NL1043469B1

NL1043469B1 - Method, 3d manufacturing system and print head therfor

Info

Publication number: NL1043469B1
Application number: NL1043469A
Authority: NL
Inventors: Arnoud Korevaar Martijn
Original assignee: Veda Group B V
Priority date: 2019-11-19
Filing date: 2019-11-19
Publication date: 2021-08-11

Abstract

The present invention discloses 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 heating block centrally comprising a thermally isolating separator or distance member through which the filament is fed. 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.

Description

METHOD, 3D MANUFACTURING SYSTEM AND PRINT HEAD THERFOR Field and background of the Invention

[0091] 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 mammer of using or operating a print head. {00021 So called 3D printing based device manufacturing systems have been ont in the art ever since 1982, however have presently not only become popular in amateur or IO 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, 10003] 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, CN10464775 LA of May 2015 discloses a heat conductive material attached on the immer 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 “beating 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 aud is in wany 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 foand in US9233506 relating to a liquefier assembly for use in additive manufacturing system,

BRIEF SUMMARY OF THE INVENTION joond] In the present invention various essential improvements have been made to the known 3D printer, both in various constituent parts, which, gs will become clear muay often also be applied independently from one another, as well as to the method of cperafing such 3D printer, if not to a method of 3D printing, sil in view of promoting either or both of the speed and the quality of printing.

i

BRIEF DESCRIPTION OF THE DRAWINGS {0005} Various aspects of the invention and an example of part of an exabodiment of the invention iy usteated in the deawings which depart from the general and wide spread knowledge of 3D printing system and exiradess therefor, and io which: IS 0005] FRG. | schematically depicts a certain cross scctiemal view of a print head in accordance with the present invention; ooo] FIG, 2 is another cross sectional view of the san, farther clarifying the prim head design of the Invention doos] FIG. 3 illustrates from a perspective view the upper end of the heater in accordance with the present invention; oons) FIG. 4 analogously iHastrates the bottom distal ond thereof, with a print nozzle attached; ice) FIG. S schematically illustrates an invention acconling to which the filament receiving chamber of a heater block splits up into different channels for guiding and heating filament material; Doin FIG, 54 provides an external, perspective view of the preceding; josie) PRG. 6 and 8A, in a perspective view ilnstraie yet an other invention, here cooperating with the invention of FIG. 5, according to which the print nozzle is screwed to an external thread of the beater block, [omar PIG, 8A is provides the view with the nozzle removed, sad further iHustrates a preferred embodiment in which the beater block is split up into four separate channels debouching imo a normally conically shaped plenum of the here not depicted print nozzis;

3e

[0014] FIG, 7 illustrates yet another independently applicable invention and measure, according to which the heater block is split up info an outer section carrying electric heater elements and an inner, detacheable section in which the receiving sections for the filament to be Hquefied;

[0015] Figure 8 illustrates that the latter invention may be applied in conjunction with other inventions and measures mentioned here such as the invention in accordance with figure 5, the one measure thus becoming an aspect of the other, while still also independently being applicable if so preferred or desired; ome] FIG. 9 and FIG. 9A illustrate the latter design of figure 7 and 8 from different IQ perspective views.

{6017} BIG, 10 and 10A from an outer perspective view and from a cross sectional view lustrate the invention of providing a standing layer of air around the heater block, In particular by providing the heat sink circumferential to rather than in line with the heater block. As in gure | and 2, FIG. 10A also ijlustrates the invention of providing a thermally isolating distance member between the heat sink, be it the upper wall thereof, or the lower end thereof as in prior art designs.

[00187 FIG. 11 and TIA illustrate the latter design in a perspective view with an without the print nozzle attached, and also showing a measure to have the electric hoating elements partially protruding from, Le. through the outer heat block part: [00191 FIG. 12 illustrates an embodiment in which the heater block section accommodating the separate channels is designed of greater height that than the first section with central receiving chamber for the filament.

[0020] FIG. 124 illustrates the invention relating to the thermally decoupling distance member applied in an otherwise largely conventional printer head design 23 [0021] FIG. 13 illustrates the application of the invention of a standing layer of air, or circumferentially applied heat sink to an otherwise largely conventionally designed heater block.

[0022] FIG. 13A illustrates the application of circom{erentially distributed screws between heater block and feeder element in an otherwise conventionally designed printer head, as well as the measure of having in this case four electric heater elements protruding from the heater block; : {0023} FIG, 14 and 14A illustrate different perspective views of the design according to FIG. 13.

fos24} PIG, 1S Hustrates a print bead carrying system according to another aspect of the present invention according to which the print head is supported by what may be called a compliant joint, comprising npwardly extending hugs attached to the print bead, articulating with an intermediary block over a first axis, the hmermediary block acticulating with a sopport rod over a second axis oriented transverse to the first axis, both parallel to an bnagioary of previewed work piece ares, the invention taking away lag from the system; [00231 BIG 16 and 16A illustrate the same from a top and bottom view respectively, and both FIG. 15 and 15, slong with figure 1 iHustealing another aspect of the invention, in 1 which the print head sccommodates cooling or ventilation means, further controlling and improving the process and work piece to be delivered,

DESCRIPTION OF ILLUSTRATIVHE EMBODIMENTS ooze FRG. } and further disclose a method of operating a 3D printer of a 3D printing 18 bosed manufacturing system in which a filament of printing material is driven Imo 2 printer head, in which the filament is driven into a printer head so as to be expelled therefrom in molen form, the method comprising the steps of driving the filament into & heater block thermally separated from a feeder clement by means of a connection between feeder clement and heating block centrally comprising a thermally isolating separator or distance member through which the Element is Ted. By including a thermally not or mininally 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 19 effectively elongated, te. the filament is instantly brought into contact with a heater block part of a maximnm possible temperature level, Hence this measure increases the melting capacity of the hester block, and therewith improves both quality and speed of the print head. 00271 Yel a farther, in fact also independently applicable measure according to the present invention holds the receiving and heating of the filament in a fist recelving section included as a common chamber for receiving Hlament and filament material, and subseqgoently dividing the filament material within a second, further Slament receiving 3G section of the heater Hock Info 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 woll as 8 controlled transition from solid filament stage to a gradually melig al least due fs increased temperature environment, softening of the filament, This softened

5e 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 crumble at least not as fluid as in the 3 circumferential parts of the filament to be spelled out,

[0025] An optimising 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 10 the second receiving section for realizing said separate streams, 00291 According to yet a further, and in fact also independently applicable method step, the heated material is and expelled from the beater block via a printer nozzle, receiving iS said separate streams and recombining the same for at least in part, the nozzle thereby maintained in wtimate 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 Tact is virtually integrated with the heat block due to its large, circomierential and screwed thermal contact with the block, In that manner it is assured that the thoroughly heated material will not solidity at arriving in contact with anozzle 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, 1e. 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 beater block canses 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 matedal, internal transfer of heat is optimized.

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[00301 His remarked that in g farther development of the method In accordance with the invention, the thermally separated connection between feeder element and heating block comprises radially ontward disposed screws, firmly connecting the feeder clewent 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 conld be renmrked, this will in the present, new design be relatively remotely from the central section housing and heating the filament, thereby maintaining a relatively high

I 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 beat bridge, the three screws are regularly distributed disposed for said firm connection, preferably the screws incorporated in a Hange-like part for the feeder element.

A favorable side effect of this design is that simultancously the rigidity or bending stiffuess in the connection iS 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 later advantage, or In conjunction with or solely for the thermal effect, hence also be applied cither in conjunction with the preceding for further optimization, but alsa independently,

3h In yet a further development of the present vention, and also equally mdependently applicable measure, the heater block is included in the print head in a manner surroonded 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 IVs capacity to maintain a high and constant heat level, therewith increasing controllability of the printer head aud of the printing process, in particular both the speed and the goality 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 sllowing 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 circumfercatially to the heater block.

JJ [00321 In a further development of the latter, the surrounding heat sink is closed to it's 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 suk.

10033) Further to the preceding it may be noted that the feeder element is favorably formed by a mainly tobular 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 [0 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.

[00341 In a further favorable development of the method according to the invention, the heat sink is produced in an aluminum material, keeping centrifugal forces down for as far asivcreased by the more remote positioning of the weight of the heat sink. Equally if not mote 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 it's abrasive effect. It is Tor this reason recognized that the heat block may be produced in aluminam 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-diameond coating. Maintaining a low weight in the print head supports swift and smooth manipolation and movement of the print head and therewith speed and quality as performance factors of a print head.

[00351 In yet a further development the beater 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, 1.e. taken away therefrom e.g. for replacernent, the portions thereto being provided with inner and outer screw thread respectively.

[0036] In get 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 iapraved control of the printer characteristic, in that the temperpiare may be mautamed relatively low if relatively slow printing speeds are desired for any particalar section of a work piece, og, Tor high quality or accuracy, and relatively high where large vohunes of material may be expelled, e.g. for reason that guahty may locally not he of concern or be guaranteed alse 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, # may also be the case that a receiving chamber or secelving chamber part is provided with & pressure sensor, A major advantabe of having such pressure sensor is not only tu controlling delivery of a constant stream of material and at certain pressure, but also the possibility to thmely control towards a sealed

1S retraction action of the filament, in which, af 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 fumes. [00371 1 hence goes without saying that the 3D printer according te the present vention is provided with a controller controlling pressure and temperature in conjunction, Le, as a function of the local nature of the work piece te be printed, and that different parts of 8 work piece may be printed with different speed, volume of flow and/or temperature of delivery,

9.

[0038] Clauses

1. Method for application to a 3D printer, in which the heater block is included in the print head in a marmer surrounded by a standing volume of air.

2 3D Printer, in particular according to the preceding claim, 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.

3. Printer according to any of the preceding clanns in which the heat sink is produced in an aluminum material.

4, Printer according to any of the preceding claims, in which the heater block is produced in aluminum.

5. Printer according to the preceding claim, 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 costing.

Is 6, Printer according to any of the preceding claims, in which the heater block is provided in a two part form comprising of a cirenmferential outer block part provided with receptacles for electric heater elements, and a central inner part provided with said first and second section receiving chambers.

7. Printer according to the preceding claim, in which the central portion is screwed into the outer portion, the portions thereto being provided with inner and outer screw thread respectively.

8, 3D printer, in accordance with any of the preceding claims, in particular fora 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 printer comprising driving the filament into a heater block, receiving and heating the filament in a first receiving section of the heater block, 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, 6 Printer in accordance with the preceding claim, in which the inner wall of the first receiving section is provided with grooves spiraling towards the lower end of the section,

TÔ

16. Printer In accordance with the preceding claim, in which the grooves each spiral towards an opening In the second receiving section for realiving said separate streams,

11. Printer in accordance with any of the preceding clabros 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.

12. Printer in accordance with the preceding claim, in which the nozzle is provided for adhering to the heater block via screw thread provided to the outer side, 1e, circunference of an end part of the heater block, io 13 Printer In accordance with the preceding claim, in which tightening of the nozzle to the heater block cases an end face of the heater block to inthmately comeet an at least largely corresponding, opposing face provided within the nozzle.

14, Printer in accordance with any of the preceding claims, in which the hester block is thermally sopamied fom a feeder element by means of s connection between feeder £5 clement and beating block centrally comprising a thermally isolating separator or distance member through which the lament is fed.

Printer in accordance with any of the preceding claims, in which the thermally separated connection between feeder clement and heating block comprises radially outward disposed screws, firmly connecting the feeder element to the heater block, 16 Printer according te the preceding claim, in which three, regudarly distributed screws are disposed for said firm connection, preferably the screws incorporated in a fango-like part for the feeder element.

17. Printer according to any of the preceding claims in which an upper wall part of the heat sink forms a flange part to the feeding clement.

18. Printer according to any of the preceding claims in which the feeder clement is centrally screwed into an opper or lower wall part of the circienferential heat sink.

9. Primer according te the preceding claim in which the feeder clement is formed by a mainly tubular or prismatic part, abutting to the thermally isolating distance member by a distal end face.

26 Printer according to any of the preceding claims, 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 te which the feeder clement is secured, e.g. by the part being screwed into the flange Uke part via an immer screw thread thereof,

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21. Method of controlling a 3D printer, in particular in accordance with anyone of the preceding claims, in which the heater block is provided with at least one heat sensor.

22. Method in accordance with anyone of the preceding claims, 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 claims 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 clements as specified in anyone of the preceding claims.

2s. Printer according to the preceding invention provided with a controller controlling pressure and temperature in conjunction, Le. as a function of the local nature of the work piece to be printed.

26. Printer according to any of the preceding printer claims, in which different parts of a work piece may be printed with different speed, volgme of flow and/or temperature 1§ of delivery,

Claims

“12. Conclusions i. Method for application in a private 3D printer, where the heating chamber thereof is incorporated in the print head in a manner wherein it is surrounded by a volume of stagnant 3D Printer, in particular according to the preceding claim, wherein the amount of standing air around the heating block is provided by means of a heat sink which is accommodated in the print head around the heating block.

A printer according to the preceding claim, wherein the throat body is made of a aluminum material. Printer according to any one of the preceding claims, wherein the heating body is made of aluminium.

3. Printer according to the preceding claim, wherein the at least part of the inner wall of one of the core parts is provided with a diamond coating, in particular a nano-dinmant long. fs. Printer according to any one of the preceding claims, wherein the heating sheet is formed in a two-part form consisting of a surrounding outer block part provided with holders for electric heating elements and a contrast inner part provided with the first and second sections of opusem channels. A printer according to the preceding claim, wherein the central portion is screwed into the outer portion, the parts being provided for this purpose with inner and outer screw threads, respectively.

A 3D printer according to any one of the preceding claims, in particular for operating a 2D printer of a con-based production system, wherein a filament printing material is driven into a printer head to be expanded therefrom in molten form, wherein the filament and Blament material is collected and heated in a first receiving part or section, received as a common chamber for receiving filament and filament material, and then divided into separate streams of material in a second, further Blame receiving part or section of the heating block. A printer according to any one of the preceding claims, wherein the inner wall of the first receiving site is provided with grooves spiraling towards the lower end of the section.

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A printer according to the preceding claim, wherein the grooves each extend to an opening in the second receiving portion for realizing said separate flows. tsp. Printer according to any one of the preceding claims, wherein in a further step the heated material is expelled from the heating block via a printer nozzle which receives and substantially partially merges said separate streams, the nozzle being held in intimate thermal contact with the heating block.

A printer according to the preceding claim, wherein the nozzle is configured for bonding to the heating block via screw threads provided on the outside, i.e. the periphery of an end portion of the heating block.

A printer according to the preceding claim, wherein turning the nozzle against the heating block causes an end face of the heating block to come into intimate contact with an at least substantially corresponding opposing surface in the nozzle. the method comprises the steps of driving the filament into a heating block thermally separated from a feed element via a connection between supply element and heating block which centrally comprises a thermally insulating separator or spacer through which the filament is fed, 1S. Printer according to any one of the preceding claims, wherein the thermally separated connection between supply element and heating block comprises radially outwardly positioned screws which firmly connect the supply element to the heating block.

A printer according to the preceding claim, wherein three regularly spaced screws are arranged for said connection, preferably 253 received in a flange-shaped part of the feed element.

A printer according to any one of the preceding claims, wherein an upper wall portion of the cooling body forms a flange portion for the supply element.

A printer according to any one of the preceding claims, wherein the supply element is screwed centrally into the upper wall portion of the surrounding heat sink. end face abuts the thermally insulating spacer.

“14

A printer according to any one of the preceding claims, wherein the supply element is further secured in the print head via a counteracting nut, screwed to the butt side of the tubular part, and abuts against the Hens part to which the supply element is secured, e.g. through the part in the Hens. I screws, through an internal thread thereof,

A method according to any one of the preceding claims, wherein the heating chamber is provided with at least one heat sensor.

A method according to any one of the preceding claims, wherein the 2D principle system is provided with a pressure sensor for directly or indirectly detecting supply pressure ID of the fidement,

A method according to any one of the preceding claims, wherein the receiving chamber or part thereof is provided with a pressure sensor,

24. Printhead specified with one or more of the method steps and printhead elements as specified in the preceding claims.

A printer according to the preceding claim comprising a regulator for controlling the pressure and pressure in conjunction with, ie depending on the local nature of the printing workstick,

A printer according to any one of the preceding claims, wherein different parts of a workpiece can be printed at different speeds, flow rate and/or delivery time.