Fluid supply system for a 3D printer

Abstract

The present invention relates to a fluid supply system for a 3D printer including a fluid pressure generating device for generating a pressurized fluid flow and with a fluid heating device for heating the fluid flow, wherein the 3D printer has at least one construction chamber which is delimited by a construction chamber with respect to the surroundings of the 3D printer and is sealed in a fluid-tight manner, wherein the fluid pressure generating device, the fluid heating device and the construction chamber housing are in fluid connect ion, whereby the fluid flow can flow through the construction chamber, and wherein the fluid pressure generating device, the fluid heating device and the construction chamber housing define a closed fluid circuit for the fluid flow which is heated by the fluid heating device before entry into the construction chamber.

Claims

1. A fluid supply system for a 3D printer comprising a fluid pressure generating device for generating a pressurized fluid flow and having a fluid heating device for heating the fluid flow, the 3D printer having a construction chamber which is delimited with respect to surroundings of the 3D printer by a construction chamber housing and is sealed in a fluid-tight manner, wherein the fluid pressure generating device, the fluid heating device, and the construction chamber housing are in fluid connection, where the fluid flow is configured to flow through the construction chamber, and wherein a closed fluid circuit for the fluid flow is formed by the fluid pressure generating device, the fluid heating device, and the construction chamber housing, which fluid flow is heated by the fluid heating device before entry into the construction chamber, wherein the fluid supply system comprises a construction chamber entrance area arranged upstream of the construction chamber housing and wherein the construction chamber entrance area comprises a diffuser which is attached to a flow alignment unit.

2. The fluid supply system according to claim 1, wherein the fluid supply system in an operational state is configured such that the fluid flow flows through the construction chamber in the form of a laminar flow.

3. The fluid supply system according to claim 2, wherein the 3D printer comprises at least one print head which is movable within the construction chamber in a multi-axial and/or multi-dimensional manner, and at least one construction platform, which are surrounded by the laminar flow of the fluid flow.

4. The fluid supply system according to claim 1, wherein the flow alignment unit comprises a flow guiding structure for an at least partially laminar alignment of the fluid flow.

5. The fluid supply system according to claim 1, wherein the fluid supply system comprises a fluid sterilization and/or fluid filtering device which is in fluid connection with the fluid pressure generating device, the fluid heating device, and the construction chamber housing.

6. The fluid supply system according to claim 1, wherein the fluid flow has a temperature in a range from about 20° C. to about 400° C.

7. The fluid supply system according to claim 1, wherein the fluid flow has a velocity within the construction chamber in a range from about 0.05 m/s to about 5 m/s.

8. The fluid supply system according to claim 5, wherein the fluid sterilization and/or fluid filtering device, the fluid pressure generating device, the fluid heating device, and/or the construction chamber housing are temperature-resistant up to a maximum temperature of about 300° C.

9. The fluid supply system according to claim 8, wherein the fluid pressure generating device is a flow machine.

10. The fluid supply system according to claim 9, wherein a pressure reducing device is arranged downstream of the flow machine.

11. The fluid supply system according to claim 10, wherein the pressure reducing device, the fluid sterilization and/or filtering device, the fluid heating device, and/or the flow alignment unit are capable of generating at least a pressure reduction of the fluid flow of at least 50 Pa.

12. The fluid supply system according to claim 11, wherein the fluid supply system comprises a particle measuring device which is provided for monitoring operation of the 3D printer and arranged in the construction chamber entrance area between the flow alignment unit and at least one entry opening of the construction chamber housing.

13. The fluid supply system according to claim 1, wherein the fluid flow contains a fluid which is a gas.

14. The fluid supply system according to claim 1, wherein the fluid supply system has at least one gas connection by which the fluid supply system is configured to be filled with at least one process gas other than air, with the 3D printer not being in operation during filling.

15. The fluid supply system according to claim 1, wherein the 3D printer is an FFF 3D printer.

16. The fluid supply system according to claim 3, wherein the at least one print head is movable within the construction chamber in a three-dimensional manner.

17. The fluid supply system according to claim 9, wherein the flow machine comprises a turbo compressor or a ventilator.

18. The fluid supply system according to claim 17, wherein the turbo compressor comprises a radial compressor.

19. The fluid supply system according to claim 13, wherein the gas comprises air.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Further details and advantages of the invention are now to be explained in more detail by means of an exemplary embodiment shown in the drawings in which:

(2) FIG. 1 is a schematic representation of an exemplary embodiment of a fluid supply system according to the invention for a 3D printer;

(3) FIG. 2 is a partial sectional view of a construction chamber entrance area of the fluid supply system according to FIG. 1 and a flow guiding body arranged therein;

(4) FIG. 3 is a schematic, perspective representation of a receiving frame for the 3D printer and for the fluid supply system according to FIG. 1; and

(5) FIG. 4 is a schematic front view of the construction chamber of the 3D printer according to FIG. 1.

DETAILED DESCRIPTION

(6) FIG. 1 shows a schematic representation of an exemplary embodiment of a fluid supply system 10 according to the invention for a 3D printer 12.

(7) By way of example, a 3D printer 12 comprising a Delta kinematic system or also a Cartesian system can be used as 3D printer 12. In principle, the 3D printer 12 can also be a multidimensional printer and/or a printer with a multi-axis printing system.

(8) The 3D printer 12 is designed as an FFF 3D printer (FFF: Fused Filament Fabrication).

(9) The fluid supply system 10 includes a fluid pressure generating device 14 for generating a pressurized fluid flow 16.

(10) The fluid flow 16 contains a fluid which is a gas.

(11) The gas can be either air or a process gas such as an inert gas.

(12) Furthermore, the fluid supply system 10 comprises a fluid heating device 18 for heating the fluid flow 16.

(13) The 3D printer 12 also has a construction chamber 20 which is limited and sealed from the environment of the 3D printer 12 in a fluid-tight manner by a construction chamber housing 22.

(14) In addition, the fluid pressure generating device 14, the fluid heating device 18 and the construction chamber housing 22 are in fluid communication.

(15) Thus, the fluid flow 16 can flow through the construction chamber 20.

(16) Inside the construction chamber 20, the fluid flow 16 has a mean velocity in a range from about 0.2 m/s to about 3 m/s.

(17) The fluid flow 16 can also have a mean velocity inside the construction chamber 20 in a range from about 0.05 m/s to about 5 m/s.

(18) In addition, it is conceivable that the fluid flow 16 can have a mean velocity inside the construction chamber 20 in a range from about 0.1 m/s to about 5 m/s.

(19) Moreover, the fluid pressure generating device 14, the fluid heating device 18 and the construction chamber housing 22 form a closed fluid circuit 24 for the fluid flow 16.

(20) In particular, the fluid flow 16 has a temperature in a range from about 50° C. to about 300° C.

(21) However, it is also conceivable that the fluid flow 16 can have a temperature in a range from about 20° C. to about 400° C.

(22) It is also conceivable that the fluid flow 16 can have a temperature in a range from about 30° C. to about 350° C.

(23) The fluid flow 16 has these temperature ranges especially inside the construction chamber 20.

(24) The fluid flow 16 is also heated by the fluid heating device 18 before entering the construction chamber 20.

(25) The 3D printer 12 also features a print head 26, which can be moved in multiple axes within the construction chamber 20, and a construction platform 28.

(26) The print head 26 and the construction platform 28 are surrounded by the laminar flow of the fluid flow 16 when the 3D printer 12 is ready for operation.

(27) The fluid supply system 10 also has a construction chamber entrance area 30.

(28) The construction chamber entrance area 30 is located upstream of the construction chamber housing 22.

(29) A flow alignment unit 32 is located inside the construction chamber entrance area 30.

(30) The flow alignment unit 32 includes a flow guiding structure 34.

(31) The flow guiding structure is designed as flow guiding body 36.

(32) The fluid supply system 10 according to FIG. 1 also comprises a fluid sterilization and filtering device 38.

(33) The fluid sterilization and filtering device 38 is in fluid connection with the fluid pressure generating device 14, the fluid heating device 18 and the construction chamber housing 22.

(34) In addition, the fluid pressure generating device 14 is a radial compressor 40.

(35) A pressure reducing device 42 is located downstream of the radial compressor 40 (in relation to the direction of fluid flow through the device).

(36) The fluid supply system 10 also has a particle measuring device 44 for monitoring the operation of the 3D printer 12.

(37) The particle measuring device 44 is located in the construction chamber entrance area 30 between the flow alignment unit 32 and an entry opening of the construction chamber housing 22.

(38) In addition, the fluid supply system 10 has a gas connection 46.

(39) The fluid supply system 10 shown in FIG. 1 also includes a pipe system 48 which forms the closed fluid circuit 24.

(40) The pipe system 48 consists of several straight pipe sections and 90° elbows through which the radial compressor 40, the fluid heating device 18, the fluid sterilization and filtering device 38, the construction chamber entrance area 30 and the construction chamber 20 are in fluid communication with each other.

(41) The radial compressor 40 is flanged to the construction chamber housing 22 at a construction chamber outlet, whereas the construction chamber entrance area 30 is flanged to the construction chamber housing 22 at a construction chamber inlet.

(42) Between the radial compressor 40 and the construction chamber entrance area 30, the fluid heating device 18 and the fluid sterilization and filtering device 38 are arranged in the pipe system 48.

(43) The fluid heating device 18 is located downstream of the radial compressor 40.

(44) The fluid sterilization and filtering device 38 is located downstream of the fluid heating device 18 in the pipe system 48.

(45) The fluid heating device 18 is designed as a flow heater which has an electrical heating element that may be in the form of a heating coil, for example.

(46) The fluid sterilization and filtering device 38 may have an EPA, HEPA or ULPA filtering unit, for example.

(47) The fluid sterilization and filtering device 38 may also have a separation efficiency according to the filter classes E10, E11, E12, H13, H14, U15, U16 or U17.

(48) The functioning of the fluid supply system 10 can now be described as follows:

(49) Before starting up the 3D printer 12, the fluid supply system 10 should first check whether the gas suitable for the printing process and the printing material is contained in the construction chamber 20.

(50) This check can be done, for example, with a gas sensor which is positioned inside the pipe system 48 or in the construction chamber 20 and is able to determine the appropriate gas.

(51) The determination of different gases may also require the use of several gas sensors.

(52) The filling of the fluid supply system 10 with air as process gas (after the previously used gas has been evacuated) can be done for example via a supply and discharge valve located inside the pipe system 48.

(53) The radial compressor 40 can be used to support or accelerate the filling process with air.

(54) The 3D printer 12 is not in operation during filling.

(55) After filling of the fluid supply system 10, the fluid supply system 10 is hermetically sealed from the ambient atmosphere by closing the supply and discharge valve (not shown in FIG. 1).

(56) Even before the 3D-printer 12 is in operation, the air inside the fluid supply system 10 can be circulated by means of the radial compressor 40, thus achieving a pre-cleaning of the air.

(57) During this pre-cleaning process, the fluid heating device 18 can already be in operation, which additionally preheats the construction chamber 20.

(58) As soon as the construction chamber 20 has a construction chamber temperature adapted to the material and the component to be produced, the 3D printer 12 starts operating.

(59) During operation of the 3D printer 12, the air leaving the construction chamber 20 is sucked in by the radial compressor 40, is compressed and then fed to the fluid heating device 18.

(60) There, the air is heated to an adjustable or controllable temperature value and, after flowing out of the fluid heating device 18, is fed to the fluid sterilization and filtering device 38 where it is cleaned and filtered; subsequently, it flows downstream into the construction chamber entrance area 30.

(61) Specifically, the fluid sterilization and filtering device 38, the fluid pressure generating device 14 in the form of the radial compressor 40, the fluid heating device 18 and the construction chamber housing 22 are temperature-resistant up to a maximum temperature of about 300° C. However, normal applications may also require lower maximum temperatures in the range from 150-200° C.

(62) During the flow through the construction chamber entrance area 30 whose housing is designed as a diffuser and in which the flow guiding body 36 is arranged, there will build up a laminar alignment of the fluid flow 16.

(63) The flow guiding body 36 thus serves at least partially for the laminar alignment of the fluid flow 16.

(64) However, also the diffuser serves for the laminar alignment of the fluid flow 16.

(65) In the state ready for operation, the fluid supply system 10 is therefore designed such that the fluid flow 16 can flow through the construction chamber 20 in the form of a laminar flow.

(66) Within the construction chamber entrance area 30, the particle measuring device 44 can also measure the particle number before the air enters the construction chamber 20 and make it available as a measured variable to an electronic control unit.

(67) The control unit (not shown in FIG. 1) is used to control a drive system (e.g. an electric motor) of the radial compressor 40 and the fluid heating device 18.

(68) The control unit can be integrated into the fluid supply system 10 or arranged on the construction chamber housing 22.

(69) Moreover, the control unit is electrically connected to all sensors located in the fluid supply system 10 and the construction chamber housing 20.

(70) The fluid supply system 10 and the 3D printer 12 can therefore have one or more pressure and temperature sensors.

(71) Between the construction chamber entrance area 30 and the construction chamber housing 22, the pressure reducing device 42 (e.g. in the form of a perforated plate) can be arranged, which at least partially generates the back pressure necessary for the operation of the radial compressor 40.

(72) The back pressure is necessary to prevent the radial compressor 40 from “running up” in unrestrained manner, i.e. to avoid an unrestrained increase in the speed of the radial compressor 40.

(73) In addition to the pressure reducing device 42, other elements can be involved in the pressure reduction function, such as a guiding means (e.g. the flow guiding body 36) and the fluid sterilization and filtering device 38.

(74) Having flowed through the pressure reducing device 42, the fluid or air flow 16 flows into the construction chamber 20.

(75) The pressure reducing device 42, the fluid sterilization and filtering device 38, the fluid heating device 18 and the flow alignment unit 32 can thus generate a pressure reduction of the fluid flow of at least 50 Pa.

(76) The already heated fluid or air flow 16 then flows through the construction chamber 20 in the form of a laminar flow, so that it contributes to the desired heating of the construction chamber 20 and to the production of a component with as little distortion as possible using the 3D printer 12.

(77) In addition, the pressure generated by the fluid flow 16 inside the construction chamber 20 should always be higher than the pressure surrounding the construction chamber 20 in order to avoid additional particle load and germ contamination from the environment or atmosphere.

(78) After flowing through the construction chamber 20, the air flows out of it and is sucked in again by the radial compressor 40, so that the process described above is repeated.

(79) This process is repeated until the printing process is completed or, for example, a malfunction occurs (e.g. a particle concentration which is too high).

(80) The previously described process can also be carried out as described above with any other process gas than air, so that air as a fluid is to be considered as an example only.

(81) If the process described above is to be carried out with a process gas other than air (e.g. an inert gas), the air must be evacuated from the fluid supply system 10 and the construction chamber 20 of the 3D printer.

(82) The fluid supply system 10 can then be filled with a process gas other than air using the gas connection 46.

(83) FIG. 2 shows a partial sectional view of the construction chamber entrance area 30 of the fluid supply system 10 according to FIG. 1 and a flow guiding body 36 arranged therein.

(84) The construction chamber entrance area 30 consists of a diffuser 50 and the flow alignment unit 32 attached to the diffuser 50 and realized in the form of the flow guiding body 36.

(85) The diffuser 50 is designed as a hollow cone whose shell surface is formed in such a way that it widens in a funnel shape toward the construction chamber (e.g. linear).

(86) Two or more flow-optimized fastening struts (not shown in FIG. 2) can be provided to fasten the flow guiding body 36 to the inner wall of the diffuser 50.

(87) The flow guiding body 36 according to FIG. 2 has a drop-shaped design with a half-dome 52 and a body of revolution 54 which is flush with the largest cross-sectional area of the half-dome and tapers towards the construction chamber.

(88) The flow guiding body 54 tapers from the half-dome 52 along the longitudinal axis or rotational axis of the flow guiding body 36 and ends in a tip.

(89) The flow guiding body 36 can be composed of the bodies described above or made in one piece.

(90) The body of revolution 36 and the diffuser 50 are aligned so as to be coaxial.

(91) The tip of the flow guiding body 36 faces the construction chamber 20.

(92) FIG. 3 shows a schematic, perspective view of a receiving frame 56 for the 3D printer 12 and for the fluid supply system 10 according to FIG. 1.

(93) The receiving frame 56 consists of three vertical profile supports 58, which are aligned to each other according to the corners of an equilateral triangle and are braced in a lattice-like manner by additional cross braces. In principle, however, it is not necessary for the ground plan to be triangular. Square, rectangular or other basic shapes or floor plans are also conceivable.

(94) Attached to the receiving frame 56 is the construction chamber housing 22 which has an outer lattice-like frame 60 whose cross-section also has the shape of an equilateral triangle.

(95) When mounted, the frame 60 has an upper and a lower panel, the lower panel being positioned below the upper panel in the direction of gravity so that the upper panel is spaced a certain height from the lower panel.

(96) The upper and lower panels are also both formed as equilateral triangles, thus limiting the construction chamber 20 in addition to the outer frame 60.

(97) The upper panel is also coupled to the construction chamber entrance area 30, whereas the lower panel supports the construction platform and is coupled to a housing of the radial compressor 40.

(98) The three corner areas of the upper and lower panels are each connected by a vertically aligned linear guide 62 (i.e. a total of three linear guides 62), whose length corresponds to the height between the upper and lower panels.

(99) The outer contour of each linear guide 62 also guides a carriage 64 which can slide vertically relative to it.

(100) Each of the three carriages 64 has two ball-and-socket joints, to each of which a rod-shaped arm is hinged with its first end.

(101) The second end of each arm is articulated to the print head 26, which also has two ball joints for each pair of arms for this purpose.

(102) According to FIG. 3, the print head 26 thus has three pairs of ball joints in total, each of which being oriented towards one carriage 64 and to which two pairs of arms are linked in each case, starting from the three carriages 64.

(103) When the print head 26 is assembled, both arms of each pair of arms are aligned to be parallel to each other.

(104) The three-dimensional movement of the print head 26 within the construction chamber 20 thus follows from its kinematic linkage to the three carriages 64 by means of the arm pairs as well as from the respective vertical linear movements of the three carriages 64.

(105) The vertical linear movement of each carriage 64 is achieved by an electric stepper motor 66 attached to the upper panel by means of a support so as to be located above said panel. Instead of an electric stepper motor 66, a servo motor or other drive unit can be used in principle.

(106) Starting from the stepper motor 66, a belt (e.g. a toothed belt) extends along the entire length of the linear guide 62 which is of hollow design.

(107) A magnetic coupling element (e.g. another internally guided carriage) is attached to the belt and transmits the linear movement of the belt by magnetic coupling to the externally guided carriage 64 arranged on the outer contour of the linear guide 62. Alternatively, the carriage can also be directly driven, e.g. by a cable pull system or a screw drive. In this way, the internal carriage and magnetic coupling can be dispensed with.

(108) FIG. 4 shows an even more detailed schematic front view of the construction chamber 20 of the 3D printer 12 according to FIGS. 1 and 3.

LIST OF REFERENCE NUMERALS

(109) 10 fluid supply system 12 FFF 3D printer 14 fluid pressure generating device 16 fluid flow 18 fluid heating device, flow heater 20 construction chamber 22 construction chamber housing 24 fluid circuit 26 print head 28 construction platform 30 construction chamber entrance area 32 flow alignment unit 34 flow guiding structure 36 flow guiding body 38 fluid sterilization and filtering device 40 radial compressor 42 pressure reducing device 44 particle measuring device 46 gas connection 48 pipe system 50 diffuser 52 half-dome 54 body of revolution 56 receiving frame 58 profile supports 60 frame 62 linear guide 64 carriage 66 stepper motor