DE102014007562B4 - Process for the production of three-dimensional molded parts with integrated pattern structure by additive manufacturing - Google Patents

Abstract

The invention relates to a method for producing three-dimensional molded parts with integrated circuit pattern (30) by additive manufacturing processes (additive manufacturing) of an electrically conductive and a non-conductive material, wherein the molded part of the non-electrically conductive material and the integrated circuit pattern structure from the elektirsch composed of conductive material and the electrically conductive material consists of a TCO ink. The invention also relates to a three-dimensional object produced by means of the method according to the invention.

Description

TECHNICAL FIELD OF THE INVENTION

The invention relates to an apparatus and a method for the production of three-dimensional molded parts with integrated pattern structure by means of additive manufacturing processes (additive manufacturing) of an electrically conductive and a non-conductive material, wherein the electrically conductive material is provided on the surface that selectively there can be deposited by a chemical or galvanic process through and through metallic layer according to claim 1. The invention also relates to a produced by the method according to the invention, three-dimensional object.

BACKGROUND OF THE INVENTION

The use of high-temperature thermoplastics and their structured metallization opens up a new dimension of circuit carriers for the electronics industry: molded-in molded interconnect devices (MID). MID are molded parts with integrated pattern structure. They create enormous technical potential for rationalization and are much more environmentally friendly than conventional printed circuit boards, which they do not replace, but complement each other sensibly.

Essential applications for the MID technology are the automotive electronics and telecommunications, but also z. As well as computers, home appliances or medical technology. Currently, the market has an annual growth of about 20%.

This invention is concerned with producing prototypes and small series of these MIDs by additive manufacturing methods without the use of tools. The spatial injection-molded circuit carrier is composed of the 3D model of the circuit carrier and the 3D circuit layout.

• 1. Herstellung des Schaltungsträgers
• a. Einkomponentenspritzguss
• b. Zweikomponentenspritzguss
• c. Insert Molding (Hinterspritzen der Schaltung/Leiterbahnen)
• 2. Strukturierung des Schaltungsträgers
• 3. Metallisierung des Schaltungsträgers

Essentially, 3 process steps are needed to produce MIDs:

• 1. Production of the circuit carrier
• a. single-component
• b. Two-component injection molding
• c. Insert Molding (insert molding of the circuit / tracks)
• 2. Structuring of the circuit carrier
• 3. Metallization of the circuit substrate

The different production methods can be found in detail in the relevant specialist literature on MIDs.

All methods have in common that in three-dimensional moldings, an injection molding tool for the circuit substrate must be prepared and the circuit layout is either structured by a second, electrically conductive material or the molding material is made conductive according to the layout in order to be subsequently metallized can.

With this large number of complex production steps, small quantities are not economical and the production of prototypes is costly and time-consuming due to the high tool costs and the long production times.

In order to accelerate the production of prototypes and small batches and to make them affordable, additive manufacturing processes are suitable in which multiple materials can be used in a construction process.

In the two US patents US 2014/0 036 455 A1 - "System and Method for Additive Manufacturing of an Object" and US 2010/0 127 433 A1 - "Methods and Systems for Integrating Fluid Dispensing Technology with Stereolithography" are already described processes how electrically conductive materials are integrated into the 3D printing process to produce electrically conductive structures within an additively manufactured component.

Since these structures are not purely metallic structures, they have a high internal resistance and can only be used to a limited extent for traditional circuit path functions, as can be found on printed circuit boards.

In the context of this invention is to be used as an electrically conductive material, a TCO ink (TCO = Transparent Conducting Oxcides / transparent conductive oxides) developed by the Leibnitz Institute for New Materials (INM) and adapted so that they are both a described patent application in a based on photopolymerization, additive manufacturing process and on the other hand correspondingly favorable properties for the trailing, galvanic process for metal deposition and adhesion offers.

The TCO inks contain nanoparticles of transparent, conductive oxides and are produced by wet-chemical processes. Usually, TCOs by means of vacuum coating, such as. Sputtering. This method, newly developed by INM, enables for the first time the direct printing of transparent conductor structures on solid and / or flexible substrates. B. plastic films. The TCO ink can be z. B. in gravure printing applied and cured at <150 ° C by means of UV radiation or cured.

In the US patent application US 2013/0 342 592 A1 "Inkjet printer for printing on a three-dimensional object and related apparatus and method" is spoken by printing a three-dimensional body with conductive ink by means of an inkjet printer.

This invention is based on using the electrically conductive and UV-curable TCO ink within an additive manufacturing process for three-dimensional structuring of the pattern structure in order subsequently to a galvanic process for the deposition of highly conductive metals, such as. As copper or gold to produce permanent Leiterbahen to allow.

• – Drop-On-Powder Technologie
• – PolyJet Technologie
• – 3D-DLP-Printing-Technologie
• – Stereolithographie

The selection of the additive manufacturing methods in this specification is limited to the technologies in which obviously either "inks" or liquid materials, such as e.g. As photopolymers, are processed, limited:

• - Drop-on powder technology
• - PolyJet technology
• - 3D DLP printing technology
• - Stereo

With drop-on-powder technology, layer by layer, a binder material is selectively applied to a powder bed (made of plastic, metal or sand) using printheads to generatively produce three-dimensional molded parts. The advantage of this method is that no support structures are needed because the molding is built in a powder bed. In addition, the method is favorable, since standard print heads from the printing industry (inkjet printer) are used. This technology was developed by Z-Corp. developed to series maturity and now belongs to the 3D-Systems Group.

With PolyJet printing technology, multiple materials with different properties can be processed in parallel in one component.

PolyJet printing technology is a high-performance additive process technology patented by Stratasys.
PolyJet 3D printers offer smooth surfaces, small wall thicknesses and complex geometries thanks to a layer thickness of 16 micrometers and an accuracy of up to 0.1 mm. It's the only technology that can handle a wide range of materials, from rubbery to solid, transparent to opaque.

With the Objet Connex technology even multiple materials can be processed simultaneously in one part and also produce multi-colored parts.

Also, the methods based on classical photopolymerization such as stereolithography and 3D-DLP printing, in which a light-curing plastic selectively curing, would be conceivable, if it can be used with multiple materials within a construction job. This is not the case at the moment because the changing, selective material order / material supply has not yet been technically implemented.

However, a detailed explanation of these known methods will be omitted to avoid unnecessary repetition. In addition, the methods described here are not exhaustive. In principle, any additive manufacturing process can be used to implement the invention, in which the selective application of TCO inks - also as an additional process to the actual process - is possible and meaningful to produce the integrated into the molding, three-dimensional pattern structures.

The invention is based on producing the molded part or the circuit carrier together with the circuit in a 3D printing method and thereby using the TCO ink in the same or an additional method for the generation of the three-dimensional circuit pattern structure.

In this case, the conductive structure thus produced can either itself be used as a conductor, or subsequently additionally metallized. The latter can be done chemically / galvanically.

If the TCO ink is processed via printheads (piezo process, drop-on-demand), such as. As in the case of the drop-on-powder or the PolyJet method, due to the limited process parameters special requirements in terms of viscosity, temperature stability and photopolymerization (light curing). After the selective jetting of the TCO ink for the regions of the pattern structure within a layer, the TCO ink is cured or fixed by means of UV light.

In the PolyJet process this is done in the same process step as the curing of the molding and support material; both are made of a photopolymer.

In the case of the drop-on-powder method, if the actual binder material is not a photopolymer, an additional device for curing the TCO ink, such as TCO ink must be used. As a UV lamp, are integrated into the system.

Because the TCO ink is a transparent material, for practical reasons, it may be useful to color the TCO ink to make the pattern structure in the finished printed part optically recognizable.

The different areas for the selective application / jetting of the different materials for molding and circuit structure are given by merging corresponding 3D CAD files for molding and circuit structure, see 1 ,

In the European patent EP 2 072 223 B1 "Apparatus and method for producing three-dimensional objects from various materials by means of rapid prototyping" describes a possible method for data processing and provision.

• a) ohne Werkzeuge fertigen zu müssen und
• b) dabei die Anzahl der Fertigungsschritte zu reduzieren.

The invention is based on the object, an apparatus and a method for producing three-dimensional molded parts with integrated pattern structure by means of additive manufacturing processes such. B. PolyJet or drop-on powder, using non-electrically conductive materials for the molding and a TCO ink to produce the pattern structure, wherein the actual interconnects are produced by a subsequent chemical or electroplating process by depositing metal on the pattern structure , Thus, it is possible to produce so-called Molded Interconnected Devices (MID) in small quantities up to a piece in an efficient manner,

• a) to produce without tools and
• b) to reduce the number of manufacturing steps.

The object is achieved by a method having the features of claim 1. The independent claim relates to an object produced by means of the method according to the invention.

The known devices and methods of additive manufacturing have so far allowed only a variation of mechanical and optical properties, but not of electrically conductive properties.

By means of the method described in the invention, it is now possible using the UV-curing TCO ink to generate electrically conductive structures both superficially and within a three-dimensional molded part, wherein the actual interconnects by a subsequent chemical or galvanic process by depositing metal on the pattern structure are produced so as to produce molded parts with integrated pattern structure, also known as Molded Interconnected Devices (MID), in small quantities cost-effectively and quickly by means of additive manufacturing. Preferred technologies are the PolyJet and the Drop-On-Powder process.

Further details and advantages of the invention will become apparent from the following purely exemplary and non-limiting description of embodiments of the method, in the course of which details of a corresponding device for carrying out the method are disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

1 shows a diagram in which schematically the merger of the two data sets to three-dimensional molded part (3D substrate) and three-dimensional circuit pattern structure (3D circuit part) to a common object (3D-MID) is shown.

2 FIG. 12 is a diagram schematically illustrating the use of TCO ink within the drop-on-powder process and apparatus. FIG.

3 FIG. 12 is a diagram schematically illustrating the use of the TCO ink within the PolyJet method and apparatus. FIG.

DESCRIPTION OF PREFERRED EMBODIMENTS

In 2 the classic drop-on-powder process is shown in which the binder in the form of a liquid / ink, for. T. also in different colors, held in a tank and applied by an inkjet print head in layers selectively on the powder bed.

In the context of the invention, an additional tank and print head for the TCO ink is now provided and controlled via the software.

An additionally installed UV emitter then moves over the selectively bonded powder layer and hardens the TCO ink.

In 3 the poly-jet process is presented, which has the advantage that the TCO ink is processed similarly to the materials (photopolymers) for molding and support structure. All three materials are applied layer by layer selectively as a function of their 3D data set by means of a drop-on-demand printhead and cured directly after application by means of a UV radiation source.

Stereolithography, or 3D-DLP printing, uses the overhead method, where the component hangs from a support plate that moves up layer by layer exposing the material through the transparent bottom of the material tray becomes. In these two methods, the materials are not applied selectively, but selectively cured by means of laser beam or projection mask per layer and structure of the molded part and conductive pattern. Since the materials are provided over the entire building level in a material tray (with transparent bottom), the material pans of the molded part material and the pattern material (TCO ink) must be exchanged within the generation process of a layer and the layer depending on the 3D data sets Form part and conductor image are exposed.

LIST OF REFERENCE NUMBERS

1

3D substrate

2

3D-MID

3

3D circuit layout

4

Reservoir for liquid binder

5

Reservoir for TCO ink

6

Electromagnetic radiation source

7

Nevelierwalze for powder bed

8th

Chamber for powder feed

9

Lifting cylinder for powder feed

10

powder bed

11

space

12

Electrically conductive structure made of TCO ink

13

Lifting cylinder for powder bed

14

building plane

15

Three-dimensional component

16

Inkjet printhead

17

TCO ink print head,

18

Particle collection vessel

19

GRADER

20

Electromagnetic radiation source

21

component

22

Electrically conductive structure

23

Lifting cylinder for carrier platform

24

carrier platform

25

Reservoir for building material

26

Reservoir for supporting material

27

Reservoir for TCO ink

28

Support structure made of support material

29

Printheads for building material, support material and TCO ink

Claims (9)

A method for producing a three-dimensional object, consisting of a three-dimensional molded part and an integrated three-dimensional pattern structure, by means of an additive manufacturing process (additive manufacturing) using at least one non-electrically conductive and at least one electrically conductive material, characterized in that the molded part of at least one of generated electrically conductive materials and the pattern structure is generated using a TCO ink, wherein the conductive structure thus produced is subsequently additionally metallized and the metallization takes place chemically or galvanically. A method according to claim 1, characterized in that both material groups, electrically conductive and non-conductive, are used in parallel within one and the same additive manufacturing process. Process according to claims 1-2, characterized in that a TCO ink is used as a binder in a drop-on-powder process at the locations for generating the pattern structure. Method according to claims 1-2, characterized in that a TCO ink is used as electrically conductive material in a PolyJet method for producing the pattern structure. Method according to claims 1-2, characterized in that in stereolithographic processes or 3D-DLP printing to produce the pattern structure within a layer, the material tray for the molding material is exchanged with a material tray with the TCO ink , Process according to claims 1-5, characterized in that the TCO ink is colored. Method according to claims 1-5, characterized in that the TCO ink can be fixed by electromagnetic radiation, or curable. A method according to claim 1, characterized in that in the additive manufacturing process, the locations where a) the material for the molding is selectively applied and / or cured and b) the material for the pattern structure selectively applied and / or cured should be each set in a separate record. Three-dimensional object, in particular three-dimensional molded part with integrated pattern structure, also known as "Molded Interconnected Device" (MID), characterized in that it is produced using a method according to one of claims 1 to 8.

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