FUSED DEPOSITION MODELING PROCESS AND APPARATUS

Abstract

Method and system of fused deposition modeling an object including the steps of fused deposition modeling the object of a first fusible material; fused deposition modeling at least one heating element from a second fusible material comprising electromagnetic radiation absorptive material; exposing the heating element to electromagnetic radiation; wherein the fused deposition modeling the object and the fused deposition modeling the at least one heating element are performed by alternatively depositing layers of the object and the at least one heating element. Use of electromagnetic radiation absorptive material in fused deposition modeling.

Claims

1. A method of fused deposition modeling an object comprising the steps of: fused deposition modeling the object of a first fusible material; fused deposition modeling at least one heating element from a second fusible material comprising electromagnetic radiation absorptive material; exposing the heating element to electromagnetic radiation; wherein the fused deposition modeling the object and the fused deposition modeling the at least one heating element are performed by depositing layers of the object and the at least one heating element alternatively; the method further comprising removing the heating element.

2. (canceled)

3. The method according to claim 1, wherein the exposing the heating element to electromagnetic radiation comprises irradiating the heating element using infrared radiation, and wherein the electromagnetic radiation absorptive material comprises infrared radiation absorptive material.

4. The method according to claim 1, further comprising gradually reducing a strength of the electromagnetic radiation after completing the steps of the method of claim 1.

5. (canceled)

6. (canceled)

7. The method according to claim 1, further comprising fused deposition modeling the at least one heating element as a heating layer around the fused deposition modeled object.

8. (canceled)

9. (canceled)

10. (canceled)

11. (canceled)

12. The method according to claim 3, wherein the infrared radiation absorptive material comprises a filler having a emissivity of at least 0.8.

13. (canceled)

14. (canceled)

15. The method according to claim 3, further comprising leaving an air gap between the object and the heating layer.

16. The method according to claim 3, further comprising fused deposition modeling an infrared radiation transparent layer between the object and the heating layer.

17. The method according to claim 3, further comprising fused deposition modeling a heat conducting layer between the object and the heating layer.

18. A system for fused deposition modeling, comprising: a deposition modeling printing assembly comprising at least two deposition print heads; positioning means for positioning the deposition modeling printing assembly; at least one electromagnetic radiation source; a power supply for supplying the at least one electromagnetic radiation source; a control unit, wherein the control unit is arranged for controlling the positioning means, the at least two deposition printheads, and the at least one electromagnetic radiation source, for: fused deposition modeling the object from a first material; fused deposition modeling at least one heating element from electromagnetic radiation absorptive material; exposing the heating element to electromagnetic radiation from the electromagnetic radiation source; wherein the fused deposition modeling the object and the fused deposition modeling the at least one heating element are performed by depositing layers of the object and the at least one heating element alternatively; the at least one electromagnetic radiation source comprising an infrared radiation source.

19. (canceled)

20. (canceled)

21. (canceled)

22. (canceled)

23. (canceled)

24. (canceled)

25. The system according to claim 18, wherein at least one infrared radiation source is arranged laterally of the heating element.

26. The system according to claim 25, further comprising an infrared reflector arranged laterally of the heating element.

27. The system according to claim 18, further comprising a heater for heating a bottom part of the object to be fused deposition modeled.

28. The system according to claim 18, further comprising a heat cover connected to the at least two deposition print heads.

29. The system according to claim 28, wherein the heat cover comprises a heater.

30. (canceled)

31. (canceled)

32. (canceled)

33. (canceled)

34. (canceled)

35. (canceled)

36. The system according to claim 18, wherein the control unit is further arranged for controlling the positioning means, the at least two deposition printheads, and the at least one infrared radiation source for fused deposition modeling the at least one heating element as a heating layer around the fused deposition modeled object.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] FIG. 1a shows a cross section of a fused deposition modeled object according to an embodiment according to the invention.

[0052] FIG. 1b shows a cross section of a fused deposition modeled object according to another embodiment according to the invention.

[0053] FIG. 1c shows a cross section of a fused deposition modeled object according to another embodiment according to the invention.

[0054] FIG. 1d shows the fused deposition modeled object of FIG. 1a in a perspective view.

[0055] FIG. 2a shows a fused deposition modeling system according to an embodiment of the invention.

[0056] FIG. 2b shows a fused deposition modeling system according to another embodiment of the invention.

[0057] FIG. 3 shows a side view of the fused deposition modeling system according to another embodiment of the invention.

[0058] FIG. 4 shows a top view of the used deposition modeling system according to the embodiment of the invention shown in FIG. 3.

[0059] FIG. 5 shows a portion of the fused deposition modeling system according to the embodiment of the invention shown in FIG. 3.

[0060] FIG. 6 shows a top view of the fused deposition modeling system according to the embodiment of the invention shown in FIG. 3.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0061] Fused Deposition Modeling Material

[0062] Fused deposition modeling filament for fused deposition modeling or three-dimensional additive printing can be made from fusible materials such as thermoplastic materials including ABS, HIPS, PLA, PVA, TPE, PA, PET, PK. Other fusible materials include for example metal alloys with low melting temperature such as tin, indium or bismuth alloys. In the art fused deposition modeling filaments made from these materials are heated and melted in a deposition modeling print head in a fused deposition modeling printer and extruded and deposited in a deposition modeling printer in layers to form a fused deposition modeled object. In order for fused deposition modeled objects or parts thereof made from these materials to be heated during the fused deposition modeling, heatable material can be arranged within or outside the fused deposition modeled object where heating is required, to prevent tension and/or warping.

[0063] WO2009002528 A1 describes method and material for inductively heating a composition of polymer and an electromagnetically susceptive filler, the filler comprising i.e. electrically conductive and/or ferromagnetic particles. The electromagnetically susceptive particles heat up when exposed to an alternating magnetic field due to hysteresis of ferromagnetic properties of the particles or in case of conductive material, by eddy currents in the material.

[0064] This type of electromagnetically susceptive material is used for induction welding of objects. In induction welding two parts made of this electromagnetically susceptive material are brought into contact with each other and the overlapping part is locally heated under pressure by means of a locally applied alternating high frequency electromagnetic field. The electromagnetically susceptive material melts where the electromagnetic field is applied and locally and bonds the parts together.

[0065] The fusible material can for example be the thermoplastics poly(etheretherketone), polyetherketoneketone, poly(etherim ide), polyphenylene sulfide, poly(sulfone), polyethylene terephthalate, polyester, polyamide, polypropylene, polyurethane, polyphenylene oxide, polycarbonate, polypropylene/polyamide, polypropylene/ethylene vinyl alcohol, polyethylene, polyolefin oligomers, liquid modified polyolefins or combinations thereof. From U.S. Pat. No. 6,048,599, cited in WO 2009002528 A1, electromagnetic susceptive additives, i.e. conductive and ferromagnetic particles known for electromagnetic fusion bonding include NiFe alloys and iron. Also ferromagnetic materials can be considered. Furthermore also fusible metal alloys with low melting temperature can be used such as tin, indium or bismuth alloys, enriched with electromagnetic susceptive additives as described.

[0066] This electromagnetically susceptive material can advantageously be made in for example a filament such that it can be used in known fused deposition modeling printers, i.e. three dimensional printers. The electromagnetically susceptive material can also be supplied for example in the form of rods or grains, depending on the requirements and capabilities of the fused deposition modeling printer used. The electromagnetic susceptive material can be deposited and arranged by fused deposition modeling into objects as required, which are inductively heatable during creation of once created by subjecting the objects to an alternating electromagnetic field.

[0067] Fused Deposition Modeling

[0068] The electromagnetic susceptive material can be used in creating objects from the electromagnetic susceptive material or from a combination of electromagnetic susceptive material and low susceptive fusible material. A fused deposition modeled object from electromagnetic susceptive material alone can be partly or wholly subjected to the alternating electromagnetic field. The alternating electromagnetic field has a certain limited penetration depth into the material, so it is preferred to also use low-susceptive fused deposition printing material and limit the use of the electromagnetic susceptive material. Below examples of objects made of such a combination of materials are described.

[0069] FIG. 1a shows a cross section of a fused deposition modeled object 103 which has been printed using the susceptive deposition modeling print filament. The fused deposition modeled object 103 comprises a body 104 which can be printed using standard fusible fused deposition modeling filament. The fused deposition modeled object can be covered with a conformal heating layer 105 of electromagnetic susceptive deposition material. The conformal heating layer 105 can be printed using a fusion deposition modeling print head of the deposition modeling printer. The conformal heating layer 105 can cover the fused deposition modeled object 103 partly such that only thermally sensitive parts of the object body 104 are covered or can cover all of the object body 104.

[0070] The conformal heating layer 105 of susceptive filament material can be printed adjacent to the fused deposition modeled object body 104 without contacting the fused deposition modeled object body material. After completing fused deposition modeling of the fused deposition modeled object, the conformal heating layer 105 can be easily removed. Furthermore, the conformal heating layer 105 can be additionally covered with a thermal insulation layer for preventing thermal losses during the fused deposition modeling and heating of the fused deposition modeled object 103. The conformal heating layer 105 and thermal insulation layer thus form a mantle around the fused deposition modeled object which may also provide structural support to the fused deposition modeled object 103 during the fused deposition modeling of the object 103.

[0071] FIG. 1b shows another example of a cross section of a fused deposition modeled object 103. The susceptive filament material is distributed throughout the fused deposition modeled object body 104, and is made by simultaneously or alternated printing layer by layer with standard fused deposition modeling filament, rods or granulate and susceptive filament rods or granulate material 106, or from susceptive filament material 106 alone.

[0072] When the induction coil 101 is excited, heat is generated inside the fused deposition modeled object causing an increased temperature. In this example, since the susceptive filament material is distributed over the entire fused deposition modeled object body 104, the increased temperature is also available throughout the entire fused deposition modeled object body 104.

[0073] FIG. 1c shows another example of a cross section of a fused deposition modeled object 103. The fused deposition modeled object 103 has pockets 107 of electromagnetic susceptive material printed in the fused deposition modeled object body 104. Thus specific parts of the fused deposition modeled object body 104 can be selectively heated by the induction coil 101 magnetic field.

[0074] The object 103 with the susceptive portions 105, 106 and 107 as described in the examples of FIGS. 1a-1d, can also be subjected by an alternating magnetic field from one or more alternatively positioned induction coils 101, depending on the structure of the fused deposition modeled object 103.

[0075] FIG. 1d shows the fused deposition modeled object of FIG. 1a in a perspective view. It shows that the conformal heating layer 105 of susceptive filament material can also partly cover the fused deposition modeled object body 104.

[0076] FIG. 2a shows an example of a fused deposition modeling system having an xyz-positioning device 201 for three dimensionally positioning a deposition print head assembly 202. The xyz-positioning device can be a three axis system having a horizontal axis (x), a vertical axis (z) and another horizontal axis (y) connected to the z-axis, arranged perpendicular to the x-axis. Many alternatives, such as robotic arms can be used as xyz-positioning device. The deposition print head assembly 202 connected to the xyz-positioning device has two or more deposition print heads 203a, 203b for fused deposition modeling an object 103 positioned on a stage 108. The deposition print heads 203a, 203b are arranged for extruding and depositing fusible filament 205a, and electromagnetically susceptive fusible material 205b on the object 103 to be modeled. The fusible material filament and electromagnetically susceptive fusible material filament 205a, 205b can be wound onto reels 204a, 204b for dispensing the filaments 205a, 205b to the deposition print heads 203a, 203b respectively. It will be recognized by the skilled person that other means and ways for dispensing the (non-susceptive) fusible material and/or electromagnetically susceptive fusible material are available such as for example in the form of grains, sticks or rods which can be fed into the deposition print heads.

[0077] A first deposition print head 203a can for example be used for forming the conformal heating layer 105 of electromagnetically susceptive fusible material as described under FIGS. 1a-1d, while the other print head 203b can be used for forming the actually desired object body 104 from the fusible material. Forming the conformal heating layer 105 and the object body can be performed simultaneously while the deposition print heads 203a, 203b are suitably positioned. Forming the conformal heating layer 105 and the object body 104 can also be performed by alternatively depositing material layers of the respective heating layer 105 and object body 104 while the deposition print heads 203a, 203b are being alternatively suitably positioned.

[0078] After forming the conformal heating layer 105, it can for example be subjected to an alternating magnetic field, generated by an induction coil 101 positioned underneath a stage 108 on which the fused deposition modeled object 103 is placed. The induction coil 101 can be inductively excited by a power supply 102 connected to the induction coil 101. The induction coil 101 can be made from conductive windings which are arranged in for example a flat surface. Such an induction coil can also be referred to as a pancake coil. The conductive windings of the induction coil 101 can also be in an annular fashion below the fused deposition modeled object 103. The induction coil windings can be flat, annularly shaped or any other form is possible, including a rectangular shape or polygon shape.

[0079] FIG. 2b shows schematically an alternative arrangement for the induction coil 101. Various induction coil arrangements are possible depending on position, size, shape and heating requirements of the fused deposition modeled object 103. In FIG. 2b two induction coils 207a, 207b are placed on two opposite sides of an object 103, allowing a more uniform electromagnetic field to be created around the object 103, thereby heating the conformal heating layer 105 of electromagnetically susceptive material more uniformly. In FIG. 2b any fused deposition modeling printer details are not shown.

[0080] Alternatively to inductively heating the heating layer with a high frequency electromagnetic field, the heating layer can be heated using infrared electromagnetic radiation.

[0081] FIG. 3 shows a cross section of a fused deposition modeling system 300, wherein a heating layer 301 is shown, which can be irradiated by one or more infrared radiation sources 304. A fused deposition modeling object 302 is placed within the heating layer 301. The heating layer 301 can be conformal, following the contours of the object 302 as described above, however as shown in FIG. 3, the heating layer 301 can be arranged around the fused deposition modeling object 302 as a mantle without contacting the object 302. The heating layer 301 can cover the fused deposition modeled object 302 partly such that only thermally sensitive parts of the object body 302 are covered.

[0082] For the purpose of heating, the fused deposition modeling system 300 has infrared sources 304 posted laterally from the heating layer 301. The infrared sources 304 can for example be tubular infrared lamps, coiled filament lamps or heaters and the like for irradiating the infrared radiation having wave lengths in a mid-infrared wavelength range of 2 to 30 m. The infrared radiation absorbed by the outer surface of the heating layer 301 heats up this heating layer or mantle 301 to a high temperature. Temperatures exceeding 100 C. or even 200 C. may be achieved for adequately heating and the object 302. The heat accumulated in the heating layer 301 is subsequently passed on to the fused deposition modeling object 302.

[0083] The material of heating layer 301 may contain an infrared absorbent filler such as outlined in Table 1 below:

TABLE-US-00001 TABLE 1 emissivity of infrared absorptive filler materials Filler Filling grade (vol %) Emissivity Carbon black >=40 0.8-0.98 Black soot >=40 0.95 Graphite >=20 0.97 Graphene >=10 0.99 Glass >=30 0.85-0.95

[0084] The filling grade of the filler must be sufficient to obtain an effective emissivity of at least 0.8 and preferably at least 0.9 which is sufficient for use as heating element 301 or mantle.

[0085] As a thermoplastic matrix a material can be used which has its VICAT temperature above 170 C. This allows a structure deposited as heating element to maintain its shape at a workable temperature. Exemplary materials are PET, PA6 and PA66, which are also non-toxic and relatively cheap. Recyclates of these materials are well suited for use in heating elements as described.

[0086] The infrared radiation can be combined with heating the stage 305 of the fused deposition modeling object 302 from below the stage 305 on which the object 302 is positioned using a heater.

[0087] The fused deposition modeling printhead 303 can be equipped with a heat cover 306 attached to the printhead 303. The heat cover 306 is provided with a passage for the printhead 303 and can be adjustable in height relative to the printhead nozzle. As printing progresses, the fused deposition modeling object 302 and heating layer 301 have an increasing height. Since the heat cover 306 is attached to the printhead 303, the heat cover has a fixed distance to the top of the fused deposition modeling object 302 and heating layer 301 respectively. This distance or gap 308 can be chosen in a small distance range d such as 0.1 mm to a few mm. The smaller the gap 308 the better the heat cover 306 prevents air convection from the space 307 between the fused deposition modeling object 302 and heating layer 301, cooling down an inner side of the heating layer 301 and the object 302.

[0088] FIG. 5 shows a portion of the fused deposition modeling system 300 of FIG. 3, wherein the space 307 is filled with an infrared transparent material 501. Sodium or potassium salts such a for example sodium or potassium acetates or chlorides will perform well in fused deposition modeling the salts between the object 302 and the heating element or mantle 301. These salts may be dissolved easily in water after finishing the fused deposition modeling. Moreover, heat conducting materials may also be fused deposition modeled or dispensed within space 307. Example of such materials are mixtures of PEG, PEO, Methyl Cellulose/Alum ide emulsion or silicon oil.

[0089] FIG. 6 shows a top view of the fused deposition modeling system 300 of FIG. 3. In the center the object 302 to be printed and heated is shown. Surrounding the object 302, the heating element or mantle 301 is shown. The heating element 301 has a smooth, curved outer circumference to avoid shading of the IR-radiation from the IR sources 304. The reflectors 308 can be arranged to evenly distribute the IR-radiation beams from the respective IR sources over the heating layer outer surface. Depending on the heating layer shape, the mutual arrangement of the IR-sources 304 and reflectors 308 may be adapted to highlight particular parts of the heating layer 301. The inner circumference of the heating element 301 may have an irregular shape, depending on the outer circumference of the object 302 to be printed. In this particular example a smooth, curved inner circumference would have been adequate for heating the object. As described, the space 307 between the heating element 301 and the object to be printed may be filled up with a infrared transparent or heat conducting material.

[0090] The above embodiments are described by way of example only. Variations thereof are possible without departing from the scope of protection as defined by the claims set out below.

REFERENCE NUMERALS

[0091] 100 fused deposition modeling system [0092] 101 induction heating coil [0093] 102 high frequency power supply [0094] 103 fused deposition modeled object [0095] 104 fused deposition modeled object body [0096] 105 conformal heating layer [0097] 106 electromagnetic susceptive material [0098] 107 susceptive pockets [0099] 108 stage [0100] 200 fused deposition modeling system [0101] 201 xyz-positioning device [0102] 202 print head holder [0103] 203a, 203b print head [0104] 204a, 204b filament reel [0105] 205a, 205b fused deposition modeling filament [0106] 207a, 207b induction heating coil [0107] 300 fused deposition modeling system [0108] 301 heating layer [0109] 302 fused deposition modeled object [0110] 303 fused deposition printhead [0111] 304 infrared radiation source [0112] 305 stage [0113] 306 heat cover [0114] 307 space [0115] 308 reflector [0116] 501 IR transparent or heat conductive layer