NL1043470B1 - Method, 3d manufacturing system and print head therfor - Google Patents

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 10 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. 1043470

Description

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

[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 11 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.

iS 100031 The print head of such systems very often is derived from preceding plastic molding technology, be it that the conventional meliing 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 1A of May 2013 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 | 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 313 printers. Another, generic example of a 3D printer system coping with the necessity of melting a filament of material may a amongst others be found in USH233506 relating to a Hauefier assembly for use in additive manufacturing system.

BRIEF SUMMARY OF THE INVENTION 53 [000d] Inthe present invention various essential improvements have been made to the known 3D printer, both in various constituent parts, which, as will become clear may often also be applied independently from one another, as well as te the method of operating such 3D printer, if not to 4 method of 3D printing, all in view of promoting either or both of the speed and the quality of printing, id

BRIEF DESCRIPTION OF THE DRAWINGS 00081 Various aspeets of the invention and an example of part of an embodiment of the invention is Hlustrated in the drawings which depart from the general and wide spread knowledge of 3D printing system and extruders therefor, and in which: IS [Doos] FES. 1 schematically depicts a certain cross sectional view of a print head in accordance with the present invention); {9007} FIG. 2 is another cross sectional view of the same, Ruther clarifying the print head design of the Invention:

[0008] FIG, 3 illustrates from a perspective view the upper end of the beater in accordance with the present invention; 0091 FIG. 4 analogously illustrates the bottom distal end thereof, with a print nozzle tached; [00161 FIG. § schematically illustrates an invention according to which the filament receiving chamber of a heater block splils up to different channels for guiding and heating filament material: ooit} FEE 3A provides an exlernal, perspective view of the preceding; joi] FIG, 6 and GA, in a perspective view illustrate yet an other invention, here cooperating with the invention of FIG. 3, according to which the prini nozzle is screwed to au external thread of the heater block, 00131 FIG, 0A is provides the view with the nozzle removed, and further illustraties a preferred embodiment in which the heater block is split up into four separate channels debouching inte a normally conicaliy shaped plenum of the here not depicted print nozzle;

[00141 FIG. 7 illostrates yet another independently applicable invention and measure, according to which the heater block is split up into an outer section carrying electric heater elements and an inoer, detacheable section in which the receiving sections for the filament to be liquefied: (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; {oois] FIG, 9 and FIG. 9A illustrate the latter design of figure 7 and 8 from different perspective views.

00171 FIG. 10 and 10A from an outer perspective view and from a cross sectional view illustrate 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 figure 1 and 2, FIG. 10A also illustrates the invention of providing a 153 thermaliy isolating distance member between the heat sink, be it the upper wall thereof, or the lower end thereof as in prior art designs.

{6018} FIG. 11 and 11A illustrate the latter design in a perspective view with an without the print nozzle attached, and also showing a measure to have the electric heating elements partially protruding from, i.e, through the outer heat block part; [octet HIG. 12 1Hustrates an embodiment in which the heater block section accommodating the separate channels is designed of greater height that than the first section with central recetving chamber for the filament.

[oo20] FIG. 12A illustrates the invention relating to the thermally decoupling distance member applied in an otherwise largely conventional printer head design; (00211 BRS. 13 illustrates the application of the invention of a standing layer of air, or circunmiferentially applied heat sink to an otherwise largely conventionally designed heater block.

0022} FIG, 13A illustrates the application of circumferentially 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 144A illustrate different perspective views of the design according to FIG, 13.

de [0241 FIG. 15 illustrates a print head carrying system according to another aspect of the present invention according to which the print head is supported by what may be culled a compliant joint, comprising npwardly extending lugs attached Lo the print head, articulating with an intermediary block over a first axis, the intermediary block § articulating with a support rod over a second axis oriented transverse to the first axis, both parallel! to an imaginary of previewed work piece area, the invention taking away lag from the system;

[0025] FHS 16 and 16A illustrate the same from a top and bottom view respectively, and both FIG, 15 and 16, dong with figure 1 illustrating another aspect of the invention, in iG which the print head accommodates cooling or ventilation means, further controlling and improving the process and work piece to be delivered.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 0026; FIG, 1 and further disclose a method of operating a 3D printer of a 3D printing IS based mannfactoring system in which a filament of printing material is driven into a printer head, in which the filament is driven into a printer head se as to be expelled therefrom in molten form, the method comprising the steps of diving the filament into a hester block thermally separated from a Teoder element by means of a connection between feeder element and hexting block centrally comprising a thermally isolating separator or distance member through which the filament is fed, By including a thermally not or mindosally 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, 1e. 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, a2 Yet a further, in fact also independently applicable measure gcoording to the present invention holds the receiving snd heating of the filament in a fist receiving section inchided 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 therdlo, high heating temperatare 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

5.

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 10 the circumferential parts of the filament to be spelled out. {0028} 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 in the second receiving section for realizing said separate streams. [00291 According to yet a farther, and in fact also independently applicable method step, the heated material is and expelled from the heater block via a printer nozzle, receiving iS 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 tl 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 te the outer side, ie. 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 nozele, 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.

Be (00307 Eis 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 ander maintaining the pre-mentioned thermally decoupling 3 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 IO temperature at entry of the filament, at least temperature wise favorable condition, when compared to prior art designs. So as io promote this remoteness of a potential heat bridge, the three screws are regularly distributed disposed for said firm connection, preferably the serews 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 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 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.

29 10030 In yet a further development of the present invention, and also squally 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 it's 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 incladed in the print head circumierentially 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 farther 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.

J [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 pan of the heat sink may torn 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.

[0033] 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 pant and abutting the Range like part to which the feeder clement is secured, e.g. by the part being screwed into the flange like part via an inner screw thread thereof,

[0034] In a further favorable development of the method according to the invention, the heat sink is produced in an alyminam material, keeping centrifugal 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 it's 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.

[00351 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, Le. taken away therefrom e.g. for replacement, the portions thereto being provided with inner and outer screw thread respectively.

8- [00361 In vet 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 ff relatively slow printing speeds are desired for any particular 3 section of a work piece, e.g.

Tor 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

IQ the filament, Where such a sensor could e.g. also be included in the extruder of the filament or to a motor shaft thereof, tt may also be the case that a receiving chamber or receiving chamber part is provided with a pressure sensor.

A major advantahe of having such pressure sensor is not only in controlling delivery of a constant stream of material and at certain pressure, bat alse 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. {9037} Thence goes without saying that the 30 printer according te the present invention is provided with a controller controlling pressure and {temperature in conjunction, Le. 88 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.

A 0038] Clauses

1. Printer in particular for 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, in which, the heated material is and expelled from the heater block via a printer nozzle, 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. Ze Printer according to the preceding claim, the nozzle receiving separate streams of material and recombining the same for at least in part, the nozzle thereby maintained in intimate thermal contact with said heater block.

3. Printer in accordance with the preceding claim, 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. 4 Method for application to a 3D printer, in which the heater block is included in the print head in a manner surrounded by a standing volume of air, 3, 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. 6 Printer according to any of the preceding claims in which the heat sink is produced in an alominom material.

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

8. 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 coating.

9. Printer according to any of the preceding claims, 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,

10. 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.

tL 3D printer, in accordance with any of the receding claims, in particular for a 30 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 ito a heater block, receiving and heating the filament in a first receiving section of the heater block, included as a common chamber for receiving Bament and Blament material, and subsequently dividing the filament material within a second, further filament receiving section of the heater block into separate sireams of material.

12. Printer in accordance with the preceding claim, m which the inner wall of the first receiving section is provided with grooves spiraling towards the lower end of the seetion, 13 Printer mn accordance with the preceding claim, in which the grooves each spiral towards an opening in the second receiving section for realizing said separate streams. 14, Printer In accordance with any of the preceding claims, in which the heater block is thermally sepamied fom 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. iS, Printer in accordance with any of the preceding claims, in which the thermally separated connection between feeder element and heating black comprises mdially outward disposed screws, fivmly connecting the feeder element to the healer block,

6. Printer according to the preceding claim, in which three, regularly distributed screws are disposed Tor said fim connection, weferahly the screws incorporated In a Hange-like part for the feeder element.

17. Printer according to any of the preceding claims in which an upper wall part of 23 the heat sink forms a ange part to the feeding element, 18, Prister according to any of the preceding claims in which the feeder element is centrally screwed into an opper or lower wall part of the cream ferential heat sink.

19. Printer according to the preceding claim in which the fooder element is formed by a mainly tubular or prismatic part, atuitting to the thermally isolating distance member bya distal end face,

28. 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 tc the outer side

11e 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.

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,

25. 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, volume of flow and/or temperature of delivery.

Claims (1)

“12. Conclusions i. Printer, particularly for use in a 3D printing based woductio system, wherein con filament printing material is driven into a printer head to be expanded therefrom in molten form, wherein the heated material is expelled from the heating chamber via the primer nozzle, wherein the nozzle is formed to be connected to the heating block via screw threads provided on the inside, i.e. perimeter of a finder part of the heating block, i.e. 2. Printer according to the preceding claim, wherein the nozzle nozzle receives separate flows and at least partly merges them together wherein the nozzle is maintained in thermal contact with the heating block. 3. 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 superimposed opposing surface in the nozzle 4. Printer according to any one of the preceding claims, wherein The heating block is accommodated in the print head in a manner in which it is surrounded by a volume of standing air. Printer according to any one of the preceding claims, wherein an amount of standing air is provided around the heating chamber by means of a heat sink which is inserted around the print head. heating block is included. &. Printer according to any one of the preceding claims, wherein the heat sink is made of ven ddomininnu material. A printer according to any one of the preceding claims, wherein the heating block is made of aluminium, A printer according to the preceding claim, wherein the at least part of the inner wall of one of the chamber parts is provided with a diamond coating, in particular a nato diamond layer. A printer according to any one of the preceding claims, wherein the heating block is formed in a two-part form comprising a surrounding outer block portion provided with holders for electrical heating elements and a central bioretaining portion provided with the first and second section of meeting chambers. «13- 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, il. Printer for operating a 3D printer according to any one of the preceding claims, in particular for a 3D printer based production system, wherein a filament cover material is driven into a printer head to be expanded therefrom in molten form, wherein the filament and flament material is collected and heated in a first receiving portion or section, received as a common chamber for receiving filament and filament material, and then divided into separate material steams in a second, further filament receiving portion or section of the heating block, A printer according to the preceding claim, wherein the inner wall of the first receiving part is provided with grooves spiraling towards the lower end of the section. A printer according to the preceding claim, wherein the tests each extend to an opening 10 in the second receiving portion for realizing said separate flows. A printer according to the preceding claim, wherein the method comprises the steps of driving the filament in a heating block thermally separated from a supply 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. includes, 1S. Printer according to any of the preceding claims, wherein the thermally separated connection between supply element and heating block comprises radially outwardly placed 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 received in a flange-shaped part of the supply 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 an upper wall portion of the surrounding heat sink. 1d 19. Printer according to the preceding claim, wherein the supply element is formed by an In need of a tube or prismatic part which abuts with a distal end face against the thermally insulating restraining element, A printer according to any one of the preceding claims, wherein the supply element is further secured in the print head via a mating nut, screwed to the outside of the tubular part, and abutting the flange part to which the supply element is secured, e.g. flange to be screwed, through its converse screw thread, A method according to any one of the preceding claims, wherein the heating circuit is provided with at least ECU heat sensor. A method according to any one of the preceding claims, wherein the 2D printing system is provided with a pressure sensor for directly or indirectly sensing the filament torsion dent, A method according to any one of the preceding claims, wherein a receiving IS chamber or target thereof is provided with a printhead sensor, 34. Printhead specified with one or more of the method steps and printhead elements as specified in one of the preceding claims. 25. A printer according to the preceding claim including a controller for tiling the pressure in accordance with, i.e. depending on the local nature of the workpiece to be dented. parts of a workpiece can be printed at different speeds, flow rate and delivery temperature,