NL1043471B1

NL1043471B1 - Method, 3d manufacturing system and print head therfor

Info

Publication number: NL1043471B1
Application number: NL1043471A
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 THERPOR 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 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.

1§ (00037 The print head of such systems very often is derived from preceding plastic melding 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 30 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 77 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 undedying problem of uniformily 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 WOZ016047732, 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 USH233506 relating to a Heuefier assembly for use in additive manufacturing syste.

BRIEY SUMMARY OF THE INVENTION 004] Inthe present invention various sssential 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 to the method of operating such 3D printer, if not to a method of 3D printing, all in view of promoiing ether or both of the speed and the quality of printing,

BRIEF DESCRIPTION QF THE DRAWINGS 000s Various aspects of the invention and an example of part of an embodiment of the invention is tlustrated in the drawings which depart from the general and wide spread knowledge of 3D printing system and extradess therefor, and in which: 13 [0008] FIG. 1 schematically depicts a certain cross soctionnad view of a print head in accordance with the present invention; 00671 PIG. 2 is another cress spetional view of the same, further clarifying the pot head design of the invention; boos] FIG. 3 illustrates from a perspective view the upper end of the heater in accordance with the present invention; oons] FIG. 4 analogously tHustrates the bottoms distal end thereof, with a print nozzle attached; fo FIG. § schematically illustraties an invention according to which the filament receiving chamber of a heater block splits up into different channels for guiding and beating flarcent maternal; 00111 FIG. SA provides an external, perspective view of the preceding; out) FIG. 6 and 8A, in a perspective view Hhustrate vet 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 heater block.

00) FIG. BA is provides the view with the nozzle removed, and further ilustrates a preferred embodiment in which the heater block is split up into four separate channels debouching inie a normally conically shaped plenum of the here not depicted print nozzle;

(0014) FIG. 7 illustrates 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 inner, detacheable section in which the receiving sections for the filament to be higuefied;

[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;

[0016] FIG. 9 and FIG. 9A illustrate the latter design of figure 7 and § from different IO perspective views.

00171 FIG, 10 and 10A from an outer perspective view and from g cross sectional view illustrate the invention of providing a standing layer of air around the heater block, in particular by providing the heat sink circamferential to rather than in line with the heater block. Asin fignre 1 and 2, PIG, 10A also Hlustrates 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,

[0018] FIG. 11 and 11À 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; Joos 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, IZA illostrates the invention relating to the thermally decoupling distance member applied in an otherwise largely conventional printer head design; ory FIG, 13 illastrates the application of the invention of a standing layer of air, or circurnferentially applied heat sink to an otherwise largely conventionally designed heater block.

00221 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 beater block; 00231 FIG. 14 and 14A illustrate different perspective views of the design according to FIG. 13.

{0024} 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 called a compliant joint, comprising upwardly extending lugs attached to the print bead, articnlating with an intermediary block over a first axis, the intermediary block 3 articulating with a support rod over a second axis oriented transverse to the fist axis, both parallel to an imaginary of previewed work piece ares, the invention taking away lag from the system; [00231 FG 16 and 190A Hlustrate the same Jrom a top and bottom view respectively, and both FIG 15 and 16, along with figure 1 illasteating another aspect of the invention, In iQ 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 [0261 FIG. 1 and further disclose a method of operating a 3D printer of a 3D printing iS based manufacturing system 11 which a Blament of printing material is driven into a printer head, in which the Tiament is driven into a printer bead so as to be expelled therefrom tn molten form, the wothod comprising the steps of driving the filament Info a heater block thermally separated from a feeder element by means of a connection between feeder element and beating block centrally comprising a thermally isolating 2} separator or distance member through which the filament is fod. By including a thermally not or mimmally 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, Le. the filament is instantly brought into contact with a heater block part of a maxinmm possible temperature level. Hence this measure increases the meting capacity of the heater block, and therewith improves both quality and speed of the print head, [00271 Yet a further, in fact also independently applicable messare according to the presesyt 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 subseguently dividing the filament material within a second, further filament receiving 33 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 Hlament stage to a gradually melting at least due to increased temperature environment, soflening of the filament, This softened

8.

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 mots 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 cwenmferential 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 {lament may already mechanically be somewhat mixed or split np, 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,

[0029] According to yet a further, and in fact also independently applicable method 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. In this manner il 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 onter side, Le, 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 farther 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, interval transfer of heat is optimized.

[00307 I is remarked that in a further development of the method in accordance with the vention, the thermally separated connection between feeder element and beating block comprises radially outward disposed screws, firmly connecting the feeder element te the heater block, of coarse onder maintaining the pre-mentiovned thermally decoupling 5 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 ab entry of the filament, at least temperature wise favorable condition, when compared Ie 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 pan for the feeder element. A favorable side effect of this design is that simulianeonsly the rigidity or bending stiffness in the connection between feeder slement and heating block is optimized, if not twaproved relative to many prior art designs, The presently discussed feature may hence, whether or not even only for the latter advantage, or in corguuction with or solely for the thermal effect, hence also de applied sither in conjunction with the preceding for further optimization, bat also independently.

omit In yet a further development of the present invention, and also equally independently applicable measure, the heater block is incloded in the print head in a manner surrounded by a standing volume of a, In this manner, despite continuons movement of the print head a continuously stable thermal eovivonment is created for the heater block, increasing its capacity to maintain a high and constant heat level, therowith 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 Testure is realized by having the a volume of standing air surrounding the beater block provided by way of a heat sink included in the print head circumfcrentially to the heater block. Another important effect of having the heat sink circumferential to the heater block rather 33 than preceding i, 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 filayaent at entry thereof tuto the beater block. Also for this reason alone the heat sink may be included circumferentialiy to the hester block,

Te {0032} In a further development of the latter, the suyronnding 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 sink.

§ {0033} Further to the preceding it may be noted that the feeder element is favorably formed by a mainly tobalar 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 clement 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 hike 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 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 fament material becomes soft in a much cartier 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 18 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 bead,

[0035] 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, 1e. taken away therefrom e.g. for replacement, the pattions thereto being provided with inner and outer screw thread respectively.

§~ {0036} Io yet a further development if the method of 31 printing, in accordance with the present invention, the heater block is provided with st 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 induectly sensing feeding pressure of the filament, Where sach 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 oy 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, but also the possibility to timely control towards a so-called iS reteaction action of the filament, in which, at jumps over the work pisce, no material is meanwhile expelled asin prior ant desigos or leaked at such instance, so that with certainty clean work may be delivered at all uimes, {0837} H hence goes without saying that the 3D printer according 0 the present Invention is provided with a controller controlling pressure and temperature in conjunction, 1.2. 88 4 function of the local nature of the work piece to be printed, and that different parts of a wark piece may be printed with different speed, volume of flow and/or temperature of delivery.

KOR Clauses

1. Method of controlling and operating a 3D printer, in particular in accordance with anyone of the following claims, in which the heater block thereof is provided with at least one heat sensor.

2. 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.

3. Method in accordance with any of the preceding claims in which a receiving chamber or receiving chamber part is provided with a pressure sensor.

4, Printer head specified with any one or more of the methods steps and print head elements as specified in anyone of the preceding claims.

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

6. 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.

7. 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, Le. circumference of an end part of the heater block,

8. 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.

9, 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.

10. 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,

~1 il. ID Panter, in particular according to the preceding claim, in which a volume of standing air surrounding the beater block is provided by way of a heat sink included in the puut head circunferentially to the heater block,

12. Printer according to any of the preceding claims in which the heat sink is produced in an alumdmum material.

13. Printer according to any of the preceding claims, in which the hester block is produced in aluminum. id. Printer according to the preceding clan, in which the at least part of the inner wall of anyone of the chamber sections is provided with a diamond, in particular nano- U diamond coating.

15. Printer according to any of the preceding claims, in which the heater blocks provided In a two part form comprising of a circumferential outer block part provided with receptacles for electric beater elements, and a central Inner part provided with said first and second section receiving chambers, 518 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 serew thread respectively.

17, 313 printer, in accordance with any of the preceding claims, in pacticular for a 3D printing based manufacturing system in which a filament of printing material is driven into g printer head, in which the filament is doven into a printer head sp as 10 be expelled therefrom in molten form, the printer comprising driving the filament into s heater block, receiving and heating the filament in a frst receiving section of the heater block, included as a common chamber for receiving filament and filament material, and subsequently dividing the Glament material within a second, further filament receiving section of the heater block into separate streams of material,

18. Printer in accordance with the preceding claim, in which the toner wall of the first receiving sertion ix provided with grooves spiraling towards the lower end of the section, 19, Printer in accordance with the preceding claim, in which the grooves each spiral towards an opening in the second receiving section for realizing said separate streams.

20. Printer in accordance with any of the preceding claims, in which the heater block is thermally separated from a feeder clement by means of a connection between feeder

11e element and heating block centrally comprising a thermally isolating separator or distance member through which the filament is fed.

21. Printer in accordance with any of the preceding claims, in which the thermally separated connection between feeder element and heating block comprises radially outward disposed screws, firmly connecting the feeder clement to the heater block.

22. Printer according to the preceding claim, 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,

23. Printer according to any of the preceding claims in which an upper wall part of the heat sink forms a flange pant to the feeding element, 24, Printer according to any of the preceding claims in which the feeder element is centrally screwed into an upper or lower wall part of the circumferential heat sink, 25, Printer according to the preceding claim in which the feeder element is formed by a mainly tubular or prismatic part, abutting to the thermally isolating distance member iS by g 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 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.

Claims

Sn Conclusions i. Method for activating and operating a 3D printer, in particular according to one of the following printer claims, wherein the confusion block is provided with at least a con-warmle sensor.

Method according to any one of the preceding claims, wherein the pressure system is provided with a pressure sensor for directly or indirectly detecting vessel supply pressure of the filament. A method according to any one of the preceding claims, wherein the receiving IG chamber or part thereof is provided with a pressure sensor,

A printer head as specified in any of the foregoing method claims, and print head elements as specified in any of the preceding claims. A printer as claimed in the preceding claim comprising a controller for controlling the print and temperdow in conjunction with, i.e., independently of the local nature of the workpiece to be printed.

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

7, Printer, In particular for use in a 3D printing based production system, wherein a filament printing material is driven into a printer head to be placed in molten form, wherein the heated material is expelled from the heating body through a printer nozzle, wherein the nozzle is formed to be connected to the heating block via screw threads provided on the outside, i.e. periphery of an end portion of the heating hood.

Printer according to the preceding claim, wherein the prism nozzle receives and at least partially merges separate streams, wherein the nozzle is placed in intimate thermal contact with the heating block. Printer according to the preceding claim, wherein tightening the nozzle against the heating peak causes an end face of the heating block to come into intimate contact with an at least substantially corresponding opposing face in the nozzle

A printer according to any one of the preceding claims, wherein the heating block is received in the print head in a manner surrounded by a volume of standing air, it. Printer according to any one of the preceding claims, wherein an amount of standing air is provided around the heating block by means of a cooling body which is accommodated in the print head around the heating block,

A printer according to any one of the preceding claims, wherein the cooling body is made of an aluminum material.

13. Printer as claimed in any of the foregoing claims, wherein the heating sheet is made of aluminum.

A printer according to the preceding claim, wherein the at least one part of the inner wall of one of the chamber parts is provided with a diamond coating, in particular a nano-diamond layer, 1s. Printer according to any one of the preceding claims, wherein the heating block is formed in a two-part form consisting of an on-lying outer block portion provided with hundreds of electric heating elements and a central inner portion provided with the first and second section of receiving chambers.

16. Printer according to the preceding claim, wherein the central part is screwed into the outer parts, the parts being provided for this purpose with inner and outer screw threads, respectively. 17. Printer for operating a 3D printer according to any one of the preceding claims, in particularly for a 3D printer based production system wherein a filament printing material is forced into a printing head to be expanded therefrom in molten form, the filament and filament material being collected and heated in a first receiving portion or section contained as a common chamber for receiving filament and filament material, and then divided into separate material streams in its second further filament receiving portion or section of the heating block. 1&. Printer according to the preceding claim, wherein the inner wall of the first receiving portion is provided with grooves spiraling towards the lower end of the section.

-14~

A printer according to the preceding claim, wherein the tests each run towards a hole in the second receiving portion to realize several separate streams.

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 feed element through a connection between the feed element and heating block which centrally comprises a thermally insulating separator or fan through which the flame is supplied. overturn.

21. A printer according to any one of the preceding claims, wherein the thermally separated connection between the supply element and the heating block comprises screws positioned vertically on the ball which firmly connect the supply element to the heating block.

22. Printer according to the foregoing claim, wherein three regularly spaced screws are provided for said connection, preferably 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 handle portion for the supply element.

24. Printer as claimed in any of the foregoing claims, wherein the feed element is centrally located in an upper wall. of the surrounding heat sink is screwed. 23. Printer according to the preceding claim, wherein the bell front element is 29) formed by a substantially tubular or prismatic part which bears with its distal end face against the thermally insulating supporting element,

28. 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 outside of the tubular part, and abutting the handle part to which the supply element is secured, e.g. To screw them, through an internal thread thereof,