NL1044237B1 - 3d manufacturing system, extruder system and filament guiding system therfor - Google Patents

Abstract

A 3D printer, in particular for a 3D printing based manufacturing system, comprising a 3D printing device, in which a filament of printing material is driven into a printer head, the printer thereto comprising a so-called filament extruder, which feeds the filament to the printer head, and the printer head comprising a heat block with heating means, the heat block transforming a filament into a molten, at least weakened, preferably plastically deformable state, in which device, the filament is guided in between the extruder and print head by a guiding tube provided with external tube-support means. The external tube support means is in the form of a sleeve, in which the guiding tube is fittingly received freely moveable, which sleeve is connected at each end to a socket for connecting tube support means to the extruder and to the print head respectively, and in which the guiding tube is freely moveable relative to a socket.

Description

3D MANUFACTURING SYSTEM, EXTRUDER SYSTEM AND FILAMENT

GUIDING SYSTEM THERFOR

[0001] The present invention relates to an improvement in a so-called 3D device manufacturing system, in popular sense also known as a 3D printer, an improved print head and manner of using or operating a print head.

[0002] So called 3D printing based device manufacturing systems have been out in the art ever since 1982, however have presently not only become popular in amateur or hobbyist areas for various purposes, but have also in industry become established as a professional means of producing devices or spare parts. The economic significance of these systems not only resides in the ability to relatively easily create special shapes or to quickly create prototypes for testing purposes, but also in on demand supply, saving various forms of costs like in storage, transport and administration.

[0003] While cost and efficiency are important to hobbyists, these features are equally important to industrial systems. In industry hence, relatively expensive systems are afforded in order to be able to produce of try-out swiftly, i.e. without loss of time as may be experienced in more simple, typically denoted amateur systems. At the same time, quality of printing of an object is of prime importance, not to be sacrificed upon, which can be a challenge, especially in combination with high speed of printing, i.e. of expelling large volumes of molten material for forming an object to be printed.

[0004] In recent years, e.g. along patent publication WO2019226043 in the name of

Applicant, a tendency may have been noticed towards larger printing volumes in smaller, less expensive printers, e.g. by improving the extruder part of a 3D printer. Quality in such high volume printers may however suffer, amongst others in the form of so-called oozing, or dripping in case of transfers of a print head to another location, in that timely retraction of fed filament may be an issue, casing unwanted spillage of material at the object. This is e.g. identified as is identified by Mateusz Schyboll in the public internet post “PTFE bowden tube upgrade with TESA MONOFILAMENT” of the Hypercube free speech group, at web-location https://www.facebook.com/groups/Hypercube.Evo/permalink/192106034761003/.

Schyboll indicates that the biggest problem in Bowden systems is the stretching of the

PTFE tube. He suggests upgrading a filament guiding tube, a PTFE tube with TESA

Monofilament along the length of the guide tube and uses zip ties to secure the tape along the tube, and reports improvement in retraction characteristic, in that he indicates no longer to need to switch to “high” retraction speed, often combined with long retraction distance, which is normally understood as to be in order to prevent dripping.

[0005] A subsequent article, “Would adding fiberglass packaging tape to a Bowden tube be beneficial” provide three reasoned statements pointing to other causes of uncontrolled dripping, including slack in the gap between filament and tube, the securing of a tube at each end, a calculated statement to support that filament versus guiding tube length differs due to filament in tube deformation rather than extension of the tube. In this second rebuttal it is suggested to use bike gear Bowden cables instead, cutting away some of the external diameter at the ends of the cable so as to fit print head and extruder, while the third rebuttal explains that filament contraction is a more likely cause of untimely material retraction than tube extension as concluded by Schybol. The fact that Bowden coupling apparently is of high relevancy in print quality is underlined by an article such as “Bowden coupler review” of October 2017 by author Walter at http://thrinter.com/bowden-coupler-review.

[0006] It is remarked that for overcoming drip or oozing problem in general, various solutions have been proposed. The print head of such systems very often is derived from preceding plastic molding technology, be it that the conventional melting technology thereof is often developed for receiving and melting granulate material rather then filament material. In the respect of a 3D printer departing from the use of filament material as presently at stake, CN104647751A of May 2015 discloses a heat conductive material attached on the inner side wall of the hole passing through a heating block of the print head and the center of the nozzle. In the annexed figure, plastic string 1 may be noticed, fed by extruder 9 into a heater block 3, feeding molten plastic into a nozzle 4.

The plastic heating system is improved by the insertion of a “plate heater 7” in a “heating chamber” having internal copper walls and external insulating material 3. Where the application of the plastic heating system may be shaped or described differently, the underlying problem of uniformly melting plastic for a subsequent application or use thereof in molten form is a generic one of melting and is in many cases essentially not solved differently than already known from this CN publication. One example of such may e.g. be the embodiment of WO2016047732, published 31 march 2016, which teaches to provide the hole with a division into a large centralized hole section and a lower section (3) with multiple holes (see Figure 5). While the latter publication is dedicated to 3D printing, it in fact utilizes known solutions of uniformly melting plastic in a manner of a straight forward carry over of existing technology to 3D printers.

Another, generic example of a 3D printer system coping with the necessity of melting a filament of material may amongst others be found in US9233506 relating to a liquefier assembly for use in additive manufacturing system. Other embodiments as known from

CNI105034381A, may divide a filament receiving chamber of relative large size compared to the filament cross section, in several sections separated by sieve like element, called filter, for holding back larger and by subsequent filters, smaller non molten chunks of filament. US patent 20140328964 suggests the use of “channel surface morphologies” such as multiple port injection, angled channels, as well as fluted or spiral groove morphologies.

[0007] Other publications such as that of CN206141113U seem to seek high throughput, at least propose to enter a melting chamber via multiple filament entries, the chamber suggested to be large in diameter compared to the filament, at least entry openings.

Retraction dripping being a known problem in 3D printers, especially a high throughput printers, the melt chamber of this known print head is provided with a spring loaded closure element, opening and closing the melting chamber towards a nozzle chamber.

Such opening and closing valves are in itself known, e.g. from patent publications

CN207643704, also operating an in this case ball shaped valve by way of a spring, and

CN105459397A which illustrates a print head to be provided with an actuator element for a horizontally moving valve blade.

[0008] Further, a high throughput print head is indicated to be achievable in the publication *”’Ali-express Super3d - 3 in 1 out V6 Bowden remote J-head hot end kit without fan Brass Diamond 0.4 Nozzle” of May 17, 2021, depicting a single opening nozzle made in brass, teaching to have a multi-fiber 3D print head by having three print heads debouching in a single nozzle, with the print heads entering the nozzle at an angle relative to the central axis of the entire print head. Yet another proposal towards a fast printing head is provided in the article 'HOTENDS, new Products, Nozzles / Finish your print quicker than ever before, the volcano has erupted’ of march 28 2019. This result is indicated to be achieved by a print head, the Volcano Block with a relatively large height dimension, so as to provide for an elongated melting channel, indicated to have superior throughput. It is regarded however that none of the proposals provides a real high throughput print head, almost matching the output of so-called pallet printers, however still light weight, so that it can be handled by relatively small, at least relatively low cost

3D filament printers, not requiring the robotic volume and robustness, hence costs of a pallet printer. Where stretched melting chambers, sometimes up to 60 mm of height may cause vulnerability in case of unintentionally hitting a object with its lower end, up to destroying its heat break, the present invention further seeks to circumvent at least some of above indicated disadvantages in a robust, i.e. not too high and preferably light weight 3D print head system.

[0009] In the present invention various essential improvements have been made to the known 3D printer, both in various constituent parts which have been elucidated in the description and, as will become clear may often also be applied independently from one another, in many types of 3D printer, and methods of 3D printing. All in view of promoting either or both of the speed and the quality of printing.

[0010] In particular, the invention relates to a 3D-printer system, such as a 3D printing device based manufacturing system, comprising a 3D printing device, in which a filament of printing material is driven into a printer head, so as to be expelled therefrom in molten form, the printer thereto comprising a so-called filament extruder, which feeds the filament to the printer head, and the printer head comprising a heat block with heating means and filament receiving chamber and/or bore into which the filament is to be driven and in which the filament, during passage towards an end, such as a distal end of the heat block for delivery of filament material, is transformed into a molten, at least weakened, preferably plastically deformable state, and wherein the filament is guided in between the extruder and print head by a guiding tube provided with external tube-support means, the external tube support means being in the form of a sleeve, in which sleeve the guiding tube is fittingly received freely moveable, which sleeve is connected at each end to a socket for connecting tube support means to the extruder and to the print head respectively, and in which the guiding tube is freely moveable relative to a socket.

[0011] The tube support means either constitutes or comprises a tensile release element for the filament guiding tube. It is to be remarked that both the guide tube and the sleeve are flexible, alternatively denoted are of a flexible nature. Also, the sleeve, in the new concept preferably may rotate independently from preferably each of its end connections, which in this case are threaded. An end face of the guiding tube may abut a part of the extruder or the print head as the case may be, to which it is connected. The socket may be provided with a threaded end part for screwed connection with a receiving part of the extruder or print head. The filament guiding system between extruder and print head is adapted of being mounted pre-tensioned. The socket is provided with a recessed section for receiving a clamp, clamping the sleeve onto the socket. The sleeve may be a braided structure. The sleeve is a braid in any one of PVC fibers, Stainless steel, denoted RVS wire and Carbon fibers, denoted CF.

[0012] The invention hence encompasses a 3D Printer provided with a filament guiding tube embodied with one or more features as provided in anyone of the preceding 3D printing system clauses, a filament extruding and/or print head system comprising a filament guiding tube embodied with one or more features as provided in any the preceding. The new filament system and 3D- printer system preferably is provided with an extruder in the form of a so-called bladed or knife extruder, in which the extruder drives the filament by way of knife parts cutting into the filament and driving the filament by way of the knife blade, as it were with a tangential force exerted from within the filament.

[0013] The new system may further favorably be elaborated upon, in that the print head may be made of a system diverting a filament from a filament receiving print head part into a plurality of bores towards a distal end for central expelling of molten, at least softened filament material. The print head may herein also be adapted for receiving a plurality of filaments, each filament preferably expelled via a plurality of bores, and all filament material preferably debouching into a common chamber for central depositing of material. The invention also encompasses a filament guiding tube embodied in accordance one or more features as provided in any of the in the preceding presented 3D printing system features.

[0014] The invention may hence further encompass a 3D printer, in particular for a 3D printing based manufacturing system in which a filament of printing material is driven into a printer head, so as to be expelled therefrom in molten form, the printer head comprising a heat block provided with a filament receiving chamber into which the filament is to be driven, and in which the filament during passage through the chamber towards an end, such as a distal end of the heat block for delivery of filament material, is to be transformed into a molten, at least weakened, preferably plastically deformable state, and in which multiple filaments are received by a single heat block, the heat block provided with multiple filament receiving chambers, a receiving chamber transitioning into multiple channels, the channels each debouching from the heat block into a nozzle chamber. In this manner the print head remains both light weight and with a high throughput. The nozzle chamber may be formed between a distal end of the heat block and a nozzle element. The nozzle may be provided with a threaded connection part, design so as to engage said distal end circumferentially. Each filament receiving chamber transits into multiple channels included around a central channel, and the channels may be straight bores. The distal end of the heat block is designed to at least largely follow the contours of the nozzle wall, forming part of said nozzle chamber. The distal end of the heat block is provided with a central tip, which at least partly, e.g. by the end point of a conical shaped tip, extends into the central discharge opening of the nozzle. In particular the distal end of the heat block is provided with a cylindrically shaped central tip which at least partly extends into the central discharge opening of the nozzle.

[0015] The invention yet further claims a 3D printer, in particular for a 3D printing based manufacturing system in which a filament of printing material is driven into a printer head, so as to be expelled therefrom in molten form, the printer head comprising a heat block provided with a filament receiving chamber into which the filament is to be driven and in which the filament, during passage through the chamber towards an end, such as a distal end of the heat block for delivery of filament material, is to be transformed into a molten, at least weakened, preferably plastically deformable state, the receiving chamber comprising of one or more sections subsequently included, in which at least one section of the receiving chamber is provided with grooves, the grooves being included at an angle with the axis of the chamber. With such a measure, the filament material, as weakened on the outside is mixed with, if not scraped apart from a core part of material that may not yet have been in contact with the heating chamber wall, and the printing process may remarkably be sped up, in that the passage of the filament and filament material through the print head is promoted by at least a scraping effect caused by the angle under which the grooves are included, and as is presumed, possible also by a mixing effect thereof. In a favorable embodiment the grooves are provided in a second section of the chamber as taken in the direction of filament entry towards exit of weakened filament, allowing the filament first to be heated up and weakened, at least on the outer side, thereby not only lowering resistance in feed through of the filament, but also causing the scraping of and mixing to take place at some distance from the entry-point, thereby preventing that soft material may easily creep upwards, at least to escape from junctions at entry point of the filament.

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[0016] It is remarked that the receiving chamber in the invention, taken in cross section, at least largely is to correspond in dimension and shape with the cross section of the filament to be received, so as to thereby realize maximum of the desired and in accordance with the invention foreseen effect. In this respect it is also favorable that a first section of the chamber closely surrounds the filament received, typically forming a closely surrounding cylindrical section.

[0017] In again further elaboration, the receiving chamber merges into a final section of the heat block, provided with multiple channels, connecting the receiving chamber with the end of the heat block. In this manner the melting or alternatively denoted weakening, in particular homogeneous weakening, and hence plastic deformability of filament material is even further optimized in that, and preferably a significant number of relatively small channels each provide an optimal surface to content or volume ratio for this purpose, thus further enhancing both capacity and quality of a printer according to this invention.

[0018] Itis remarked that the preceding matter may be and is herewith reserved for independent claiming from the groove feature of this invention. Adding the grooves is more complicated and hence somewhat more expensive, however considerably increases the capacity of the printer, in that without the groove action, the capacity may become reduced to even about 40% of that with the grooves. The quality effect as described remains however, so that the channels, i.e. bores as disclosed in this invention are reserved for claiming in connection with a receiving chamber not having the grooves.

[0019] Favorably, the channels are formed by straight bores, so that manufacture is enhanced in that the bores may be favorably entered from the distal end of the heat block.

In this invention, the bores in the heat block may preferably be included radially diverging. Independently of the preceding, the bores are in a plane transverse to that determined by the radial diverging, included under an angle with the axis of the receiving chamber. Preferably and economically, the throughput enhancing grooves as presented before are formed by an end section of a bore. In yet further sophistication of the printer, part of the channels is formed by bores connecting with the end of the receiving chamber, e.g. the end of a second, grooved section.

[0020] The 3D printer of this invention may also be characterized by a feature in which the bores end distributed around a central core of the heat block. In particular, the central core is of a cross section larger in size than that of a bore. In this, preferably the bore ends as taken in end view, are provided at least substantially equally distributed in a regular shape, in particular within a circular shape, concentrically positioned relative to the axis of the chamber.

[0021] The here improved printer may favorably feature a heat block provided with a nozzle, the nozzle provided with a receiving chamber for receiving material expelled by the heat block and guiding the same to a central discharge opening of the nozzle. Herein the receiving chamber of the nozzle may be provided with a generally conical shape pointing away from the heat block end.

[0022] It is remarked that a printer in accordance with this invention may feature a heat block provided with and heated by cylindrically shaped heat elements, included in parallel with the chamber axis and extending over the largest part of the axial length of the heat block. Such measure supports, if not enhances the homogeneous weakening of the filament material to be deposited. A heating element hence preferably extends over at least substantially the entire axial length of the receiving chamber. The heat block may best comprise at least three of the coaxially included heat element, regularly distributed around the receiving chamber.

[0023] The nozzle mentioned before is provided for adhering to the heater block, e.g. via connecting, i.e. screwing or gluing and end face to a corresponding end face of the heat block. It may also have a screw thread provided to the outer side, i.e. circumference of an end part of the heat block, thereby enveloping, i.e. axially overlapping with at least an end part of a heater element. In an actual embodiment, the nozzle is provided with an end face for contacting a distal end of the heat block, the heat elements of the heat block being provided to extend virtually up to the end face.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Various aspects of the invention and an example of part of an embodiment of the invention is illustrated in the drawings which depart from the general and wide spread knowledge of 3D printing system and extruders therefor, and in which:

[0025] FIG. 1 schematically represents a possible 3D printer device of a 3D printing system as may typically be improved by including a solution according to the the present invention;

[0026] FIG. 2A represents an extruder system according to the present invention comprising a filament feeder system, in this case a knife blade extruder; a print head system, in this case capable of expelling large volume of material to be deposited; and an armored, at least tensile re-enforced filament guiding tube system connected between feeder and print head, while FIG. 2B represents various types of armor for use as a sleeve to a known per se filament guiding tube;

[0027] FIG. 3A to 3D provide perspective views and cross sections of a filament guide tube in accordance with the present invention, with the end part thereof provided in close up;

[0028] FIG. 4 represents an elaborated feature for the filament guide tube of FIG. 3, in that the sockets are adapted to allow for free rotation of the tube relative to a socket: a cross section and a perspective view are provided in axial cross section and in perspective view by FIG. 4A, 4B and 4C, 4D for a male and a female socket respectively ;

[0029] Figures SA to 5B illustrate various cross sections of the principle of a print head and heater block as may favorably be applied with the invention, i.e. adapted for high throughput of printing material;

[0030] FIG. 6A to 6H in subsequent locations between an entry point of a print head and it’s distal end illustrate the principle of FIG. 5 by cross section at various height levels of the print head.

[0031] FIG. 7A to 7F illustrate various views and aspects of one proposal towards a new concept design and embodiment for a high throughput printer;

[0032] FIG. 8A to 8F provide, in a manner comparable to that of FIG 7, yet another embodiment and conceptual design of the invention;

[0033] FIG. 9A and 9B only partially provide a design, otherwise in line to FIG. 5 or

FIG. 6, of yet a further development and concept according to the present invention.

[0034] The invention will in the following still by way of example now be described more in detail.

[0035] FIG. 1 and further disclose a method of operating a 3D printer of a 3D printing based manufacturing system 1 in which a filament of printing material is driven into a printer head, in which the filament is driven into a printer head so as to be expelled therefrom in molten form, the method and system comprising the steps of driving the filament into a heater block thermally separated from a feeder element by means of a connection between feeder element and heating block centrally comprising a thermally isolating separator or distance member through which the filament is fed. The present invention may in principle be applied with any type of 3D printers, including so-called delta type printers. FIG. 1 in this respect discloses a per se equally well known Cartesian type of 3D printer, with a filament feeder 2 shown to be connected to an upper frame member. The feeder 2 connected via a guiding tube to a print head with filament heater, inthe 3D printer system movingly activated along an X- and a Y-axis or guide beam. The filament is herein fed by the feeder through the guiding tube to the often denoted Bowden cable to the print head and its heater block.

[0036] FIG. 2A depicts a filament delivery subsystem of the latter 3D printer more in detail, with a feeder 2 provided with an electric drive motor, a print head 3 including amongst others. a heater block and nozzle, and in between a guiding tube 4, in this case provided armored, i.e. re-enforced or supported by a fitting sleeve of a braided material, preferably diagonally braided. The sleeve 4 is at its ends fastened to an end connector or socket via a surrounding fastener 6.

[0037] FIG. 2B indicate filament guiding tube supporting means according to the present invention, in the form of sleeves made with fibres or wires of carbon, PVC or metal material as seen from left to right and providing or accommodating a tensile release function to the filament guiding tube in conjunction with a socket as indicated in figures 3 and 4. FIG. 2B depicts various types of braided sleeves, with from left to right Carbon fiber braid, PVC braid, representing the most flexible sleeve of the three tested sleeves, and to the right RVS, the least flexible in nature, produced with stainless steel. All three types have been tested upon extension of the guiding tube relative to its normal, i.e. unloaded state, in dependence of the force, in the below table expressed in “Newton”, exerted by a feeder 2 within the subsystem, so as to express the percentage of elongation of the guiding tube, both standard, i.e. without sleeved, and in sleeved states for PVC,

RVS and CF sleeve materials respectively.

Newton Standard PVC RVS Carbon fibre 090% 110% 0,10% 0.07% 100 200% 180% 0.40% 0,13% 150 540% 2,50% (0.65% 0.20% 200 1490% 310% 0,85% 0,25% 250 4360% 4.00% 089% 0,31%

[0038]

[0039] It is clear from the table that standard guiding tubes may still perform quite well at a pressure level of SON as may be exerted by an ordinary type of feeder, and even at 100N as in the case of somewhat faster printer systems.

That is, the elongation is not that great, be it depending of the length of the guiding tube, that so called oozing or dripping of material on the work piece can no longer be prevented by normal retraction of the filament by the feeder 2. The technique of retraction is applied for quick jumps of the print head over the work piece, without needing additional mechanical shutters which need to be controlled to act in symphony with the start and end of the jump to be performed, and which apart from costs, add complexity in electronic control and an added risk of in mechanical and electronic failure.

It is also clear that fitting a standard filament guiding tube with a braided sleeve generally provides improvement both at the force levels exerted by “domestic grade” feeder elements and at higher force levels of 150 N and above, as may typically be used in professional or semi-professional equipment, while still being able to utilize the retraction method during certain printing moves, i.e.

without a need for complicated shutters.

After all, when fitted with sleeve, the guiding tube elongation, even a 250 N may be comparable to or lower than at applying a standard, non-sleeved guiding tube at lower levels of filament feeding force.

In order to be able to expel the filament at such pressure levels, i.e. in conjunction with a sleeved guiding tube, in a proper state of plasticity of the material, the invention has further foreseen to combine a sleeved feeding or guiding tube with a print head having multiple channels branching from a receiving chamber in the heat sink part of the print head.

In this manner a very large output may be attained with the proper grade of liquidity of evenly molten filament, while still being able to utilize the normally promptly responding retraction technique, both for reason that the elongation is within a practicable absolute range in mm of to be retracted filament, and for reason that the output, despite the splitting into multiple channels, can still be performed by the same filament feeder and feeding tube.

In general the invention recognizes that the highest forces may not be applied, i.e. that the highest printing speeds may be not or may at improper quality be attained, especially due to insufficient or un-even melting, if the sleeve is applied in combination with an ordinary print head.

The present invention holds that a guiding tube sleeved in accordance with the present invention is applied in conjunction with a print head with a distributed melting channel feature, so as to optimally allow unfolding of a high throughput at high quality while still enabling for the application of the favorable retraction technique, in particular even with high quality result, in that the amount of elongation in the guiding tube, and hence the length of and response time in retraction may be maintained limited to practicable values without loss of quality.

[0040] FIG. 3A, in a perspective view of a sleeved guiding tube system 4 of the invention, indicates a securing means 6, e.g. a clamp or press fit, for securing a sleeve 4S to and end element 7, in this case a threaded socket. The sleeve 4S re-enforces, i.e. armoires a known per se, normally solely applied, flexible guide tube 8 for guiding a here not depicted filament from feeder 2 to print head 3. FIG. 3B is a cross sectional view of the system of FIG. 3A, showing the socket 7 according to preference to be provided with arecessed part at the end for receiving the securing means 5, and showing the guide tube 8 to extend through both the sleeve 4S and the sockets 7. FIG. 3C is a close-up of a socket part of the guide system 4, indicating a threaded outer end of a socket 7, and a part of guide tube 8 extending preferably at least somewhat beyond a socket 7, so as to be received by, and to abut and end face of either of feeder system 2 and printing head system 3, FIG. 3D providing a cross sectional view of the close up of FIG. 3C.

[0041] Figure 4 provides elaborations of the socket 7 of FIG. 3, in a so-called male and female version, in a development allowing independent rotation of a guiding tube 8 and any armouring sleeve 4S therefor, relative to a socket. In the case of the male socket as depicted in a longitudinal cross section in FIG. 4A and in perspective in FIG. 4B, an e.g. threaded connection end part 11A, is provided freely rotatable around a guide tube receiving part 11A, here provided with an end section extending beyond the connecting part 10A, in this case partly recessed, so as to allow securing of a sleeve thereto. The tube receiving part 10A is at its other end provided with a notch 12A, to which the end face of connection part 11A may abut, thereby allowing axial fixation of the tube receiving part 10A upon connection of the socket in an extruder system. In a corresponding manner FIG. 4C and FIG. 4D provide the so-called female version of this free rotation allowing embodiment of a socket 7. It may be clear that the connection face, in this case a threading for allowing a screw connection, of the socket version of FIG. 4C and 4D is included at the inner side a connection part 11B. An abutting face 12B is here provided at both the guide tube receiving part 10B and to the connecting part 11B, here at an inward facing side thereof.

[0042] Further, at the heater block, as schematically depicted in FIG. 5A and 5B, by including a thermally not or minimally conducting distance holder in the feeding or entry path of the filament, the invention realizes that the heat path to which the filament is subjected is effectively elongated, i.e. the filament is instantly brought into contact with a heater block part of a maximum possible temperature level. Hence this measure increases the melting capacity of the heater block, and therewith improves both quality and speed of the print head.

[0043] Yet a further, in fact also independently applicable measure according to the present invention holds the receiving and heating of the filament in a first receiving section included as a common chamber for receiving filament and filament material, and subsequently dividing the filament material within a second, further filament receiving section of the heater block into separate streams of material. With such a method of 3D printing and with a 3D printer adapted thereto, high heating temperature may be attained as well as a controlled transition from solid filament stage to a gradually melting at least due to increased temperature environment, softening of the filament. This softened filament may be pressured further into separate channels where the material may be heated through and through since the thickness of the material relative to the surrounding heat wall is much more favorable than in in the first section. This is unlike many prior art designs where the core of the filament may still be unmolten or partially molten, at least not as fluid as in the circumferential parts of the filament to be spelled out.

[0044] An optimizing feature in accordance with the preceding holds that the inner wall of the first receiving section is provided with grooves spiraling towards the lower end of the section. In this manner the partly heated filament may already mechanically be somewhat mixed or split up, especially if more than one grooves is carved or otherwise at least largely shaped. An even further improvement in pre-mixing and flow of heated if not largely molten plastic is attained if the grooves each spiral towards an opening in the second receiving section for realizing said separate streams.

[0045] According to yet a further and in fact also independently applicable method step, the heated material is expelled from the heater block via a printer nozzle, receiving said separate streams and recombining the same for at least in part, the nozzle thereby maintained in intimate thermal contact with said heater block. In this manner it is assured that final mixing is with certainty performed on thoroughly softened if not molten material, since all expelled from a relatively small diameter heater channel, and since the nozzle itself in fact is virtually integrated with the heat block due to its large, circumferential and screwed thermal contact with the block. In that manner it is assured that the thoroughly heated material will not solidify at arriving in contact with a nozzle which in prior art design may be found to be of relatively lower temperature, e.g. due to the nozzle normally be screwed to an inner thread of the heater block. The nozzle according to the invention is hence provided for adhering to the heater block via screw thread provided to the outer side, i.e. circumference of an end part of the heater block. In this manner the thermal contacting surface may, with the thread even further be increased. Yet another measure to the nozzle, in fact to even further support the latter heat effect, holds that tightening of the nozzle to the heater block causes an end face of the heater block to intimately contact an at least largely corresponding, opposing face provided within the nozzle, therewith further increasing the thermal contact between heater block and nozzle. Where the latter is made of a messing type of material, internal transfer of heat is optimized.

[0046] It is remarked that in a further development of the method in accordance with the invention, the thermally separated connection between feeder element and heating block comprises radially outward disposed screws, firmly connecting the feeder element to the heater block, of course under maintaining the pre-mentioned thermally decoupling mechanical distance holder. Where the latter may be made of a composite or ceramic material, the screws are of a stainless steel, may be maintained relatively small so as thereby equally minimizing heat transfer over the screws. Where any local loss of heat level could be remarked, this will in the present, new design be relatively remotely from the central section housing and heating the filament, thereby maintaining a relatively high temperature at entry of the filament, at least temperature wise favorable condition, when compared to prior art designs. So as to promote this remoteness of a potential heat bridge, the three screws are regularly distributed disposed for said firm connection, preferably the screws incorporated in a flange-like part for the feeder element. A favorable side effect of this design is that simultaneously the rigidity or bending stiffness in the connection between feeder element and heating block is optimized, if not improved relative to many prior art designs. The presently discussed feature may hence, whether or not even only for the latter advantage, or in conjunction with or solely for the thermal effect, hence also be applied either in conjunction with the preceding for further optimization, but also independently.

[0047] In yet a further development of the present invention, and also equally independently applicable measure, the heater block is included in the print head in a manner surrounded by a standing volume of air. In this manner, despite continuous movement of the print head a continuously stable thermal environment is created for the heater block, increasing its capacity to maintain a high and constant heat level, therewith increasing controllability of the printer head and of the printing process, in particular both the speed and the quality thereof. In a most favorable embodiment, this feature is realized by having the a volume of standing air surrounding the heater block provided by way of a heat sink included in the print head circumferentially to the heater block.

Another important effect of having the heat sink circumferential to the heater block rather than preceding it, is that the height of the heater block may relatively easily be increased, therewith allowing for even further improvement and control of the melting process of a filament at entry thereof into the heater block. Also for this reason alone the heat sink may be included circumferentially to the heater block.

[0048] In a further development of the latter, the surrounding heat sink is closed to its upper distal end by an upper wall. An upper wall part of the heat sink may form a flange part to the feeding element. In such design, the feeder element favorably is centrally screwed into an upper wall part of the circumferential heat sink.

[0049] Further to the preceding it may be noted that the feeder element is favorably formed by a mainly tubular or prismatic part, abutting to the thermally isolating distance member by a distal end face. Internally, in a preferred embodiment the inner channel thereof may at some point or gradually be formed tapered. The feeder element preferably is further secured in the print head by way of a counter acting nut, screwed to the outer side of the tubular part and abutting the flange like part to which the feeder element is secured, e.g. by the part being screwed into the flange like part via an inner screw thread thereof.

[0050] In a further favorable development of the method according to the invention, the heat sink is produced in an aluminum material, keeping inertia forces down for as far as increased by the more remote positioning of the weight of the heat sink. Equally if not more important is that the heater block is in the present invention also produced in aluminum. It was recognized that with the preceding measure of the invention, to generally raise and equally distribute the heat within the heat block, the filament material becomes soft in a much earlier stage, therewith reducing both internal resistance, even when in fact increased to some extend by the splitting thereof into separate streams, as well as its abrasive effect. It is for this reason recognized that the heat block may be produced in aluminum material. This is all the more so if at least part of the inner wall of anyone of the chamber sections is provided with a diamond, in particular nano-diamond coating. Maintaining a low weight in the print head supports swift and smooth manipulation and movement of the print head and therewith speed and quality as performance factors of a print head.

[0051] In yet a further development the heater block is provided in a two part form comprising of a circumferential outer block part provided with receptacles for electric heater elements, and a central inner part provided with said first and second section receiving chambers. Preferably and favorably, the central portion is screwed into the outer portion, hence may be released, i.e. taken away therefrom e.g. for replacement, the portions thereto being provided with inner and outer screw thread respectively.

[0052] In yet a further development if the method of 3D printing, in accordance with the present invention, the heater block is provided with at least one heat sensor. This measure allows for improved control of the printer characteristic, in that the temperature may be maintained relatively low if relatively slow printing speeds are desired for any particular section of a work piece, e.g. for high quality or accuracy, and relatively high where large volumes of material may be expelled, e.g. for reason that quality may locally not be of concern or be guaranteed also under such increased printing speeds. The printing method is even further improved in that the 3D printer system of the present invention is provided with a pressure sensor. This may be for directly or indirectly sensing feeding pressure of the filament. Where such a sensor could e.g. also be included in the extruder of the filament or to a motor shaft thereof, it may also be the case that a receiving chamber or receiving chamber part is provided with a pressure sensor. A major advantage of having such pressure sensor is not only in controlling delivery of a constant stream of material and at certain pressure, but also the possibility to timely control towards a so-called retraction action of the filament, in which, at jumps over the work piece, no material is meanwhile expelled as in prior art designs or leaked at such instance, so that with certainty clean work may be delivered at all times.

[0053] It hence goes without saying that the 3D printer according to the present invention is provided with a controller controlling pressure and temperature in conjunction, i.e. as a function of the local nature of the work piece to be printed, and that different parts of a work piece may be printed with different speed, volume of flow and/or temperature of delivery.

[0054] The invention is in the following alternatively describe by way of a set of clauses, indicating features of the present invention that sometimes may in principle improve a 3D printer on it’s own, but which often give best results if applied with at least a number of the features included jointly in a 3D printer.

1. A method of operating a 3D printer of a 3D printing based manufacturing system in which a filament of printing material is driven into a printer head, in which the filament is driven into a printer head so as to be expelled therefrom in molten form, the method comprising the steps of driving the filament into a heater block thermally separated from a feeder element by means of a connection between feeder element and heater or heat block centrally comprising a thermally isolating separator or distance member through which the filament is fed.

2. A method of operating a 3D printer in accordance with the preceding clause, receiving and heating the filament in a first receiving section included as a common chamber for receiving filament and filament material, and subsequently dividing the filament material within a second, further filament receiving section of the heater block into separate streams of material.

3. Method in accordance with the preceding clause, in which the inner wall of the first receiving section is provided with grooves spiraling towards the lower end of the section.

4. Method in accordance with the preceding clause, in which the grooves each spiral towards an opening in the second receiving section for realizing said separate streams.

5. Method in accordance with any of the preceding clauses in which, in a further step the heated material is and expelled from the heater block via a printer nozzle,

receiving said separate streams and recombining the same for at least in part, the nozzle thereby maintained in intimate thermal contact with said heater block.

6. Method in accordance with the preceding clause, in which the nozzle is provided for adhering to the heater block via screw thread provided to the outer side, i.e. circumference of an end part of the heater block.

7. Method in accordance with the preceding clause, in which tightening of the nozzle to the heater block causes an end face of the heater block to intimately contact an at least largely corresponding, opposing face provided within the nozzle.

8. Method in accordance with any of the preceding clauses, in which the thermally separated connection between feeder element and heater, alternatively denoted heat block comprises radially outward disposed screws, firmly connecting the feeder element to the heater block.

9. Method according to the preceding clause, in which three, regularly distributed screws are disposed for said firm connection, preferably the screws incorporated in a flange-like part for the feeder element.

10. Method according to any of the preceding clauses, in which the heater block is included in the print head in a manner surrounded by a standing volume of air.

11. Method according to any of the preceding clauses, in which a volume of standing air surrounding the heater block is provided by way of a heat sink included in the print head circumferentially to the heater block.

12. Method according to any of the preceding clauses in which an upper wall part of the heat sink forms a flange part to the feeding element.

13. Method according to any of the preceding clauses in which the feeder element is centrally screwed into an upper wall part of the circumferential heat sink.

14. Method according to the preceding clause in which the feeder element is formed by a mainly tubular or prismatic part, abutting to the thermally isolating distance member by a distal end face.

15. Method according to any of the preceding clauses, in which the feeder element is further secured in the print head by way of a counter acting nut screwed to the outer side of the tubular part and abutting the flange like part to which the feeder element is secured, e.g. by the part being screwed into the flange like part via an inner screw thread thereof. 16. Method according to any of the preceding clauses in which the heat sink is produced in an aluminum material.

17. Method according to any of the preceding clauses, in which the heater block is produced in aluminum.

18. Method according to the preceding clause, in which the at least part of the inner wall of anyone of the chamber sections is provided with a diamond, in particular nano-

diamond coating.

19. Method according to any of the preceding clauses, in which the heater block is provided in a two part form comprising of a circumferential outer block part provided with receptacles for electric heater elements, and a central inner part provided with said first and second section receiving chambers. 20. Method according to the preceding clause, in which the central portion is screwed into the outer portion, the portions thereto being provided with inner and outer screw thread respectively. 21. Method in accordance with anyone of the preceding clauses, in which the heater block is provided with at least one heat sensor. 22. Method in accordance with anyone of the preceding clauses, in which the 3D printer system is provided with a pressure sensor for directly or indirectly sensing feeding pressure of the filament. 23. Method in accordance with any of the preceding clauses in which a receiving chamber or receiving chamber part is provided with a pressure sensor. 24. Printer head specified with any one or more of the methods steps and print head elements as specified in anyone of the preceding clauses. 25. Printer according to the preceding invention provided with a controller controlling pressure and temperature in conjunction, i.e. as a function of the local nature of the work piece to be printed. 26. Printer according to any of the preceding printer clauses, in which different parts of a work piece may be printed with different speed, volume of flow and/or temperature of delivery.

Further definitions or clauses equally describing and defining the invention may be as follows. 1. 3D printer, in particular for a 3D printing based manufacturing system in which a filament of printing material is driven into a printer head, so as to be expelled therefrom in molten form, the printer head comprising a heat block provided with a filament receiving chamber into which the filament is to be driven and in which the filament, during passage through the chamber towards an end, such as a distal end of the heat block for delivery of filament material, is to be transformed into a molten, at least weakened, preferably plastically deformable state, characterized in that multiple filaments are received by a single heat block, the heat block provided with multiple filament receiving chambers, a receiving chambers transitioning into multiple channels, the channels each debouching from the heat block into a nozzle chamber.

2. Printer in accordance with the preceding clause, in which the nozzle chamber is formed between a distal end of the heat block and a nozzle element.. 3. Printer in accordance with any one of the two preceding clauses, in which the nozzle is provided with a threaded connection part, designed so as to engage said distal end circumferentially. 4. Printer in accordance with any one of the preceding clauses, in which each filament receiving chamber transits into multiple channel included around a central channel. 5. Printer in accordance with any of the preceding clauses, in which the channels are straight bores.

6. Printer in accordance with any of the preceding clauses, in which the distal end of the heat block is design to at least largely follow the contours of the nozzle wall forming part of said nozzle chamber.

7. Printer in accordance with any one of the preceding clauses, in which the distal end of the heat block is provided with a central tip, which at least partly, e.g. by the end point of a conical shaped tip, extends into the central discharge opening of the nozzle.

8. Printer in accordance with any one of the preceding clauses, in which the distal end of the heat block is provided with a cylindrically shaped central tip which at least partly extends into the central discharge opening of the nozzle.

CLAUSES

1. A 3D-printer system, such as a 3D printing device based manufacturing system, comprising a 3D printing device, in which a filament of printing material is driven into a printer head, so as to be expelled therefrom in molten form, the printer system thereto comprising a so-called filament extruder or feeder, which feeder feeds the filament to the printer head, and the printer head comprising a heat block with heating means and filament receiving chamber and/or bore into which the filament is to be driven and in which the filament, during passage towards an end, such as a distal end of the heat block for delivery of filament material, is transformed into a molten, at least weakened, preferably plastically deformable state, in which device, the filament is guided in between the extruder and print head by a guiding tube provided with external tube-support means, characterized in that the external tube support means are in the form of a sleeve, in which sleeve the guiding tube is fittingly received freely moveable, which sleeve is connected at each end to a socket for connecting tube support means to the extruder and to the print head respectively, and in which the guiding tube is freely moveable relative to a socket. 2. System according to clause 1, in which the tube support means either constitutes or comprises a tensile release element for the filament guiding tube. 3. System according anyone of clauses 1 and 2, in which both the guide tube and the sleeve are of a flexible nature. 4. System according anyone of clauses 1, 2 and 3, in which an end face of the guiding tube abuts a part of the extruder or the print head as the case may be, to which it is connected. 5. System according to anyone of the preceding clauses, in which the socket is provided with a threaded end part for screwed connection with a receiving part of the extruder or print head. 6. System according to any of the preceding clauses, in which the sleeve is incorporated rotatable independently from its fixation to e.g. threaded end points. 7. System according to anyone of the preceding clauses, in which the filament guiding system between extruder and print head is adapted of being mounted pre- tensioned.

8. System according to any of the preceding clauses, in which the socket is provided with a recessed section for receiving a clamp means including a so-called press fit, clamping the sleeve onto the socket. 9. System according to anyone of the preceding clauses, in which the sleeve is a braided structure. 10. System according to anyone of the preceding clauses, in which the sleeve is a braid in any one of PVC fibers, Stainless steel (RVS) wire and Carbon fibres. 11. 3D Printer provided with a filament guiding tube embodied with one or more features as provided in any of the preceding 3D printing system clauses.

12. Filament extruding system comprising at least one of a filament feeder and a print head system, adapted for receiving or provided with a filament guiding tube embodied with one or more features as provided in any of the preceding 3D printing system clauses,

13. Filament system in accordance with the preceding clause, in which the feeder element is a so called bladed or knife extruder, in which the extruder drives the filament by way of knife parts cutting into the filament and driving the filament by way of the knife blade.

14. Filament system in accordance with any of the two preceding clauses, in which the print head is of a system diverting a filament from a filament receiving print head part into a plurality of bores towards a distal end for central expelling of molten, at least softened filament material.

15. Filament system in accordance with any of the three preceding clauses, in which the print head is adapted for receiving a plurality of filaments, each filament preferably expelled via a plurality of bores, and all filament material preferably debouching into a common chamber for central depositing of material.

16. Filament guiding tube embodied in accordance one or more features as provided in anyone of the preceding 3D printing system clauses.

Claims (16)

CONCLUSIONS 1. A 3D printer system, such as a manufacturing system based on a 3D printing device, comprising a 3D printing device, in which a filament of printing material is driven into a printer head in order to be ejected therefrom in molten form, the printer system comprising a so-called filament extruder for this purpose includes at least a feeder, which feeds the filament to the print head, the print head consisting of a heat block with heating means and a filament collecting chamber and/or bore into which the filament is to be driven and into which the filament during passage to an end, such as a distal end of the heat block for delivery of filament material, is converted into a molten, at least weakened, preferably plastically deformable state, in which device the filament is guided between the extruder and print head through a guide tube provided with external tube supporting means, characterized in that the external tube supporting means have the form of a sleeve, in which sleeve the guide tube is accommodated in a freely movable manner, which sleeve is connected at each end to a sleeve for connecting tube support means to the extruder and to the printhead, and wherein the guide tube is freely movable relative to a sleeve . The system of claim 1, wherein the tube support means forms or includes a strain relief element for the filament guide tube. A system according to any one of claims 1 and 2, wherein both the guide tube and the sleeve are flexible in nature. The system of any of claims 1, 2 and 3, wherein an end face of the guide tube abuts a portion of the extruder or print head, as the case may be, to which it is connected. A system according to any one of the preceding claims, wherein the sleeve is provided with a threaded end portion for screw connection to a receiving portion of the extruder or print head. 6. A system according to any one of the preceding claims, wherein the sleeve is mounted rotatably independently of its attachment to, for example, threaded end points. 7. System according to one of the preceding claims, in which the filament guide system between extruder and print head is designed to be mounted prestressed. A system according to any one of the preceding claims, wherein the sleeve is provided with a recessed portion for receiving a clamping means, including a so-called press fit, which clamps the sleeve onto the sleeve. System according to any of the preceding claims, wherein the sleeve is a braided structure. A system according to any one of the preceding claims, wherein the sheath is a braid in which one of PVC fibers, stainless steel wire and carbon fibers. 11. 3D printer provided with a filament guide tube embodied with one or more features as provided in one of the preceding 3D printing system claims. A filament extrusion system comprising at least one of a filament supply and a print head system adapted to receive or provide a filament guide tube embodied with one or more features as provided in any of the preceding 3D printing system claims. Filament system according to the preceding claim, wherein the feed element is a so-called knife or knife extruder, the extruder driving the filament by means of knife parts that cut into the filament and drive the filament via the knife blade. Filament system according to one of the two preceding claims, wherein the print head is a system that diverts a filament from a filament-receiving print head part in a number of bores to a distal end for the central expulsion of molten, or at least softened, filament material. A filament system according to any one of the three preceding claims, wherein the printhead is adapted to receive multiple filaments, each filament preferably being expelled through multiple bores, and wherein all filament material preferably exits into a common central deposit chamber of material. A filament guide tube embodied in accordance with one or more features as provided in any one of the preceding claims for a 3D printing system.