 mm .

The advantages of this approach may include:

- avoidance of more cumbersome equipment to be engaged after part has been moulded ;

- absence of foreign contaminating materials such as labels;

- absence of impact on mould cycling time and other validated parameters;

- simplicity in control ;

- durability of the device;

- broad applicability of the method to many types of processes;

- the produced parts may comprise machine-readable barcodes that may be provided along standardized encoding and decoding algorithms.

SUMMARY OF THE INVENTION

Ref 1 and Ref 2 describe means of improving the replication of local fine features in a mould, while avoiding warpage. These means aim to provide high value components where each is identical. These documents teach that thermal insulation between the heating elements is necessary in order to achieve that aim. The present inventors have realized that provision of thermal insulation between the heating elements and/or between the fields in the surface material is not necessary, and indeed is detrimental, in the present invention. Provision of thermal insulation between the elements and/or between the fields in the surface material increases the time taken to dissipate the heat of the melt in the mould, and thus increases the cycle time, which is not economically desirable. Further, there is no suggestion in these documents that variation in the surface

temperature of different areas of a mould could have any application in changing the topographical replication of the mould surface in individual moulded items such that the moulded items can be distinguished from one another. Instead, the purpose of the variation in temperature of different parts of the mould in these documents is to ensure that the mould is evenly filled with melt, and to reduce stress during the moulding process where the part to be moulded has a complex shape or has sections of large thickness and sections of lesser thickness.

Ref 3 discloses means for rapidly heating and cooling an entire mould with an array of heating elements and cooling elements for the purpose of high control of vario-thermic moulding. There are no provisions for controlling accurate

replication of topographical texture at the nanometer and low micrometer scale, which are essential to the function of our disclosure.

Ref 4 describes a mould in which individually controllable heating elements, preferably in the form of a matrix, are provided in or below the surface of the mould in order to generate a marking such as a QR code on the moulded item by variation of the topographical replication of the surface structures of the mould. A low wear coating can be applied to the shaping surface. Ohmic conductors may be used as the heating elements. The heating elements can be provided on a PCB stack. However, the reference provides no detail as to the particular technical means for providing the desired outcome. In particular, the reference does not address the determining influence of surface energy and of thermal effusivity of the topographical features, which the present inventors have found to be of great importance in the practical design of moulds. Further, Ref 4 does not describe any practical means of localized heating, capable of operating at the small scales required for broad implementation. Finally, Ref 4 fails to describe a means for achieving a durable device that will operate for an adequate number of moulding cycles at typical moulding pressures above 50 MPa.

The present inventors have found that the design of the device, especially with respect to the provision of the heating element and the electrical connections, is crucial to obtaining a device that is capable of withstanding commercial moulding processes in terms of the mechanical and thermal stresses repeatedly made on the mould during repeated moulding cycles. Further, in order to obtain a mould in which the replication of fine detail can be varied accurately from cycle to cycle, but the cycle speed is maintained as high as is needed for commercially

acceptable operation, careful consideration needs to be given to the thermal properties of the device elements.

Accordingly, in a first aspect, the present invention provides an insert for a moulding tool having a plurality of shaping areas used for a moulding or forming process, the insert being adapted to create a machine-readable marking on a surface of a product during the moulding or forming process,

wherein the insert comprises a shaping surface including an encoding area, wherein the encoding area comprises:

- a first body comprising a topographical texture on a first side,

- a plurality of printed circuit board layers comprising metallic interconnects, landing pads and vias,

- a plurality of surface mount resistors, the plurality of surface mount

resistors providing a plurality of temperature controlling elements each capable of heating a localized region of the encoding area,

wherein the plurality of surface mount resistors is located proximate to a second side of the first body and is disposed on a first side of the said plurality of printed circuit board layers.

Preferably, the insert comprises fields in the encoding area of the shaping surface that are configured so as to produce a machine-readable marking which is in the form of an optically readable code. Preferably, the said field has an area of from 0.1 mm² to 100 mm².

The shaping surface is adapted for forming at least a portion of a surface of the product during said moulding or forming process. Preferably, the first side of the first body of the insert comprises a first surface material comprising the topographical texture. Preferably, the first surface material of the encoding area has an average thickness from 0.010 micrometer to 10.0 micrometer. Preferably, the topographical texture on the encoding area is disposed on a fraction of the area of the shaping surface of from 25% to 100%. Preferably, the topographical texture comprises surface structures characterized by having elevated areas, the said elevated areas surrounded by non-elevated areas having an average depth of from 0.025 micrometer to 25 micrometer.

Preferably, the said topographical texture on the said shaping surface comprises a plurality of elevated areas interspersed by a plurality of depressions. Preferably, the said elevated areas have a surface fraction from 20% to 95%. Preferably, the said depressions have a mean depth below the elevated areas in a range from from 25 nm to 25 micrometer. Preferably, the said plurality of depressions have depths relative to a running mean with sampling length of 100 pm characterized by having an arithmetic mean deviation of from 15 nanometer to 15 micrometer.

Suitably, the said plurality of depressions may be a plurality of holes. Preferably, the plurality of holes have openings which may be characterized by being substantially square, rectangular, diamond-shaped, round, elliptical, pentagonal, hexagonal, heptagonal, octagonal, or a mixture thereof. Preferably, the surface area of the said openings is preferably from 2500 nm² to 100 pm². Preferably, the mean separation between the rim of a first hole and that of a nearest neighbouring hole is preferably from 25 nanometer to 25 micrometer.

Suitably, the said plurality of depressions is a plurality of trenches. Preferably, the trenches have openings which may be characterized by being substantially elongated or wavy elongated rectangles. Preferably, the said rectangles have a short axis length across the said trench of from 100 nm to 3 micrometer, and a long axis length along the said trench of from 5 micrometer up to and including the entire width of the said encoding area.

Preferably, the said topographical texture is produced by a surface processing step selected from the group consisting of: lithography, masking, etching, blasting with a blasting medium, grinding, sanding, polishing, lapping, laser machining, laser engraving, anodic oxidation, electro-plating, electro-polishing, sol-gel processes, embossing, imprinting, nanoimprint lithography, curing, sintering, sputtering, etching, dry reactive ion etching, scribing, ruling, tapping and any combination thereof.

Preferably, the insert comprises one or more materials produced by means of simple or multi-material 3D printing.

Preferably, the encoding area comprises a first surface material having a thermal effusivity below 2500 Ws ⁵/(m²K). This is found to be advantageous in obtaining good replication of the topographical texture of the encoding area, particularly where the texture is in the form of nanostructures, and allows less heating of the encoding area to achieve replication of the topographical texture than would be needed for a surface material having higher thermal effusivity. Suitable materials having this thermal effusivity requirement include HSQ (hydrogen silsesquioxane), Diamond Like Carbon (DLC), Titanium Carbide (TC), Titanium Nitride (TiN), Titanium Carbonitride (TiCN), Titanium Aluminium Nitride (TΪAINΪ2), Boron Carbide (BC), Chromium Nitride (CrN), Chromium Carbide (CrC), and comparable ceramic coatings. Typically, these materials are applied to a surface using vapour deposition, sometimes with plasma assistance. The present inventors have recognised that the use of HSQ has the advantage that this can be applied in the solution phase without the use of vapour deposition techniques. Further, use of HSQ allows the use of molecular layers for reduction of surface energy or tension as described below.

Preferably, the first body is metallic. Preferably, the first body has a thermal effusivity above 7000 Ws°-⁵/(m²K). The first body does not include thermally insulating materials. The first body advantageously has high thermal effusivity in order that the heat of the melt to be moulded or formed is dissipated rapidly, allowing rapid cooling and setting of the moulded or formed article and thus a rapid cycle time for successive moulding processes. Suitable materials having this thermal effusivity include steel, aluminium, copper, brass, copper beryllium, and other metal alloys.

Where, in a particularly preferred embodiment, the encoding area comprises a first surface material having a thermal effusivity below 2500 Ws°-⁵/(m²K) and the first body has a thermal effusivity above 7000 Ws°-⁵/(m²K), it has been found by the present inventors that one can achieve high replication of the topographical texture of the surface material without excessive heating, while also maintaining the rapid heat dissipation necessary to operate at cycle speeds necessary for commercial moulding or forming operations for production of high volumes of articles.

Preferably, the insert further comprises a thermally conductive, but electrically insulating, material filling a volume disposed between said temperature controlling elements, said first side of the said plurality of printed circuit board layers and the said second side of the said first body. This has been found by the present inventors to improve the ability of the insert to withstand the mechanical stresses of repeated moulding or forming cycles, and to improve the ability of the insert to dissipate heat, to allow for fast cycles.

Preferably, the said plurality of printed circuit board layers comprises:

- a first plurality of flexible printed circuit board layers, and

- an optional further plurality of non-flexible printed circuit board layers; wherein a first portion of the said plurality of printed circuit board layers is arranged in a stack, and

wherein one or more of the flexible printed circuit board layers of the said first plurality of flexible circuit board layers extend beyond the encoding area, thereby forming a flexible wire comprising a plurality of metallic interconnects, said flexible wire disposed to the side of the insert and leading or bending in a direction away from, or opposite to, the said shaping surface of the said encoding area, and said flexible wire comprising a connector;

wherein said plurality of printed circuit board layers are supported mechanically by a support body. Preferably, the support body is metallic.

Preferably, a portion of the said plurality of printed circuit layers is sandwiched between the said first body and the said support body, said portion comprising a plurality of perforating holes passing through the plurality of layers, and said support body comprises a plurality of support pillars, said support pillars extending from the surface of the said support body so as to engage with and extend through one or more of the perforating holes. This arrangement allows the transmission of at least a part of the mechanical load from the moulding process acting upon the surface of the encoding area through the support pillars to the said support body, thus improving the mechanical stability of the insert to repeated moulding or forming operations. Preferably, the first body and the support body are metallic and/or have a thermal effusivity above 7000 Ws°-⁵/(m²K); in this case the arrangement also allows improved thermal dissipation of the heat of the melt during moulding or forming throughout the first body and support body, allowing faster cycle times.

Preferably, the first body is in the shape of a sheet has a thickness between 0.050 mm and 2.000 mm.

Preferably, the first body in the shape of a sheet has a first thermal effusivity above 7000 Ws°-⁵/(m²K). Preferably, the first body further comprises a plurality of material layers including a first surface material on the said first side of the first body having a thermal effusivity below 2500 Ws°-⁵/(m²K).

Preferably, the plurality of printed circuit board layers comprises a portion of non- flexible PCB layers, of which at least the layer on the shaping surface side of the plurality in use comprises a plurality of pillars or ridges which engage with and extend into corresponding receiving holes formed in the second side of the first body. Suitably, the form of the pillars or ridges may be cuboid, cylindrical, two or more cylinders on top of cuboids, two or more cylinders joined by boxes, or substantial variations or combinations thereof. This arrangement allows the transmission of at least a part of the mechanical load from the moulding process acting upon the surface of the encoding area through the support pillars to the said support body, thus improving the mechanical stability of the insert to repeated moulding or forming operations. The form of the pillars or ridges and corresponding holes may thus be designed specifically for maximum mechanical strength and durability under the challenging conditions posed by moulding or forming.

Preferably, the pillars or ridges comprise vias for electrical connection to one or more SMDs, provided at the first side of the plurality of PCB layers, preferably at the top (first side of the plurality of PCB layers) of each pillar or ridge.

Suitably, the SMDs are soldered to landing pads provided on the top (first side of the plurality of PCB layers) of each pillar or ridge. Preferably, the corresponding holes are blind channels, and preferably comprise at their blind ends thermally conductive but electrically insulating material, such as epoxy or potting material, surrounding the one or more SMDs provided on each pillar or ridge of the plurality of PCB layers. This allows for good thermal connection between the SMDs and the bottom of the blind channels against which they are disposed, improving the ability of the SMDs to heat up the volume of the first body and topographical texture immediately adjacent to each individual SMD.

Preferably, the said plurality of printed circuit board layers comprises a plurality of flexible printed circuit board layers. Preferably, the plurality of flexible printed circuit board layers is provided with landing pads on a first surface for soldering of an array of SMDs. Preferably, the plurality of flexible printed circuit board layers comprises a plurality of holes through all layers of the plurality of flexible printed circuit board layers, and the first body comprises cooperating pillars or ridges to engage with and extend into the plurality of holes. This allows the pillars or ridges of the first body to penetrate the PCB layers and to receive the load from the first body, comprising the shaping surface, to transfer it to the support body, below the flex-PCB. Alternatively, the plurality of flexible printed circuit board layers comprises a plurality of holes through all layers of the plurality of flexible printed circuit board layers, and thermally conductive and/or mechanically rigid rods are provided within the holes to connect the first body and the support body thermally and/or mechanically. The rods may be in the form of vias. Suitably, any voids between the plurality of flexible printed circuit board layers and the first body can be filled with thermally conductive but electrically insulating material, such as epoxy or potting material. Preferably, the first body is in the shape of a sheet has a thickness between 0.050 mm and 2.000 mm. Preferably, the first body in the shape of a sheet has a first thermal effusivity above 7000

Ws°-⁵/(m²K). Preferably, the first body further comprises a plurality of material layers including a first surface material on the said first side of the first body having a thermal effusivity below 2500 Ws°-⁵/(m²K). The plurality of material layers including a first surface material may suitably include one or more adhesive layers for bonding the first surface material to the first body. Preferably, the first body is metallic. Preferably, the support body is metallic.

Preferably, the said plurality of printed circuit board layers comprises a plurality of flexible printed circuit board layers, and the plurality of flex-PCB layers is placed in a receiving cavity of the first body, or formed between the first body and the support body. The plurality of flex-PCB layers is arranged to fit tightly or snugly in this cavity, so that the walls of the cavity may contain any motion and distention experienced by the flex-PCB during the moulding cycle. This will reduce wear due to fatigue. In this embodiment, the first body and support body may be made as a single component. The plurality of flex-PCB layers can provide an extension to serve as a flexible wire, providing a practical solution to the problem of connecting external control units to the heating matrix. Preferably, the plurality of flexible printed circuit board layers comprises a plurality of holes through all layers of the plurality of flexible printed circuit board layers, and thermally conductive and/or mechanically rigid rods are provided within the holes to connect the first body and the support body thermally and/or mechanically. The rods may be in the form of vias. The rods may preferably be metallic. Preferably, the plurality of flex-PCB layers is surrounded in the receiving cavity by thermally conductive but electrically insulating material, such as epoxy or potting material. Preferably, the first body is in the shape of a sheet has a thickness between 0.050 mm and 2.000 mm. Preferably, the first body in the shape of a sheet has a first thermal effusivity above 7000 Ws°-⁵/(m²K). Preferably, the first body further comprises a plurality of material layers including a first surface material on the said first side of the first body having a thermal effusivity below 2500

Ws°-⁵/(m²K). Preferably, the first body is metallic. Preferably, the support body is metallic.

Suitably, the heating elements, which may be switchable, may be arranged in an array such as but not limited to periodic configurations such as a linear, square, rectangular, triangular, or hexagonal array, or may be semi-randomized or randomized configurations, or any combination thereof.

Suitably, the first body or support body, or any surrounding structural element, may comprise cooling channels.

In a second aspect, the present invention provides a moulding or forming tool for creating a moulded or formed product or a series of moulded or formed products characterized by having a machine-readable marking on a surface thereof, wherein the mould comprises an insert according to the first aspect of the invention. Preferably, the moulding or forming tool comprises a plurality of shaping areas surrounding the said encoding area of the said insert, said plurality of shaping areas forming a total shaping area, said total shaping area

characterized by having a thermal effusivity above 7000 Ws ⁵/(m²K) on from 50% to 100% of the total shaping area.

In a third aspect, the present invention provides a moulding or forming system comprising a moulding or forming tool according to the second aspect of the invention, or an insert according to the first aspect of the invention, and further comprising a controlling board connected to the metallic interconnects of the plurality of printed circuit board layers of the insert, the controlling board comprising:

- preferably, a plurality of digital inputs and outputs,

- preferably, a plurality of sensor circuits,

- a plurality of individually addressable power outputs for the purpose of providing said temperature controlling elements with electrical energy,

- preferably, a plurality of central processing units providing storage and processing capability for controlling the said temperature controlling elements to express said information, and

- preferably, a plurality of communication circuits.

In any of the first to third aspects of the invention, the shaping surface may optionally further comprise one or more covalently bonded molecular layers, which have the function of reducing the surface energy or tension, in order to assist with release of the product from the mould. Typically, the layer is just one molecular layer thick. The layer is chosen with reference to the mould material and the moulding material to be released therefrom. Suitably, the shaping surface may also further comprise one or more ionically-bonded metal oxide layers, again having the function of reducing the surface energy or tension.

Suitably, the ionically bonded metal oxide layers are selected from the group consisting of: quartz, amorphous quartz, aluminium oxide, nickel oxide, nickel alloy oxide, steel oxide, vanadium oxide, chromium oxide, titanium dioxide, silicon dioxide, and any allotrope, alloy, mixture or combination thereof. Suitably, the covalently bonded molecular layer or layers may be surface reactive molecules or coupling agents, preferably including but not limited to those molecules providing silane, orthotitanate, thiol or zirconium based surface coupling reactions.

Preferably, the said surface reactive molecule or coupling agent is selected from the group consisting of perfluorododecyl trichlorosilane, perfluorododecyl trimethoxysilane, perfluorododecyl triethoxysilane, chloro-, methoxy or ethoxy- silanes with suitable pendant groups, titanium alkoxides with suitable pendant groups, zirconium alkoxides with suitable pendant groups, alkane thiols with suitable perfluorinated or other pendant groups, or other such reactive molecule or agent capable of permanently altering the surface energy of the said shaping surface.

In a fourth aspect, the present invention provides a method for creating a moulded or formed product or a series of moulded or formed products, the products having a machine-readable marking on a surface thereof, the method comprising :

- forming at least the surface of the product by a moulding or forming

process in which a moulding material is caused to contact a shaping surface, wherein the shaping surface includes an encoding area, wherein the said encoding area comprises a plurality of fields, each field including a temperature controlling element, and each field being individually addressable to enable control of the temperature of the said field in the encoding area in such a manner as to control the extent to which the topographical texture of the surface of the said field is replicated in the moulded or formed product during the moulding or forming process, and

- controlling the temperature of individual fields within the encoding area during the moulding process so as to produce on the surface of the moulded product a pattern corresponding to the said machine-readable marking;

wherein the encoding area comprises:

- a first body comprising a topographical texture on a first side,

- a plurality of surface mount resistors, the plurality of surface mount

Preferably, the fields are configured so as to produce a machine-readable marking which is in the form of a machine-readable code. Preferably, the shaping surface comprises an insert according to the first aspect of the invention, or is provided by the moulding or forming tool according to the second aspect of the invention. Preferably, the method uses a system according to the third aspect of the invention.

Preferably, the said differences in replication of the topographical texture encode digital information, which is readable by a device comprising at least one light source and one imaging system for detection of replicated and non-replicated areas in said encoding area of the said moulded part.

Preferably, the said moulding material is selected from a thermoplastic polymer, a thermoset polymer, a polymer composite, a polymer precursor, a crosslinking elastomer, a polymer film, a metal, a metal alloy, a ceramic, a ceramic precursor, a composite, a molten metal, and a molten alloy.

Preferably, the said forming is carried out by a method selected from injection moulding, variotherm injection moulding, blow moulding, casting, compression injection moulding, roll-to-roll extrusion coating, thermoforming, vacuum forming, gas assist moulding, vacuum assist moulding, film insert moulding, structural foam moulding, investment casting, roll-to-roll extrusion casting, calendaring, stamping, embossing and hot embossing.

Preferably, the method further comprises the step of changing the configuration of individually addressable heating elements to a new chosen configuration between each cycle of production.

Preferably, the topographical texture comprises a plurality of depressions, and the said plurality of depressions of the said topographical texture are at least partially replicated in the surface of a moulded part during a first moulding process characterized by a first temperature of a first field of the said shaping surface. Preferably, where the first field is not heated, the replications of the depressions have heights above the replication of the elevated area of from 0 nanometer (the ideal situation where the first field is not heated) up to a small fraction of the structure depth in fields which are heated, for example up to 50 nanometer where the structure depth below the elevated areas in a heated field is 25 micrometer. Where the first field is heated during replication, the height of the replications of the depressions will be much higher. Preferably, the said depressions of the said topographical texture are replicated with an increased aspect ratio in the surface of a moulded part during a preceding or following moulding process characterized by a second temperature of the said first field of the said shaping surface, in which the said second temperature is raised by from 10°C to 100°C above the said first temperature. Preferably the said increase in aspect ratio is from 1 to 5000 times. That is, the method preferably further comprises a second moulding process according to the fourth aspect of the invention, wherein the said plurality of depressions of the said topographical texture are at least partially replicated in the surface of a second moulded product during the second moulding process characterized by a second temperature of a first field of the said shaping surface, the said depressions of the said topographical texture are replicated with a first aspect ratio in the surface of the first moulded product, and with a second aspect ratio in the surface of the second moulded product, wherein the second

temperature of the said first field of the said shaping surface in the second moulding process is different from the first temperature of the said first field of the said shaping surface in the first moulding process by from 10°C to 100°C, and preferably wherein the said increase in aspect ratio is from 1 to 5000 times.

Preferably, in any aspect of the invention, the said machine-readable code represents information selected from a digital address, a database entry, a serial number, a model number, an internet hyperlink, and internet hyperlink address, a list of consecutive numbers, a list of randomized numbers, a list of clustered numbers, and a traceable code.

DESCRIPTION OF THE INVENTION

The present invention relates to a device for creating a machine-readable marking on a surface of a product during a moulding process, the said device having a shaping surface for forming at least a portion of a surface of the product during said moulding process, wherein the shaping surface of the said device includes an encoding area, wherein the said encoding area comprises a first body comprising a first surface material comprising a topographical texture. Preferably, the said encoding area comprises a plurality of fields, each field comprising a temperature controlling element, and each temperature controlling element being individually addressable to enable control of the temperature of the corresponding said field in the encoding area in such a manner as to control the extent to which the said topographical texture of the said first surface material of the said field is replicated in the product during the moulding process.

It is particularly preferred that the fields are configured so that the optically- readable marking is in the form of a machine-readable code.

The present invention further relates to a method for creating a moulded product having a optically-readable marking on a surface thereof, comprising forming at least the said surface of the product by a moulding process in which a moulding material is caused to contact a shaping surface [Figure 1], wherein the shaping surface includes an encoding area. Preferably, the said encoding area comprises a plurality of fields, each field including a temperature controlling element, and each field being individually addressable to enable control of the temperature of the said field in the encoding area in such a manner as to control the extent to which the topographical texture of the surface of the said field is replicated in the moulded product during the moulding process, and controlling the temperature of individual fields within the encoding area during the moulding process so as produce on the surface of the moulded product a pattern corresponding to the said optically-readable marking. The method preferably utilises the device or mould as described above.

We have discovered that surprisingly high contrast in the pattern created on the moulded product can be obtained by choice of appropriate heating temperatures combined with appropriate choice of the topographical surface texture of the field areas of the shaping surface [Figure 2], such that reading of a resulting coded pattern can be satisfactorily achieved even by consumer devices such as smartphones.

In accordance with the method of the invention surface structures may be produced on the moulded product which reflect light depending upon their topographical texture. It is possible to control the topographical texture during a moulding step using locally heating fields - the ability to control local heating to within a few millimetres has been demonstrated in [Figure 3]. The amount of local heating affects the replication fidelity of the topographical texture of the fields onto the moulded product so that the resulting area of the moulded product displays an area with fields corresponding to the heated fields of the encoding area of the encoder. The resulting code which may be interpreted as, for example an internet link, e.g. using the industry standard QR-code interpretation. The present invention relates to a device for creating a machine-readable marking on a surface of a product during a moulding process, the said device having a shaping surface for forming at least a portion of a surface of the product during said moulding process, wherein the shaping surface of the said device includes an encoding area, wherein the said encoding area comprises a first body comprising a first surface material comprising a topographical texture, said first surface material preferably having a first thermal effusivity below 2500 Ws ⁵/(m²K), and preferably wherein the said encoding area comprises a plurality of fields, each field comprising a temperature controlling element, and each temperature controlling element being individually addressable to enable control of the temperature of the corresponding said field in the encoding area in such a manner as to control the extent to which the said topographical texture of the said first surface material of the said field is replicated in the product during the moulding process.

A further aspect of the invention relates to a mould for creating a moulded product having a optically-readable or machine-readable marking on a surface thereof, wherein the mould comprises a device as described above, and wherein the said first surface material of the encoding area has an average thickness from 0.010 micrometer to 10.0 micrometer.

A further aspect of the invention relates to the said device, wherein the said topographical texture on the said encoding area is disposed on a fraction of the area of the said shaping surface of from 25% to 100%.

A further aspect of the invention relates to the said device, wherein the said topographical texture comprises surface structures characterized by having elevated areas, the said elevated areas surrounded by non-elevated areas having an average depth of from 0.025 micrometer to 25 micrometer.

A further aspect of the invention provides the said device, wherein the

temperature control elements are surface mount resistors (SMD resistors).

A particular embodiment of the invention provides a device for creating a machine-readable marking on a surface of a product during a moulding process, said device provided as an insert for a moulding tool having a plurality of shaping areas used for said moulding process, the said device having a shaping surface for forming at least a portion of a surface of the product during said moulding process, wherein the shaping surface of the said device includes an encoding area, wherein the said encoding area comprises a body formed of a metallic material, a plurality of blind channels formed in the body, the channels extending from a first side of the body to a position proximate a second side of the body opposite the said first side, a resistive heating element contained within each channel, each said resistive heating element having a heating end positioned proximate the said first side of the body, and capable of heating a localized region of the said second side of the body; and a second end extending out of the channel in the region of the second side of the body for providing an electrical connection to the respective said heating element.

According to the method of the invention, a change of temperature (general, local heating of a small field in a mould within an encoding area changes its ability to transfer its topographical texture (also known as surface structure) to a material being moulded or formed. In this fashion, it is possible to directly and simply control the surface texture on the moulded or formed part, by controlling the surface temperature of the mould in the relevant localised area or "field", thereby causing a modification of its optical appearance or other surface property in that area with respect to other parts moulded from the same mould .

It may be advantageous in some cases and for some encoding standards to address several of the fields with an identical signal, hard-wired in the layout of the connecting wires, such as to reduce the number of active control channels. An example is the L-frame and timing pattern in the GS-1 Datamatrix encoding standard, where these features remain constant for every moulding cycle, and therefore do not require addressability to provide the desired function.

The topographical textures on the fields within the encoding area can be produced by various manufacturing or machining methods, including blasting, sanding, polishing, vacuum coating, coating or painting with a composite material, drilling, machining, scribing, lithographical methods including electron and

photolithography, texturing and plasma and chemical etching methods. The particular method by which the structure is produced is of lesser importance, while the topographical characteristics are of higher importance. The resulting textures are commonly defined by statistical means such as surface roughness Ra, area roughness Sa, total peak-to-valley height Rz, to name a few. Some methods for creating structural topography are deterministic in nature, providing in some cases bi-modal height distributions, whereas other methods are statistical in nature, providing distributions in geometrical features having recognizable elevated areas (examples include the deliberate roughness introduced on the cylinder walls of a combustion engine, to provide a carrying structure for lubricating the cylinder walls).

More important for the functionality of the present device is the concept of "elevated areas," whereby is meant that a substantial fraction of the shaping surface forms a plateau, with most of the remaining part of the surface forming depressions in this plateau, having heights below the level of the plateau. These depressions may appear substantially as holes, where the characteristic hole diameter is below 10 pm such that the characteristic surface area of the hole opening is below 100 pm². The depressions may also appear substantially as trenches, to be disposed substantially perpendicularly to the expected polymer melt flow and having trench width below 10 pm.

The required depth of the holes or trenches depend upon their characteristic hole diameter or trench width, respectively, and is properly characterised by the aspect ratio, which is the ratio of the characteristic depth divided by the characteristic length. The aspect ratio of pillars or ridges formed from a given shaping surface, should be between 0.05 and 2.5 to achieve substantial optical scattering. When two neighbouring fields have been produced with different temperatures, a subsequent scanning procedure will substantially distinguish between the two by their ability to scatter optical light, which again will depend primarily upon the aspect ratio - hence, detection of whether a field is meant to be "black" or "white" comes down to differences in aspect ratios. The detection limit depends strongly upon the quality of light in the surroundings, the quality and specifications of the camera and its optical lenses, and upon the analytical software deployed.

The aspect ratio of the holes or trenches should at least encompass the aspect ratios desired to achieve detection. As an example, an un-heated field having holes of diameter 1 micrometer and depth 2 micrometer gives rise to pillars replicated in the moulded part having heights of about 5 nm. A neighbouring heated field comprising holes with identical features gives rise to pillars of height of about 500 nm. This provides an increase in aspect ratio of 100 times.

Some part of the surface, including defects, may be raised above the plateau without substantially affecting the workings of the device. It is preferred that the topographical texture comprises surface structures having mean depth of from 0.1 microns to 25 microns. By a characteristic hole diameter or trench width is also meant a narrow distribution, as some statistical means of manufacturing of topographical texture will create holes or trenches with some distribution.

A mould or form is typically composed of one or more materials, typically based on the properties and prices of the materials, including the level of effort required to machine the material into the desired shape and surface property. Common mould materials include metals and alloys, and combinations thereof, in some cases also including ceramic materials in whole or in part. Most commonly used materials have high thermal conductivity. Also, most commonly used materials have high thermal effusivity, above 7000 Ws°-⁵/(m²K), providing advantageous thermal properties that lower the mould cycle time for an efficient process. High effusivity is detrimental to the workings of the disclosed device, as it causes poor moulding of small topographical textures, and therefore may interfere with the working of the device. Lower thermal effusivity below 2500 Ws°-⁵/(m²K) improves moulding of nanometer textures, and therefore places the moulding parameters for said textures within a range to be affected by localized cooling and heating.

The timing of the heating can be tuned to improve the overall process efficiency.

If each heating element (temperature controlling element) is heated to the required temperature only for a short time around when the polymer melt flow passes over the encoding area, less heat overall is provided to the mould by the device, and hence less heat must be drawn away. It is therefore advantageous to reduce the total time of heating of the fields of the encoding area to a minimum.

In a preferred embodiment, a device comprises a metallic body, coated on the surface by one or several thin material layers. The metal is typically steel, whereas one or more coatings comprise optional adhesion layers and final first surface material. The steel has high thermal effusivity, whereas the first surface material has low thermal effusivity, thereby conferring on the steel desirable thermal properties. The steel may be in any suitable shape, including a sheet or a block. The steel surface may be provided with desirable topographical texture, coated then by very thin layers of optional adhesion material and the first surface material. Or the steel may be smooth, coated then by optional adhesion materials and the first surface material, utilizing processing parameters, and optional methods or process steps that will provide a desirable topographical texture.

These are described in the following.

In a preferred embodiment, each field has an individual heating element

(temperature controlling element), and the fields are arranged in an array, for example of dots or bars, in which each dot or bar in the array defines either a bright or dark state on the product, depending upon whether it was heated or not during moulding, and represents a data bit.

The array of bright or dark states is thus able to form a 2D barcode. Readout of data from the encoded are may be carried out by conventional means, typically by optical means. In some cases such readout may require a secondary light source, for example such as may be found in in a smart-phone or a vision system.

In a preferred embodiment of the invention, the field pattern in the encoding area may be changed for each part produced in a mass-production process, so that each mass-produced part is uniquely identifiable. In a further preferred embodiment, the resulting code may be read using a smartphone. The possibility of using readily available devices with integrated data network capabilities, light source and camera, such as smartphones, makes this method industrially applicable, both for use in the industry and for consumers.

In a preferred embodiment, the present invention is able to provide a means to make a unique code on a moulded part without introducing additional process steps.

In a further preferred embodiment, the present invention provides a method for mass-producing large numbers of moulded products or parts with unique codes, so that each is individually traceable or identifiable. In a further preferred embodiment, a data-structure may be provided to couple information relevant to the individual product or part to the identifier on the said part. This coupling makes it possible to use readily available equipment, such as smartphones.

In the broadest aspect of the invention, the fields within the encoding area may represent any desired shape or element, for example individual numbers or letters. In a particularly preferred embodiment however, the fields are configured so that the optically-readable marking is in the form of a machine-readable code, such as the elements of a standard 2D barcode. In accordance with the present invention, a code may be produced on a moulded product by exploiting the difference in replication of topographical textures between surface fields different surface temperatures. The method exploits a difference in replication of topographical textures between surface fields different surface temperatures.

The method of the invention may be used with a variety of moulding methods, for example injection moulding, thermoforming, blow moulding, injection blow moulding, extrusion blow moulding, extrusion stretch blow moulding, rotation moulding, casting, embossing, and many other similar processes. In all these methods, a product is generally formed by bringing a metered amount of raw material, against a mould or form having a particular shape and topographical texture. The raw material is typically provided in a particular state, such as in the case of thermoplastic polymer, which is first melted so that it forms a liquid and is then injected into a mould, in a process commonly referred to as plastic injection moulding.

The required topographical texture, switching temperature and switching times depend strongly upon the material to be moulded. One example is injection moulding, where some polymers are typically moulded with a mould temperature of 20°C, while others may be moulded at 150°C, some even higher. A larger temperature span occurs for metals, ceramics and glass, composites and other mouldable materials.

The device or insert for integration in a mould, referred to in the description below for ease of reference as an "encoder", although the markings resulting on the moulded product may not necessarily be "encoding" in a conventional sense, are preferably made of materials that provide durability under conditions of many mould cycles. The elements of the device include [Figure 4] : a shaping surface, having relevant topographical textures; and heating elements (temperature controlling elements), providing localized heating to define heated fields; an optional cooling system, such as cooling channels may also be provided; the device suitably has a sufficient bulk to provide mechanical stability; it may also include means for fixing the encoder in a mould.

In a further preferred embodiment, the array forms a 2D "barcode" which may be represent an internet or database link to a web page displaying relevant information, using commonly used standards, such as the QR Code developed by DENSO WAVE INCORPORATED. It is to be understood that the term "barcode" as used herein is used in the general sense of a code representing data, not in the more limited sense of a code comprised of "bars".

In one embodiment, the device may comprise a body formed of a metallic material; a plurality of blind channels formed in the body, the channels extending from a first side of the body to a position proximate a second side of the body opposite the said first side; and a resistive heating element contained within each channel, each resistive heating element being elongate in shape and having a first end positioned proximate the said first of the body, and capable of heating a localized region of the said second side of the body, and a second end extending out of the channel in the region of the second side of the body for providing an electrical connection to the respective said heating element.

The body may be constructed made by drilling of an array of (for example) 10*10 holes in a block, however, avoiding fully perforating the block. Each individual hole is provided with a heat cartridge having a diameter of approx. 3 mm. Each heat cartridge can be individually activated by running a current through it, to heat a local field on the surface of the encoder. The surface of the encoder is sand-blasted using highly abrasive zirconium grit.

In a further preferred embodiment, the shaping surface is comprised of a thin plate of steel, which is etched on the shaping side using lithographical means to achieve a topographical texture. The back side of the plate may be placed on top of a cushion of individually spring-loaded pins, which touch the plate in a small area. The plate may also serve as an electrical ground. When current is passed through a pin, most of the electrical energy is dissipated in the interface between the pin head and the thin plate, thus locally heating the surroundings and surface near the pin. The relevant pins for achieving the required configuration are heated using the same current level.

In a further preferred embodiment, the encoder is printed by means of multi material 3D printing, whereby materials of differing electrical properties may be printed in a chosen spatial arrangement. The body of the device may be defined using material with high electrical resistivity, while electrical conduits are defined using low-resistive material. The heating element may be defined near the surface of the encoder using medium-resistive material. Optional cooling channels can be defined. A topographical texture may be applied to the surface of the 3D-printed block after 3D-printing has been completed.

In a further preferred embodiment, the surface of the encoder is non-planar, for example it may form a smooth single curve, for example for mounting on a roll- to-roll polymer shaping process, such as extrusion coating or casting.

Alternatively a double curved or free form curve may be employed, as well as a simple flat shape.

In a further preferred embodiment, a polymer replica, comprising optically anisotropic structures, is metalized subsequent to the moulding process, thereby increasing its contrast. The increase in contrast ensures that most wavelengths of the electromagnetic radiation spectrum from low radio frequency to visible light, will achieve adequate detection levels. In this special embodiment, the 2D binary barcode may be used as a RFID chip, detectable by radio frequency radiation, preferably in the frequency range of 1 to 100 GHz.

In a particular embodiment, the invention provides a method for creating an individually configurable barcode during serial production of products by a moulding process comprising

- a moulding material;

- an encoding area being part of the mould comprising a shaping surface;

- the said shaping surface of encoding area having a topographical texture;

- said encoding area comprising a multitude of temperature controlling elements;

- said temperature control elements being activated to control individual surface temperatures in a multitude of individual fields on the said shaping surface;

- said individual surface temperatures of individual fields on said shaping surface being controlled in such a manner that the topographical texture of a first multitude of individual fields is replicated in the product with higher replication fidelity during the said moulding process in comparison to the replication fidelity of the topographical texture replicated by a second multitude of individual field;

- a moulding process performed in such a manner that during the moulding process forming a product comprising the moulding material with a partly topographically textured area within the corresponding encoding area of the shaping surface. The invention furthermore relates to a method as described above, in which the said higher value of the said replication fidelity on the product of the replicated topographical texture from a first multitude of individual fields is higher than the said fidelity of the replicated topographical texture from a second multitude of individual fields by a relative ratio of replication fidelities of at least 1%, even more preferably of at least 2%, even more preferably of at least 5%, even more preferably of at least 10%, even more preferably of at least 25%, even more preferably of at least 50%, even more preferably of at least 100%, even more preferably of at least 200%, even more preferably of at least 500%, and most preferably of at least 1000%. The term "replication fidelity" as used herein is defined hereinafter.

The topographical texture applied to the fields of the encoding area (and replicated selectively in the surface of the moulded product) may comprise a surface structure having a light guiding functionality such as, but not limited to, diffusion, scattering, diffraction, reflection or absorption.

The invention furthermore relates to a method, whereby the said topographical texture may comprise surface structures having an average depth of from 0.1 to 25 pm, typically less than 10 pm, more preferably less than 2 pm, even more preferably less than 1 pm, even more preferably less than 500 nanometers, even more preferably less than 200 nanometers, and most preferably less than 100 nanometers.

The invention furthermore relates to a method, wherein the said topographical texture may comprise surface structures having an average depth of from 0.1 to 25 pm, typically less than 10 pm, more preferably less than 2 pm, even more preferably less than 1 pm, even more preferably less than 500 nanometers, even more preferably less than 200 nanometers, and most preferably less than 100 nanometers.

The encoding area is preferably configured so as to produce on the moulded product a code, for example a 2D barcode, which may be standardized according to an encoding and decoding scheme. The scheme may be an existing recognised and standard scheme, or a proprietary scheme, and in general may be any coding system suitable for codifying information for the purposes of enumerating, cataloguing, inventorying, serialization or simply counting individual items that are produced in serial production. Specific examples of suitable encoding systems are QR, Micro QR, Data matrix, Dotcode, Qode, Nexcode, GS1, Maxicode, EZcode, PDF417, and AZTEC. Any other encoding standard may also be suitable, including those proprietary to a particular organisation.

The differences in surface topography in the moulded product encode digital information, which may be read be a reading device comprising at least one light source and one imaging system for detection of replicated and non-replicated areas in said encoding area of the said moulded part. The reading device may be understood in broad terms as requiring only at least one light source such as an ambient light source, one image recording device and a processing unit capable of interpreting images in terms of filtering the image, identifying a coding region of theimage, filtering and analysing that portion of the image, and finally converting and extracting the encoded information.

The reading device may be a scanner, a vision system, a distributed system depending upon ambient lighting and an image recording device and a processing unit placed at a distant connection, a smartphone, a laser scanner, an x-ray scanner, a LIDAR.

The moulded material may be, but is not limited to, a thermoplastic polymer, a thermoset polymer, a metal, a metal alloy, a ceramic, a ceramic pre-cursor, a composite, a polymer precursor, crosslinking elastomer, molten metal, molten alloy, polymer film, or ceramic pre-cursor.

As indicated above, the encoding area may be flat, curved, double-curved or free form.

The size of the encoding area may vary, depending on the nature of the product being produced. For example a tractor tyre may require a large encoding area, such as 400cm² or more, whereas for a smaller product, an encoding area of less than 40 cm², less than 4 cm² or less than 0.4 cm² may be suitable. Preferably, the overall size of the encoding area can be of a smaller size, such as at least below 30 mm x 30 mm.

In a particularly preferred embodiment, the chosen configuration of individually switched heating elements have the ability to be re-configured to a new chosen configuration between each cycle of production.

Marking of products for serialization requires every part to receive an individual coding in the form of a string of numbers or letters, encoded in a practical encoding scheme. Error correction is typically included for robustness of the code in production and usage of the product. Some production setups may benefit from smaller sets of products having identical codes. Typical benefits include greater transparency of production flows, faster correction of production problems, and mitigation of counterfeit problems, among many others.

The encoder is capable of controlling the surface temperature individually in a plurality of areas within the encoding area.

The heating elements (temperature controlling elements) may be heated using resistive heating elements which are surface mount resistors (SMD resistors), heating cartridges, resistors, pin-point connections, spring-loaded pin-point connections, 3D-printed materials, resistor pastes and resistor adhesives.

Particularly preferably, the temperature controlling element is or comprises a surface mount resistor (SMD resistor).

The size of the product determines the maximum size of the code marking. A small product can typically only set aside a small fraction of the product surface for code markings. This requires attention to miniaturization of the salient features of the code, including the components and methods for manufacturing the device to provide the coding process.

One such means of miniaturization relies on the availability of small surface mount device resistors, or SMD resistors. These SMD are small rectangular

parallelepipeds, or cuboids, having a first surface coated with a thick film resistor paste or evaporated metal, serving as a well-defined resistor. Trimming can be made to adjust resistance to within 1% or less of the nominal value. Some SMD resistors serve as surge protectors, able to withstand very high currents, and thus able to function as heat elements providing 1 W or more of heat power in a small area less than 1 mm².

The topographical texture of the fields in the encoding area may be produced by various manufacturing processes, such as, but not limited to, etching, lithography, masking, blasting with a blasting medium, grinding, sanding, polishing, lapping, laser machining, anodic oxidation, electro-plating, electro-polishing, sol-gel processes, embossing, nanoimprint lithography, sputtering, dry reactive ion etching, scribing, ruling, tapping or any combination thereof. Many methods for producing topographical textures having desirable statistical or deterministic surface topography are known in mechanical engineering, and novel methods arise continuously, such as in the "NaPANIL Library of Processs," Helmut Schift (Ed.), Publ. Jouni Ahopelto, 3rd ed. (2014) ISBN 978-3-00-038372-4.

In a first aspect of the invention, a device is provided for creating a machine- readable marking on a surface of a product during a moulding process, said device provided as an insert for a moulding tool having a plurality of shaping areas used for a moulding or forming process, the said device having a shaping surface for forming at least a portion of a surface of the product during said moulding or forming process, wherein the shaping surface of the said device includes an encoding area, wherein the said encoding area comprises a first body comprising a topographical texture on a first side, further comprising a plurality of printed circuit board layers comprising metallic interconnects, landing pads and vias, further comprising a plurality of surface mount resistors providing a plurality of temperature controlling elements each capable of heating a localized region, said plurality of surface mount resistors disposed on a first side of the said plurality of printed circuit board layers, said plurality of surface mount resistors located proximate a second side of the said first body.

A printed circuit board (PCB) mechanically supports and electrically connects electronic components or electrical components using conductive tracks, pads and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. Components such as SMD resistors are generally soldered onto the PCB to both electrically connect and mechanically fasten them to it, typically by means of wave-soldering. PCBs can be single-sided (one copper layer), double-sided (two copper layers on both sides of one substrate layer), or multi-layer (outer and inner layers of copper, alternating with layers of substrate), with electrical interconnects provided by drilled holes filled with copper paste. Multi-layer PCBs allow for much higher component density, because circuit traces on the inner layers would otherwise take up surface space between components. Most PCBs are made with glass-reinforced epoxy (FR4), but can also be made with aluminium board or ceramic board. A very wide variety of methods, materials and solutions are available, see "Printed Circuits Handbook, Seventh Edition (7th ed.)," by Clyde F. Coombs, Happy Holden, McGraw-Hill Education (2016), ISBN : 9780071833967. Printed circuit boards (PCBs) provide suitable combinations of stiff glass fiber epoxy boards with flexible polyimide sheets (flex-PCB), capable of bending. The boards can be stacked and cut or milled to various shapes, easing the integration of the board or breaking of the board into smaller sub-boards. Within boards are placed various lines of copper serving as electrical wires. Wires on different boards can be joined using vias, which are columnar wires traversing one or several layers in the stack.

Thermal control is essential to most power electronics. Copper wires on PCB, including vias, are able to transmit some portion of heat. A PCB stack can integrate many types of components, including temperature and pressure sensors, which can be used for external feedback control of the encoding device.

In a further preferred embodiment a device comprises fields that are configured so as to produce a machine-readable marking, which is in the form of an optically readable code, said device provided as an insert for a moulding tool used for said moulding process, wherein the said first surface material of the encoding area has an average thickness from 0.010 micrometer to 10.0 micrometer, wherein the said topographical texture on the said encoding area is disposed on a fraction of the area of the said shaping surface of from 25% to 100%.

In a further preferred embodiment, the said topographical texture comprises surface structures characterized by having elevated areas, the said elevated areas surrounded by non-elevated areas having an average depth of from 0.025 micrometer to 25 micrometer.

In a further preferred embodiment, the said encoding area comprises a first surface material having a first thermal effusivity below 2500 Ws°-⁵/(m²K).

In a further preferred embodiment, the device comprises thermally conductive material filling a volume disposed between said resistors, said first side of the said plurality of printed circuit board layers and the said second side of the said first body. Good contact between SMD and an object to be heated, in an environment with large mechanical loads, can be achieved in the present invention by including a formable material in the assembly of a device. These are known as potting or casting materials, provided in various ways including pastes, 2-component mixtures, liquids, etc., which allows producing two components in different workflows, then joining them with maximum mechanical strength, thermal transmission and electrical insulation in a facile way. Aremco Technical Bulletin A4, rev. 4/18, titled "High temperature potting and casting materials", describes several ranges of potting and casting materials for use in heat and mechanical load management in electrical equipment. Potting or casting materials are generally low-fired ceramic or silicone-based materials, which are used for electrical insulation of electrical elements, some capable of withstanding high mechanical loads over 50 MPa, and having low or high thermal conductivity.

Masterbond Technical information regarding "Supreme 12AOHT-LO", rev. G23C14, describes a one part epoxy for thermal management, with high resistivity and high compression strength over 150 MPa. The Aremco and Masterbond materials are few of many potting and casting compounds and systems that are

implemented by simple means, and are providing thermal load management under adverse conditions, including elevated temperatures and high mechanical loads, such as in a moulding or forming tool. Such materials provide the practical advantage of enabling a strong bond between disparate materials and constructs, such that adequate transfer of heat and mechanical load for improved function and durability is provided.

In a further preferred embodiment, the said plurality of printed circuit board layers comprises a first plurality of flexible printed circuit board layers and an optional further plurality of stiff printed circuit board layers, wherein a first portion of the said plurality is arranged in a sandwich, and wherein one or more of the said flexible printed circuit board layers of the said first plurality of flexible circuit board layers extend beyond the encoding area, thereby forming a flexible wire comprising a plurality of metallic interconnects, said flexible wire disposed to the side of the device and bending in a direction opposite the said shaping surface of the said encoding area, said plurality of printed circuit board layers being supported mechanically by a further metallic support body, said flexible wire comprising a connector.

It has been found by the present inventors that flexible printed circuit board layers (Flex-PCB) can bend around smooth corners and still survive mechanical loading and un-loading over many cycles, and therefore serve also as a durable multi-stranded wire connection between an external control system and a portion of the board which is snugly integrated in a portion of a moulding or forming tool. The SMD may be mounted on the very surface of a PCB or flex-PCB stack, allowing for direct electrical control of individual SMD from an external control system. The multi-stranded flex-PCB wire may extend away from this critical region of the insert, and be provided with a connector block for simple connection to the control system using a suitable mating connector.

In a further preferred embodiment, a portion of the said printed circuit layers is sandwiched between the said first metallic body and the said support body, said portion of printed circuit board layers comprise a plurality of perforating holes, said support body comprising a plurality of support pillars, said support pillars distending from the surface of the said support body so as to match with one or more of the said plurality of perforating holes, so as to transmit at least a part of the mechanical load from the moulding process acting upon the surface of the encoding area through the support pillars to the said support body.

In a further preferred embodiment, the said body formed of a metallic material is in the shape of a sheet has a thickness between 0.050 mm and 2.000 mm.

In a further preferred embodiment, the said body formed of a metallic material in the shape of a sheet has a first thermal effusivity above 7000 Ws°-⁵/(m²K), whereby the said body further comprises a plurality of material layers, further comprising a first surface material on the said first side having a first thermal effusivity below 2500 Ws ⁵/(m²K).

The use of PCB allows for combinations of stiff PCB with flex-PCB. The materials can be joined in stacks, and be provided with electrical connectivity within a layer or between layers by means of vias. Both types of PCB can be machined by various means, including milling and laser cutting. PCB material can be provided in various thicknesses.

In a further preferred embodiment, the stiff PCB is milled in various geometries substantially providing a plurality of pillars. The shape of the plurality of pillars may be cuboid, cylindrical, two or more cylinders on top of cuboids, two or more cylinders joined by boxes, or substantial variations or combinations thereof - the single determining feature is the pillar-shape itself, provided to place the SMD in a receiving hole in the body, such that the body and insert may be designed specifically for maximum mechanical strength and durability under the challenging conditions posed by moulding or forming. The pillars comprise vias for electrical connection to the SMDs soldered to the landing pads on top of each pillar. The body is machined with blind channels to substantially provide a negative match to the geometry of the provided pillars. The blind channels are provided with thermal epoxy or potting material before assembly, allowing for good thermal connection between the SMDs and the bottom of the blind channels against which they are disposed. This provides an ability to heat up the volume of steel and topographical texture immediately adjacent to each individual SMD.

In a further preferred embodiment, relying for the most part on the properties of flexible PCB, or flex-PCB, a stack of such flexible boards has a suitable

connectivity and is provided with landing pads on a first surface for soldering of an array of SMD's. The flex-PCB can be perforated in the encoding area, to allow for support pillars to penetrate and receive the load from the sheet comprising the shaping surface, to transfer it to the support from the steel insert below the flex- PCB. The flex-PCB is placed in a receiving cavity of the steel insert, formed when it is assembled from several parts - the flex-PCB is machined to fit tightly or snugly in this cavity, so that the walls of the cavity may contain any motion and distention experienced by the flex-PCB during the moulding cycle. This will reduce wear due to fatigue. Also this flex-PCB can provide an extension to serve as a flexible wire with practical solution of the problem of connecting external control units to the heating matrix.

The temperature control elements may be switchable heating elements arranged in an array such as but not limited to periodic configurations such as a linear, square, rectangular, triangular, or hexagonal array, or may be semi-randomized or randomized configurations, or any combination thereof.

The temperature control elements or any support or surrounding structural element may also preferably comprise cooling channels.

The control system is connected to the device via connectors. The control system comprises power on a number of channels, each channel controlled to be substantially on or off by a processing unit, all being controlled and monitored from external inputs via input/output circuits and protocols, which may also be wireless. The power is provided by the said channels, which may also monitor the current consumption, as a means to use an individual SMD as a local temperature gauge, which in turn can be used in a feedback control loop to provide accurate heat on each field. The invention further provides a moulded product having at least two pluralities of fields within an encoding area with different replication fidelity, in particular, produced by an encoder as described herein.

In the preferred moulding process used herein, a mouldable (for example a molten, liquid or liquefied) moulding material is brought in contact with a shaping surface with a temperature below the solidification temperature of the said moulding material. Examples of this process are injection moulding, variotherm injection moulding, blow moulding, casting, compression injection moulding, roll- to-roll extrusion coating, thermoforming, vacuum forming, gas assist moulding, compression moulding, film insert moulding, structural foam moulding,

investment casting, roll-to-roll extrusion casting, calendaring, or any other production method whereby a shaping surface is brought against a material that melts or solidifies upon contact to a shaping surface and where the surface temperature of the shaping surface at least partly determines the replication fidelity of the produced part.

The term "optically-readable" should be understood to mean electromagnetic radiation both in and outside the visible spectrum.

The chosen configuration of individually switched temperature control (typically heating) elements may represent information such as, but not limited to, a digital address, a database entry, serial number, model number, or a traceable code.

In a preferred embodiment, the temperature-controlling elements may be controlled by at least one system external to the said shaping surface, and utilise any type of machine software, production software, business software, cloud database software, distributed ledger software such as a block-chain software, or any combination thereof.

By topographical texture is meant a surface topography of a surface which confers on the surface a property, e.g. a light guiding functionality which is different from that of a smooth surface of the same material.

The structure size should be interpreted depending on the context. The structure size defined in this context depends on the type of structure comprising the surface topography. In the case of deterministic structures, the repetition length is a good measure for the structure size, e.g. the period of a diffraction grating or a plasmonic structure. In the case of a random surface structure, the average peak-to-peak distance may be used, which can be found be e.g. a Fourier analysis of the topographical image.

By light guiding functionality is meant a property of a well-replicated

topographical texture, in that the textured surface interacts with light in a different manner than a flat surface. Examples of this may be the diffraction of light from a diffraction grating, absorption of specific wavelength from plasmonic surface structures, diffusion or backscattering of light from both random and controlled surface diffusors, reflection of light in specific direction be non horizontal reflectors.

By "metallic" is meant "made of a metal or metal alloy".

By moulding material is meant the material which the produced part consists of. This type of material will typically be liquid when at one temperature state and solid when at another temperature state. Or it may be initially liquid, then made solid due to a chemical or other curing process. Non-limiting examples are metals, ceramics, polymers, or composites or alloys thereof.

By shaping surface is meant the surface of the mould used in the moulding process, which the moulding material replicates. Typically both the macro geometry (the shape) and the micro-geometry (the topographical texture) will be replicated. However, especially the replication degree of the micro-geometry is dependent on the process parameters of the moulding process in general and the surface temperature of the shaping surface in particular. By having a low surface temperature, replication will in general be lower than when having a higher temperature.

By field is meant a sub-area of the encoding area defining each separately temperature controlled area, typically defining the bits of the created code or pixels in the created image.

By encoding area having a shaping surface is meant a part of the shaping surface of the mould where the replication fidelity of the surface texture is controlled by heating fields on the surface individually. This control can be through control of the surface temperature during the moulding cycle, whereby the replication fidelity of individual areas of the encoding area can be different, e.g. binary where an individual area (or bit) is either replicated or non-replicated. In practice, some degree of replication will always occur, and therefore this needs to be understood in the context of the detection method. One example could be to use a diffraction grating, where the diffraction efficiency depends strongly on the replication depth, and during detection set a threshold for the detected light intensity, where below- threshold signal corresponds to 0 and above-threshold signal corresponds to 1. Another example could be to use a plasmonic structure where the wavelength response depends strongly on the depth of the structure, where the distinction between 0 and 1 will be determined by difference in e.g. wavelength absorption spectrum (the color of the surface).

By partly topographically textured is meant a surface where the replication fidelity between the heated and non-heated elements or fields (the individual bits of the encoding area) differs significantly, such as being able to distinguish them through the readout of said reading device. Typically, a replicated area would have a replication depth of more than 20-50 nanometers and a non-replicated area would have a depth of less than 10-15 nm. The higher difference between replicated and non-replicated areas that can be achieved during the moulding process, the easier, more robust and error tolerant will the readout process be.

By replication fidelity is meant the filling ratio of the topographical texture which is replicated in the product. As an example, an individual field having a controlled first temperature which is high relative to the overall mould temperature may lead to full replication of structures having a depth in the moulded part of 500 nm, whereas an individual field having a controlled second temperature which is lower than the controlled first temperature may lead to incomplete replication of mould structures resulting in a depth of the structures in the moulded part of only 100 nm. The replication fidelity of the first area is 100%, whereas the replication fidelity of the latter is 20%, with a relative ratio of replication fidelities of 500%.

As discussed previously, a larger replication fidelity may lead to a more robust and error tolerant readout process as the contrast in the readout method will typically increase.

The term "smartphone" as used herein is intended to be understood in its usual context, and may preferably means a device which is typically capable of illuminating a part, acquiring and storing images in an internal memory, processing the images in order to convert the image to a binary barcode, calculating, for example, an internet link corresponding to this barcode, and providing direct or indirect internet or database access to retrieve information stored at this internet or database link. Non-limiting examples of smartphones are the Apple Iphone series, the Samsung Galaxy series or other devices with the same functionality as these, such as tablets or wifi / internet-capable cameras.

The term "continuous material" means a material where the bulk optical properties, such as the color or refractive index, of the material does not substantially change through the material. Examples of continuous materials are single-melt moulded polymers, bulk metals pressed or moulded into shape.

Continuous materials may have non-continuous surface optical properties caused by the surface topography of the material.

By RFID is meant a Radio Frequency IDentifier, where the 2D barcode will be detectable by frequencies of electromagnetic radiation other than visible light.

Most materials are relatively permeable to radio frequency radiation, and thus an RFID does not generally require line of sight to be identified.

By readable or detectable or similar, is meant a surface pattern which is recognizable by a reading device as specified using the value of spatial reflectance as parameter. If the spatial reflectance in a given point is above a threshold value, the point is recognized, as e.g. the digital value of 1, and if the spatial reflectance is below the threshold value, the point is recognized as e.g. the digital value of 0. The readability may be improved by data analysis means, such as machine learning or "artificial intelligence," to improve the detectability of a code, the presence of which may be difficult to detect by human eye. In this context, such a device is an electronic device, such as a smartphone or a tablet or other device featuring a camera and a light source, including laser light sources such as handheld barcode scanners. The device will preferably have processing abilities and network access to transform the image of the code into a digital entity, such as e.g. a number or text string or combination thereof, for the means of providing information relevant to a given context. By machine-readable is similarly meant information provided in such a manner that a machine (in broadly encompassing terms) may be able to scan and convert the code into processible information.

The term "light" and "optical" as used herein are meant to refer to

electromagnetic radiation, used to probe the surface of the moulded article to read the applied field pattern, in particular the applied barcode. The wavelength of the light is preferably in the range of 400-800 nm, but in special embodiments other wavelengths of electromagnetic radiation may also be used, such as radio frequency electromagnetic radiation.

All of the features described herein may be used in combination in so far as they are not incompatible.

BRIEF DESCRIPTION OF THE FIGURES

The method and apparatus according to the invention will now be described in more detail with reference to the accompanying drawings, which show only a number of preferred embodiments of the invention and should not to be construed as being limiting the scope of the invention. In the drawings: -

Figure 1 is a schematic representation of four fields of an encoding device;

Figure 2 illustrates an experimental rig demonstrating the principle of the invention;

Figure 3 shows four heat profile (FLIR) images of an encoder surface having 4 individually heated areas which can be individually operated. ;

Figure 4 is a schematic representation of a moulding apparatus with mould insert and controller;

Figures 5a to 5c are schematic cross sections of a mould insert device useful for understanding the invention, for creating an optically-readable marking on a moulded product, for use in the arrangement of Figure 4;

Figures 6 and 7 illustrate a moulding method in accordance with an embodiment of the invention;

Figures 8a to 8c illustrate steps in a moulding method, using the apparatus of Figure 4;

Figures 9 to 20 illustrate some alternative embodiments of devices useful for understanding the invention, or according to the invention, for creating an optically-readable marking on a moulded product Figure 1 shows schematically a mould having surface textures, and integrated with heating elements in the form of heating wires. One of the heating wires is activated by passing a current through it, thereby raising the temperature of the shaping area below. During a subsequent moulding cycle, the structures below the heated area are fully replicated in the moulded part, whereas structures below the non-heated areas are poorly replicated. This provides a code on the moulded part with adequate contrast for a scanner to determine the intended configuration and deciphering it as a given code. The mould has a well-defined surface texture consisting of square wells. The second heating element from the left is activated using an electrical power supply. The moulded piece will replicate the

topographical texture in the field heated by the active heating element, while the non-heated elements do not provide good replication in the moulded part. This process gives rise detectable contrast on the moulded part. Any combination of heating elements may be activated.

Figure 2 shows experimental evidence for the implementation of the invention, in which a mould comprising diffractive structures having a linewidth of 500 nm and line height of 500 nm, was heated to various temperatures between 20°C and 80°C. The moulded parts shown in Figure 2 represent these mould temperatures, showing how the optical appearance of the replicated structures changes.

As can be seen, there is a large contrast between textures on the parts moulded at 20°C compared to 80°C, which is adequate for recognition by optical scanning systems.

Figure 3 shows four heat profile (FLIR) images of an encoder surface having 4 individually heated areas which can be individually operated. The images show the effect of raising the temperature from a background temperature of 20°C to values between 80°C and 90°C. Each of the individual fields is heated separately in turn. The switching time was approximately 2-3 seconds in this configuration. The demonstration shows that fast changes between configurations is feasible, as the switching between individual configurations was achieved within 2-3 seconds. Figure 4 is a schematic representation of a preferred arrangement showing a mould and injection moulding tool having an encoder for serialisation according to the present invention. The mould comprises a non-moving section (101), and a moving section (102) which may slide away from the non-moving section to open the mould and release a moulded part. When the mould is closed as shown in Figure 4, a cavity (103) is formed, having the shape of the part to be moulded. It should be noted that the surface properties, in particular the surface roughness, is of particular interest to plastic product designers, such that various erosion processes may be formed on the surfaces of the mould sections that are part of the cavity. The mould cavity typically, but not always, also comprises an inlet region (104) which helps to adjust the flow into the mould cavity, but an inlet does not form a part of the final plastic product and is typically, but not always, removed from the part before further processing. The mould cavity may comprise an outlet or venting region (105), ensuring proper flow of the plastic throughout the mould. The position of the outlet is such that it is the last feature to be filled with molten plastic.

The plastic is prepared in an extruder (110) into which raw material (111), such as thermoplastic polymer is introduced. The extruder heats the raw material, such that it melts, then brings it forward using a screw, which presses of molten thermoplastic polymer into the mould through a nozzle (112).

The flow path of the molten polymer through the mould cavity is generally well understood, the molten polymer first entering the inlet zone (104), filling it in its entirety, before the polymer moves forward into the part of the cavity defining the product to be made (103).

When this cavity (103) is filled, the remaining polymer overflows into the outlet (105). During these phases of polymer injection, the pressure in the mould is generally at or near ambient pressure, or 1 atmosphere. After the polymer has filled this part of the cavity in its entirety, the pressure rises and may reach 1000 bar or more, as desired. The mould halves are brought strongly together by an external clamping force, to overcome the polymer pressure thereby keeping the mould halves (101 and 102) in place. The polymer is then cooled as heats diffuses from the polymer through the interface between the polymer and the mould surface, into the bulk of the mould.

For reasons of efficiency, the mould is commonly actively cooled, by integrating cooling channels in one or both halves of the mould (115) which are connected by hoses (116) that are connected to a thermostat (117) that pumps refrigerated fluid through the hoses and the cooling channels, thus drawing away the heat. It should be noted that some polymers, such as PEEK, require a very high mould temperature, achieved by heating the mould instead of cooling it.

The injection mould is integrated here with a barcode encoder (120), in a fashion that does not interfere with the desired function of the mould. The barcode encoder is connected by one or more cables (121) to one or more control systems (122), where the cables may supply electrical power and or various control signals. The control systems typically comprise a multitude of sub-systems with various functions. The control system and encoder work together, to alter the properties between each moulding in such a fashion that a different barcode is achieved on a plastic part as compared to a previous or any previously moulded plastic part, as is desired.

The control system may work independently, or it may be linked (123) by physical or wireless connections to a further control system (124) comprising a multitude of databases, information handling sub-systems and the general ability to act as a platform for linking an individual product to information relating to the same individual product. A clear separation between control system and further control system may not be obvious, as is commonly the case for embedded systems. Figures 5a to 5b illustrate an encoder sutable for use in the arrangement of Figure 4. The barcode encoder (130) is preferably an insert. The insert preferably has one moulding surface (131) facing the main cavity or the inlet cavity or the outlet cavity. The insert comprises a plurality of components, which may include a casing (135) to provide mechanical load bearing and to provide outer shape of adequate geometrical specification and tolerances. The encoder includes include a first segment (136) comprising one moulding surface, a second segment (137) comprising components providing electrical connectivity and a third segment (138) acting as a mechanical load bearing element attached to the insert or mould by machine screws (not shown) and with a plurality of openings for electrical cables. One or more segments may contain active cooling (not shown), such as by cooling channels.

The segmentation example here is not representative of all cases. As an example, the casing (135) may be omitted, and other segmentation may be utilised.

Figure 5c provides more detail of resistive heating elements (141) connected by insulated electrical wires (140) to a connector (142). The connector acts as a socket to simplify attachment of a cable (143) comprising a multitude of signal and electrical power cables. It may be advantageous to replace some of the cables by wireless signal connectivity, examples include Bluetooth, WiFi and other practical standards. The insert may comprise only rudimentary electrical connectivity, or it may comprise higher levels of electrical systems integration up to and including on-board computation and signals preparation.

Figure 6 illustrates schematically a section (150) of a surface volume of a barcode encoder (120) with topographical surface texture (153) thereon, comprising heating elements (151) that are connected by individual wires (152) to external electrical sources. The electrical elements are provided to allow an electrical current to pass through them. This may be achieved by providing suitable electrically insulating materials around the wires and the heating elements. A practical solution may utilize the bulk material as common electrical ground. When electric current is passed through an individual heating element an amount of heat will be generated, which will be dissipated to the surrounding material, thereby heating it. An amount of heat will raise the temperature of a limited area of the surface located near above the heating element, thereby allowing the polymer to penetrate deeper into the features of the structures on the surface of the insert as compared to un-heated areas where polymer will penetrate into the features of the structures to a lesser degree. When the electrical current is no longer applied, the heating will stop, and the surface will cool due to the dissipation of heat through the insert away from the surface, optionally assisted by a cooling system.

The temperature affects the replication of surface structures in the plastic part (as illustrated in Figure 7). When polymer (155) passes over the surface of the insert comprising a surface structure, a comparatively cold section of the mould (156) will allow the polymer to penetrate to a smaller extent into the depth of the structures, replicating the recessed volume of the individual structures partially (158), and at least up to a given first percentage of the volume of the element. When subsequently the polymer passes over a different area of the same mould that is heated to a comparatively higher temperature (157), the polymer will pass over the structures and penetrate into the structure to a higher extent (159), achieving a second percentage of the volume. The difference between the lower degree of filling and higher degree of filling is enough to achieve optical contrast between the two areas.

The requirement for the values of the first and second replication percentage, and the difference between them, is determined primarily by the detection limit of the detection system. In case of vision systems, the lighting conditions and camera angles are well controlled, while camera and optical lens quality is typically high, therefore reducing the contrast requirement. Also, the type of structure affects the said requirements. Note that if the cold areas of the insert surface are very far below the solidification temperature of the polymer, it may be possible to achieve contrast for very large structures, even above 0.1 mm of feature size. The overall mould temperature must be carefully managed to achieve proper replication any level of surface structure and geometry, but determination of the requisite temperatures is well within the remit of one of skill in the art. Even for very low roughness surfaces a temperature influence on replication may be observed.

Optical diffraction gratings may be linear structures of box-like rectangular geometry. In an example the width of each line is near 500 nm and the separation between the lines is near 500 nm, causing the resulting diffraction effect to be weak when replicated from the colder areas, and strong when replicated from the warmer areas. Randomized structures act as diffusers, such that the diffusive effect will be weak when replicated from cold areas, and strong when replicated from warmer areas. Some structures may present both optical properties, or other optical properties derived from surface structures.

The application of the heating current should preferably be optimized in relation to the injection moulding cycle. Strongly depending upon the size of the mould, the polymer material properties, the number of injection points and many other factors, a mould is filled over several seconds down to less than a second, after which the polymer is allowed to cool and solidify by dissipation of heat through the mould to the mould exterior. As an example (illustrated in Figures 8a to 8d), as the polymer is injected to a first stage (160) the heating elements of the insert remain un-activated. As the polymer injection reaches a further stage (161) all relevant heating elements are activated. After the polymer flow front has passed over the insert to an even further stage (162) all heating elements are now switched off. They remain switched off after the mould is filled for as long as the part cools (163). This method of operation has several advantages, including that a minimum of total heat is applied on the insert, ensuring the fastest cooling cycle of the part.

In a different method, resembling the variothermic method, all heating elements of the insert are kept at a low temperature while the mould is filled with polymer, such that structures are replicated to a low extent. Then the desired heating elements are turned on, achieving temperatures adequate to soften or melt the polymer immediately above the heating element, thus allowing the polymer to penetrate into the structures in the same areas, optionally assisted by the clamping pressure on the mould. The insert pressure may be optionally enhanced by pressing it into the mould cavity using a suitably fitted actuator. An alternative encoder is illustrated in Figure 9, in which steel plate (201) with a thickness of 0.5 mm, is coated with hydrogen silsesquioxane ("HSQ") and diffraction gratings (202) all having same line width, arranged in "tiles" of 20 x 20 pm that are alternating in direction of lines. The elevated area comprises about 50% of the total surface area, while the depressions are lines comprising roughly the remaining 50%.

In order to provide means for heating the areas (212), an array of cylindrical epoxy pads (205) having a defined resistivity of 50 Ohm*cm are placed on the other side of plate (201), by means of a suitable stencil. Each pad is 1 mm in height and 1 mm in diameter. A thin PTFE-insulated wire (207) is fixed to the free flat surface of each cylinder (the lower surface, as shown in Figure 9) using silver conducting epoxy (206). All wires are soldered to the terminals of a socket (208), for connection of a flat cable (209).

The volume between the steel plate (201) and a second plate (215) and the insert casing is filled with a heat conducting composite epoxy (210) of high strength, or other suitable potting material, taking care to avoid air inclusions, by judicious use of vacuum cycling.

The mechanical load and the cooling is managed by means of a further backing plate (216) having a cooling channel (217). The backing plate is produced by means of 3D metal printing, which enables the production of cooling channels (217). The backing plate holds the heating elements and wires in place in the casing (200) by means of suitable screws (218).

Figure 10 illustrates yet a further encoder, in which a steel plate (230) with a thickness of 0.3 mm is provided on its surface with an optically diffusive structure (231) by means of laser etching. The opposite side is coated by means of silk screen printing with a 9 pm thick layer of pre-cursor for dielectric electrically insulating material (232) having circular holes of 0.3 mm, in a square array where each circle is separated by 2.0 mm in both directions.

The dielectric material is fired by heating it in a suitable heating cycle, up to 850 C. A precursor for producing thick film resistor material is applied by means of a second stencil, in an array of pads matching the holes, such that each contiguous pad (233) touches the steel at a single hole, and extends from the hole to achieve a flat film resistor of a well-defined end-to-hole resistance of about 1000 Ohm. A wire (235) is soldered (234) to the tip of each pad for connectivity. Suitable connectivity and potting for mechanical stability is applied as described above. A voltage of 24 V may be applied to an individual pad, to apply 1 J of heating energy in the steel material above said pad, by which it heats about 50 C from the chosen base mould temperature.

An embodiment of an encoder is shown schematically in Figure 11, in which a steel plate (240) with a thickness of 0.3 mm is provided on its surface with an optically diffusive structure (241) by means of detergent-assisted randomized fluoric acid etching. Subsequently, a semi-random pattern of small holes is etched in the surface, whereby each hole has depth and diameter of about 20 pm, with a typical separation between two nearest holes of 150 pm. The purpose of this hierarchical structure is to make the codes on the plastic part more robust in practical usage, as the holes in the structuring surface will lead to raised bumps on the plastic part, serving to keep away objects or materials that may damage a code. The particularities, such as the specific dimensions, are less important compared to the hierarchical nature of the combined structuring method.

The opposite side of the steel plate is coated with a 9 pm thick layer of pre-cursor for dielectric electrically insulating material (242) which is fired by heating it in a suitable heating cycle, up to 850 C.

Circular holes are punctured in the dielectric layer by means of laser ablation 0.3 mm diameter, in a square array where each circle is separated by 2.0 mm in both directions. The resistor pre-cursor material is coated all over, filling in the holes in the dielectric and touching the steel, and subsequently fired at a suitable temperature. Some areas of the thick film resistor are removed by laser ablation, forming an array of pads matching the holes in the dielectric, such that each contiguous pad (243) touches the steel in a single hole, and extends from the hole.

A pre-cursor for thick film ceramic conductor material is placed by means of a stencil as small terminal pads (244) on each resistor having a size of 0.3*0.3 mm, to achieve a flat film resistor of a well-defined end-to-hole resistance of about 1500 Ohm. In a separate operation, a printed circuit board stack (253) comprising several layers of ceramic alumina (250), with a suitable copper wire layout (252) and penetrated by a suitable arrangement of vias (251) is made. The via pads on the surface of the stack are provided with soldering material. The stack is coated with a thin layer of potting material for electrical insulation and mechanical stability. The stack is brought against the steel plate and resistor arrangement, such that each resistor terminal rests against a pad connected by via. A heat cycle to 250 C ensures permanent electrical contact between via and resistor terminal.

A connector socket (255) is soldered to the vias, ensuring electrical connectivity from each resistor to the connecting multistranded cable (256).

Yet a further encoder is shown schematically in Figure 12. The encoder is produced as an insert (300) having a suitable geometry to enable it to be assembled in the arrangement of Figure 4. A steel plate (301) having a surface structure (302) is affixed by a suitable means (not shown) from the cavity side. The steel plate (301) is formed from a tool steel with a thickness of 10 mm, and is milled with a square array of blind channels (305), each having a depth of 9.6 mm, leaving a thickness of 0.4 mm between the bottom of the hole and the immediately opposing face (302) bearing the surface structures. Each channel has a diameter of 0.9 mm, and all channels are spaced with a pitch of 1.57 mm in both directions of the square array (see also 332).

A matching array of spring-loaded pins (306) each having a total length of 16.35 mm, a pin diameter 0.5 mm, and a casing diameter of 0.68 mm, is mounted in a suitably prepared printed circuit board (310) comprising suitably designed vias (311) and wire tracks (not shown).

A first connector block (312) allows electrical connection via a cable (313) of half of the pins, the remainder being connected via a second connector and cable. The pin and PCB and cable arrangement is mounted from the exterior of the mould, in a mounting method which permits for ease of mounting and servicing and simplification of replacement of wear parts. A cooling arrangement is not shown.

In use, a current is be passed through a suitably selected number of pins. The contact resistance between the tip of a pin (306) and the steel plate (301) ensures that the electrical energy is released in the vicinity of the tip, thus heating the structured mould surface only in the area immediately above the pin.

In a modified approach illustrated in Figure 13, a brass plate (320) of similar geometry, having a topographically textured surface (321), is prepared by

Electrical Discharge Milling (EDM). An amount of resistor material (325) (epoxy or ceramic thick film precursor or other material having a defined volume resistivity) is metered into the bottom of each hole by means of a syringe, and a suitable curing or firing cycle is performed. Other aspects including the pin (326) and PCB configuration (328) are as in Figure 12, except that the pins are separated from the plate by resistor material 325. The heating element resistance is now determined by the total resistance of the resistor material in that particular configuration, which may be near 320 Ohm.

A voltage of near 40 V is applied onto the pin, such that a current of 125 mA is passed through the resistor, for 100 ms, such that 0.5 J of heat are supplied to the resistor. About half of all pins are supplied with a current, such that in a case of a 21 x 21 pixel QR barcode, a total current of 27 A is passed through the encoder. This is achieved by means of a transistor array controlled by a serial bus, applying the desired level of current to each heating element.

Figure 14 illustrates a further modified approach, in which a steel plate (330) is coated with HSQ, then imprinted with a flat plateau pyramidal structure

(illustrated here only by pyramids 331) having depth of 1 pm and slope angle of 40 degrees. The elevated area is approximately 25%. The reverse side of the steel plate is provided with an array of resistive elements (332) by means of direct placement of conductive composite epoxy material having a well-defined resistivity, using a syringe. Due to process variations, the individual resistive elements do not always have pair-wise identical resistance and a variation between resistance values can therefore arise.

A second plate (333) is prepared, from copper beryllium, and having an array of matching holes, in which the hole diameter is larger than the outer dimension of each individual resistive element such that the copper beryllium plate is not in direct contact with any resistive element. This helps to ensure that all current is drawn toward the first plate and resistive heat development occurs as near as possible and even partially within the steel material.

A control system is provided, having the ability to control the voltage applied to each individual heating resistor element. The control system includes a camera, able to detect the contrast between individual pixels in the moulded product immediately after each moulding.

The control system uses the measured individual pixel contrast levels to adjust the applied voltage from a nominal value of 32 V to individual values ranging between 25 V and 40 V, or as is needed, to ensure optical homogeneity of the field elements over the surface of the encoded area. A similar control system may also compensate for uneven heating and cooling, such that pixels near the edge of the array of heaters may imprint with the same level of contrast and fidelity as pixels near the centre of the array. In a similar approach, the same described system may imprint an image consisting of pixels of varying scattering. This approach can be used as means to hide or conceal a barcode embedded in a grey-scale image defined by controlled imprint variation of surface roughness.

In a further modified approach, illustrated in Figure 15, a steel plate (335) has a first surface roughness achieved by using a specific diamond polishing paste (e.g., a 9 pm diamond paste). A ceramic resistor paste is applied by means of a stencil and fired, leading to pads (337) of resistive heater material in a rectangular array, in which each pad has a rectangular shape and the pitch of pads in one direction is similar to that in a perpendicular direction (not illustrated). The first surface roughness is coated by a hardness coating achieving a first surface structure (336). By means of metal 3D-printing, a new section (338) is gradually applied in layers having a strong attachment to the first steel plate, to eventually achieve a hole-like structure.

In a further modified approach, a steel plate is provided with holes with a size of 3 mm in diameter and a depth of 10 mm and a pitch of 4 mm. A surface structure is achieved by direct tapping using a thin metal stylus. A ceramic zirconia pin having a length of 20 mm and a diameter of 1 mm is wound with copper wire having a thin lacquer dielectric coating and a thickness of 0.9 mm is wound 6 times around the tip of the pin, forming a coil. The pin and coil is inserted into the hole such that the coil is located at the bottom of the hole. The process is repeated to provide every hole with a similar coil.

The reverse side is filled with high temperature heat conducting potting material, for example a zirconia material of the type available from from Aremco

Ceramacast. A backing plate is provided and the assembly is then cured using a suitable curing temperature program.

Each individual coil is connected to an individual high-frequency oscillation circuit which may be controlled by a control system. When high frequency current is passed through an individual coil, this gives rise to eddy currents in the steel material immediately in front of the coil causing a fast and controllable

temperature increase.

Figure 16 illustrates a further embodiment of an encoder, whereby a steel body (400) is prepared with a plurality of blind holes arranged in a square array. The steel body is prepared on the top with a material (401) having thermal effusivity below 2500 Ws°-⁵/(m²K) and a thickness of approximately 3 pm. The material is processed by e-beam milling to achieve a fraction of elevated area of 75%, interspersed with circular holes of characteristic diameter of about 2 pm and depth of similar value. Each blind hole is fitted with an SMD resistor (402). Each SMD is prepared prior to fitting with two insulated cables (403) that have been soldered to each terminal of the SMD - the cables may be mono-wire, or have two or more wires in a single sheath - the cables for several individual SMDs may be bundled for practical reasons.

Each SMD is glued in the bottom of their respective holes using a thermal epoxy of high thermal conductivity (404). The SMD resistor face comprising the thick film resistor material faces against the bottom of the hole, to encourage heat to migrate that way. A larger amount of thermal paste may be added (405) and (406), to improve thermal conductivity and mechanical strength of the whole. The total thickness of the body (410), the depth of the holes (411), the characteristic diameter of the holes (412) as well as the hole separation (413) are chosen to minimize pitch (414) while maintaining thermal properties and mechanical durability. The holes are circular in shape is this is more practical for the machinist, however, any suitable shape may be chosen.

Figure 17 illustrates a further embodiment of an encoder, whereby SMD resistors may be brought into the holes of the body in a more controlled fashion. A first PCB multi-layer stack is prepared with suitable connectivity, such that layers (420) are thick. Vias (421) of a suitable length of more than 1 mm are capped by landing pads (422) while the other ends connect to connective wire tracks in the bottom section of the stack (423). This stack may optionally include 1 or more flex-PCB layers as is suitable for acting as suitable multi-signal wire. After preparation, SMD resistors are mounted on all landing pads (424). After this step, micro-milling is performed remove material around each set of vias, resulting in free-standing pillars having characteristic diameter (425), pitch (426) and height (427), matching substantially with those of the receiving body, comparable to Figure 16. Each hole of the body is filled with a small amount of thermal paste, carefully placing the paste in the very bottom of each hole by means of a syringe and needle. The machined PCB with optional flex-BCP is now mounted into the receiving body.

Figure 18 illustrates a further embodiment of an encoder, which takes into account the potential weakness of the pillars (430) produced by the previously described means, where the pillars may be destroyed during the milling procedure. Instead of holes in the steel body (400), a set of receiving trenches are milled. The counterpart PCB with optional flex-PCB is milled into free-standing ridges (431, where only one such ridge is shown without the bottom PCB layers). Each ridge comprise multiple pairs of vias for addressing SMDs. This approach has the disadvantage that more steel material is now removed, reducing now the strength of steel body. Modifications of this approach are illustrated by (432), where some of the material between via pairs is removed (not showing the bottom PCB layers providing connectivity), allowing for more steel in the body. Noting that square or rectangular features may be difficult to mill with accuracy, (433) shows a modified approach whereby via pairs are now finished into round pillars resting on ridges (not showing the bottom PCB layers providing

connectivity), which will remove more of the PCB material allowing for more material volume in the steel body, thereby strengthening it against the moulding pressure.

Figure 19 shows a further embodiment of an encoder, whereby two neighbouring via pairs (440) having landing pads (441) are joined by material (442), which improves the feasibility of milling by strengthening a pair. This will allow for taller pillars. The pairs may be arranged in a pattern as (443), whereby clusters formed by pairs of pairs of via pairs, each cluster providing 4 controllable heating elements, each cluster arranged in alternate sense of direction compared to its nearest neighbours, providing thereby a PCB connectivity that is feasible to mill, with a minimal impact on the strength of the body. A further modification reduces slightly the height of the material joint (444), leaving the pillars substantially round, and adding an optional via (445) for the purpose of adding strength and thermal conductivity to the PCB. Further such thermal dissipation vias may also be added to the bottom PCB layer providing connectivity (not shown).

Figure 20 shows a further approach, a section through one embodiment. A mould (500) is foreseen with a suitable cut-out hole. An insert made substantially of steel (501) is placed in this hole. A flex-PCB stack for connectivity (502) is placed to fit snugly in a hole cut in the insert. One part of the flex-PCB is mounted with suitable SMD resistors, on top of which is disposed a suitable metal sheet (503) having a coating of HSQ imprinted with holes having a depth of 500 nm. The steel insert (501) is made in several parts, allowing for the flex-PCB to bend out and away from the shaping surface. When the steel insert is assembled, the flex-PCB wire strip fits snugly, whereby the end of the strip extends away from the insert, allowing for mounting of a connector block (504) for later attachment of a suitable cable having mating connector layout. The SMD resistors (510) are placed on top of the flex-PCB stack as mentioned, where between the metal sheet (503) and the flex-PCB construct is filled a suitable amount of epoxy having a high thermal conductivity and mechanical strength upon curing (511). The connectivity in the flex-PCB is shown (512) to extend to different layers in the stack. The design is made snug, so that moulding pressure loads can be transferred suitably through the epoxy, SMDs, flex-PCB stack and further into the material of the steel insert. The flex-PCB stack is trimmed around the edges so it fits snugly against the cavity in the steel insert, so that loads can be transferred without substantial stretching of the flex-PCB material. The loads can be transferred from the metal sheet (503) also by means of one or more steel pins (520), which penetrate the flex-PCB through holes that have been foreseen during the preparation thereof (not shown).

In yet a further alternative embodiment, a printed circuit board (PCB) stack comprising high strength alumina is provided, with a suitable via and copper wire arrangement and connector blocks. The top-most surface of the PCB stack includes surface mount device (SMD) thin film resistors in package size 0201 having a length of 0.6 mm and width of 0.3 mm. The SMD resistors all have the same resistance of 910 Ohm. In a separate work flow, a zirconia ceramic plate having a thickness of 0.5 mm is provided with a randomized surface structure by means of laser etching. The structured zirconia plate is attached to the PCB stack by means of a potting compound to achieve a monolithic stack, which has the desired functionality comprising individually addressable resistive heaters.

In further embodiments, the top ceramic plate may be replaced with almost any other material and structuring method. Likewise, the SMD resistors may be replaced by thick film resistor paste applied in a separate work-flow.

DETAILED DESCRIPTION OF AN EMBODIMENT

In a first example a mould for a medical device requiring individual traceability is mounted with a 21x21 array of heating elements, in the form of spring-loaded pins resting on the backplane of a shaping surface. The topographical texture is achieved by a lithographically defined etching method, achieving an effective optical diffuser. The desired configuration of the code is achieved by heating the relevant individual heating fields, achieved by activating the relevant heating elements.

The mould is used to mould one medical device, whereafter the configuration of the array is changed by activating a different combination of heating elements. After re-configuration the mould is used to mould a further medical device with a new and unique 2D barcode.

Before use of the medical device, the user may scan the 2D barcode in order to obtain confirmation that the individual product is within specification, and to obtain to additional and up-to-date information about the use of the product, and to send a message to the manufacturer about where the device is used, in order to be able to contact the user if problems with the product batch should arise in the future.

In a second example a mould for a car part is mounted with an array of heating elements having individual triangular fields which are 1 mm in side length, arranged in a triangular fashion with 15 elements to each side. The topographical texture is achieved by sand-blasting with an abrasive medium. The mould is used to mould one part, and after the configuration of the array is altered by activating or de-activating at least one heat element. After re-configuration the mould is used to mould a further part with a new and unique 2D barcode. The barcode may be read by taking a photograph using flash illumination, for instance using a conventional smartphone.

The barcode links to an internet page accessible by the smartphone with documentation, use, replacing and recycling instructions which may be accessed if the part needs replacement, or as confirmation of choice of replacement part. Furthermore, the user confirms that the part has been mounted in a car.

Furthermore, in the event that the selected part is an illegal copy of an original and copyright protected product, accessing the database either with a wrong or a previously used code will generate a warning, informing the user and the parts manufacturer, that the particular part is an un-registered copy of an original spare part.

In a third example a steel insert is mounted in a hole provided in an injection mould. The steel insert comprises a flex-PCB construct comprising an array of SMD resistors disposed on a first surface. The steel insert is capped by a metal sheet comprising a coating of diamond-like carbon, which has been subsequently lithographically etched in a pattern to provide 60% elevated area interspersed with depressions in the shape of holes in a square array, each hole being roughly identical to all other holes. A portion of the flex-PCB forms a strip which extends away from the shaping surface of the steel insert.

In a fourth example several encoders are disposed in the same mould, whereby one encoder expresses the same barcode for a substantial number of moulding cycles, whereas a second encoder is tasked to continuously provide new barcodes for every moulding cycle.

In a fifth example a steel body is provided with a plurality of holes in a geometry substantially matching with a set of substantially cylindrical pillars combined with rectangular shapes, comprising a plurality of vias, fabricated by milling of a previously prepared PCB stack being already mounted with SMD resistors and having connectivity provided by a flex-PCB portion of the stack. A roll of extruded polymer film is heated and entered into a mould for vacuum forming. During the vacuum forming process the steel body is provided at a suitable elevated temperature. The desired barcode is expressed on the shaping surface of the insert by addressing the corresponding SMDs using the connectivity including the vias. The insert is now pressed into an area of the heated polymer film, against the support provided by the vacuum-forming mould.

Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms "comprising" or "comprises" do not exclude other possible elements or steps. Also, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous. All patents and non-patent references cited in the present application are also hereby incorporated by reference in their entirety.

Claims

1. An insert for a moulding tool having a plurality of shaping areas used for a moulding or forming process, the insert being adapted to create a machine-readable marking on a surface of a product during a moulding or forming process;

a first body comprising a topographical texture on a first side;

a plurality of printed circuit board layers comprising metallic interconnects, landing pads and vias;

a plurality of surface mount resistors providing a plurality of temperature controlling elements each capable of heating a localized region of the encoding area;

wherein the plurality of surface mount resistors is disposed on a first side of the said plurality of printed circuit board layers, and is located proximate a second side of the said first body.

2. An insert according to Claim 1, which comprises fields in the encoding area of the shaping surface that are configured so as to produce a machine-readable marking which is in the form of an optically readable code, preferably wherein each said field has an area of from 0.1 mm² to 100 mm².

3. An insert according to any one of claims 1 to 2, wherein the said topographical texture on the said encoding area is disposed on a fraction from 25% to 100% of the area of the said shaping surface.

4. An insert according to any preceding claim, wherein the said topographical texture comprises surface structures characterized by having elevated areas;

the said elevated areas surrounded by non-elevated areas having an average depth of from 0.025 micrometer to 25 micrometer.

5. An insert according to any preceding claim, wherein the said encoding area comprises a first surface material having a first thermal effusivity below 2500 Ws^{0 5}/(m²K).

6. An insert according to claim 5, wherein the said first surface material of the encoding area has an average thickness from 0.010 micrometer to 10.0 micrometer.

7. An insert according to any preceding claim, further comprising a thermally conductive material filling a volume disposed between said resistors, said first side of the said plurality of printed circuit board layers and the said second side of the said first body.

8. An insert according to any preceding claim, whereby the said plurality of printed circuit board layers comprises a first plurality of flexible printed circuit board layers and an optional further plurality of non-flexible printed circuit board layers;

wherein a first portion of the said plurality is arranged in a stack, and wherein one or more of the said flexible printed circuit board layers of the said first plurality of flexible circuit board layers extend beyond the encoding area, thereby forming a flexible wire comprising a plurality of metallic interconnects;

said flexible wire disposed to the side of the device and leading in a direction away from the said shaping surface of the said encoding area;

said plurality of printed circuit board layers being supported mechanically by a support body;

said flexible wire comprising a connector.

9. An insert according to any preceding claim, whereby a portion of the said printed circuit layers is sandwiched between the said first body and the said support body; said portion of printed circuit board layers comprises a plurality of perforating holes; said support body comprises a plurality of support pillars;

said support pillars extending from the surface of the said support body so as to engage with and extend through one or more of the perforating holes.

10. An insert device according to any preceding claim, whereby the said first body and/or the support body are formed of a metallic material, and preferably wherein the first body is in the shape of a sheet having a thickness between 0.050 mm and 2.000 mm.

11. An insert according to any preceding claim, whereby the first body and/or the support body has a first thermal effusivity above 7000 Ws°-⁵/(m²K); preferably the said first body comprises a plurality of further material layers comprising a first surface material on the first side of the first body.

12. An insert according to claim 11, whereby the said plurality of material layers comprising a first surface material on the first side of the first body has a total thickness between 25 nanometer to 25 micrometer.

13. An insert according to any one of claims 1 to 7, whereby the said plurality of printed circuit board layers comprises a first plurality of stiff printed circuit board layers and an optional further plurality of flexible printed circuit board layers;

whereby a portion of the stiff PCB material has been removed to create a plurality of pillars;

the said plurality of pillars each comprising at least one set of vias for addressing at least one SMD resistor.

14. An insert according to Claim 13, wherein the said body is provided with blind channels to substantially form a negative receiving geometry mating with the said plurality of pillars formed on the said plurality of printed circuit boards.

15. A device according to Claim 13 or 14, whereby the shape of the said plurality of pillars may be cuboid, cylindrical, two or more cylinders on top of cuboids, two or more cylinders joined by boxes, or substantial variations or combinations thereof.

16. An insert according to any preceding claim, whereby the said topographical texture on the said shaping surface comprises a plurality of elevated areas interspersed by a plurality of depressions;

the said elevated areas having a surface fraction from 20% to 95%.

17. An insert according to Claim 16, whereby the said depressions have a mean depth below the elevated areas in a range from from 25 nm to 25 micrometer.

18. An insert according to Claim 16 or claim 17, whereby the said plurality of depressions have depths relative to a running mean with sampling length of 100 pm characterized by having an arithmetic mean deviation of from 15 nanometer to 15 micrometer.

19. An insert according to any one of Claims 16 to 18, whereby the said plurality of depressions may be a plurality of holes;

whereby the plurality of holes have openings which may be characterized by being substantially square, rectangular, diamond-shaped, round, elliptical, pentagonal, hexagonal, heptagonal, octagonal, or a mixture thereof;

whereby the surface area of the said openings is preferably from 2500 nm² to 100 pm²;

and whereby the mean separation between the rim of a first hole and that of a nearest neighbouring hole is preferably from 25 nanometer to 25 micrometer.

20. An insert according to any one of Claims 16 to 19, whereby the said plurality of depressions is a plurality of trenches;

whereby the plurality of trenches have openings which may be characterized by being substantially elongated or wavy elongated rectangles;

the said rectangles preferably having a short axis length across the said trench of from 100 nm to 3 micrometer, and a long axis length along the said trench of from 5 micrometer up to and including the entire width of the said encoding area.

21. An insert according to any one of the preceding Claims, wherein the said topographical texture is produced by a surface processing step selected from the group consisting of: lithography, masking, etching, blasting with a blasting medium, grinding, sanding, polishing, lapping, laser machining, laser engraving, anodic oxidation, electro-plating, electro-polishing, sol-gel processes, embossing, imprinting, nanoimprint lithography, curing, sintering, sputtering, etching, dry reactive ion etching, scribing, ruling, tapping and any combination thereof.

22. An insert according to any one of the preceding Claims, comprising one or more materials produced by means of simple or multi-material 3D printing.

23. An insert according to any one of the preceding Claims, whereby the said shaping surface further comprises a covalently bonded molecular layer, and optionally further comprises an ionically bonded metal-oxide layer, for the purpose of reducing the surface energy or tension; preferably wherein the covalently bonded molecular layer comprises surface reactive molecules or coupling agents, more preferably selected from the group consisting of molecules providing silane, orthotitanate, thiol or zirconium based surface coupling reactions;

preferably wherein the said optional ionically bonded metal-oxide layer is selected from the group consisting of: quartz, amorphous quartz, aluminium oxide, nickel oxide, nickel alloy oxide, steel oxide, vanadium oxide, chromium oxide, titanium dioxide, silicon dioxide, and any allotrope, alloy, mixture or combination thereof.

24. An insert according to Claim 23, whereby the said surface reactive molecule or coupling agent is selected from the group consisting of perfluorododecyl

trichlorosilane, perfluorododecyl trimethoxysilane, perfluorododecyl triethoxysilane, chloro-, methoxy or ethoxy-silanes with suitable pendant groups, titanium alkoxides with suitable pendant groups, zirconium alkoxides with suitable pendant groups, alkane thiols with suitable perfluorinated or other pendant groups.

25. A moulding tool for creating a moulded product or a series of moulded products characterized by having a machine-readable marking on a surface thereof, wherein the mould comprises a device according to any one of claims 1 to 24.

26. A moulding tool according to Claim 25, comprising a plurality of shaping areas surrounding the said encoding area of the said device, said plurality of shaping areas forming a total shaping area, said total shaping area characterized by having a thermal effusivity above 7000 Ws°-⁵/(m²K) on from 50% to 100% of the total shaping area.

27. A moulding or forming system comprising a moulding or forming tool according to any one of claims 25 to 26, or an insert according to any one of claims 1 to 24, and further comprising a controlling board connected to the metallic interconnects of the plurality of printed circuit board layers of the insert, the controlling board comprising :

- a plurality of individually addressable power outputs for the purpose of providing said temperature controlling elements with electrical energy, and

- preferably, a plurality of digital inputs and outputs, - preferably, a plurality of sensor circuits,

- preferably, a plurality of communication circuits.

28. A method for creating a moulded product or a series of moulded products, characterized by having a machine-readable marking on a surface thereof, comprising forming at least the said surface of the product by a moulding process in which a moulding material is caused to contact a shaping surface, wherein the shaping surface includes an encoding area, and wherein the said encoding area comprises a plurality of fields, each field including a temperature controlling element, and each field being individually addressable to enable control of the temperature of the said field in the encoding area in such a manner as to control the extent to which the topographical texture of the surface of the said field is replicated in the moulded product during the moulding process; and controlling the

temperature of individual fields within the encoding area during the moulding process so as to produce on the surface of the moulded product a pattern corresponding to the said machine-readable marking,

wherein the encoding area comprises:

- a first body comprising a topographical texture on a first side,

- a plurality of surface mount resistors, the plurality of surface mount resistors providing a plurality of temperature controlling elements each capable of heating a localized region of the encoding area,

29. A method according to claim 28, wherein the fields are configured so as to produce a machine-readable marking which is in the form of a machine-readable code.

30. A method according to Claim 28 or 29, wherein the shaping surface comprises an insert according to any one of claims 1 to 24, or is provided by a moulding or forming tool according to any one of claims 25 to 26, or a system according to claim 27.

31. A method according to any one of claims 28 to 30, wherein the said moulding material is selected from a thermoplastic polymer, a thermoset polymer, a polymer composite, a polymer precursor, a crosslinking elastomer, a polymer film, a metal, a metal alloy, a ceramic, a ceramic precursor, a composite, a molten metal, and a molten alloy.

32. A method according to any one of claims 28 to 31, wherein the said forming is carried out by a method selected from injection moulding, variotherm injection moulding, blow moulding, casting, compression injection moulding, roll-to-roll extrusion coating, thermoforming, vacuum forming, gas assist moulding, vacuum assist moulding, film insert moulding, structural foam moulding, investment casting, roll-to-roll extrusion casting, calendaring, stamping, embossing and hot embossing.

33. A method according to any one of claims 28 to 32, further comprising the step of changing the configuration of individually addressable temperature controlling elements to a new chosen configuration between each cycle of production.

34. A method according to any one of claims 28 to 33, in which the topographical texture comprises a plurality of depressions, and the said plurality of depressions of the said topographical texture are at least partially replicated in the surface of a moulded product during a first moulding process characterized by a first

temperature of a first field of the said shaping surface.

35. A method according to claim 34, wherein, where the first field is not heated, the replications of the depressions in the first field have heights above the replication of the elevated area of from 0 nanometer to 50 nanometer.

36. A method according to claim 34 or 35, further comprising a second moulding process according to claim 33, wherein the said plurality of depressions of the said topographical texture are at least partially replicated in the surface of a second moulded product during the second moulding process characterized by a second temperature of a first field of the said shaping surface, the said depressions of the said topographical texture are replicated with a first aspect ratio in the surface of the first moulded product, and with a second aspect ratio in the surface of the second moulded product, wherein the second temperature of the said first field of the said shaping surface in the second moulding process is different from the first temperature of the said first field of the said shaping surface in the first moulding process by from 10°C to 100°C, and preferably wherein the said increase in aspect ratio is from 1 to 5000 times.

37. An insert, moulding or forming tool, system or method according to any preceding claim, wherein the said differences in topographical texture encode digital information, which is readable by a device comprising at least one light source and one imaging system for detection of replicated and non-replicated areas in said encoding area of the said moulded part.

38. An insert, moulding or forming tool, system or method according to any preceding claim, wherein the said machine-readable code represents information selected from a digital address, a database entry, a serial number, a model number, an internet hyperlink, and internet hyperlink address, a list of consecutive numbers, a list of randomized numbers, a list of clustered numbers, and a traceable code.