Abstract
Component carrier for an additive manufacturing device, wherein the component carrier comprises a construction surface, on which a component to be manufactured is disposed during the operation of the manufacturing device, wherein the component carrier comprises a sealing surface which radially surrounds the construction surface, and method for post-processing a component manufactured according to an additive manufacturing process using such a component carrier.
Claims
1. A transportable assembly unit which is adapted for detachable attachment to a stereolithographic additive manufacturing device, at a location which is outside the resin vat of the stereolithographic additive manufacturing device, the transportable assembly unit comprising: a component carrier which comprises a construction surface on which a component to be manufactured can be disposed during the operation of the stereolithographic manufacturing device, and a sealing surface which radially surrounds the construction surface; and a container which comprises a sealing surface, wherein the component carrier is adapted for placement onto the container as a lid so as to cover and close and seal the container, and wherein the sealing surface of the component carrier together with the sealing surface of the container are further adapted to seal together against an escape of a photoreactive resin, a washing fluid, and UV radiation from the container.
2. The transportable assembly unit according to claim 1, wherein the container comprises one or more mechanical interfaces for connecting to the stereolithographic manufacturing device or a workstation for post processing.
3. The transportable assembly unit according to claim 1, wherein, on a side facing away from the construction surface, the component carrier comprises a mechanical interface adapted for a releasable connection with a transport device of the stereolithographic additive manufacturing device or a workstation for post processing.
4. The transportable assembly unit according to claim 1, wherein the container comprises at least one connection suitable for connection to a supply line and at least one connection suitable for connection to a discharge line for a washing fluid or a drying gas.
5. The transportable assembly unit according to claim 1, wherein the container is UV-opaque.
6. The transportable assembly unit according to claim 1, wherein the container is only partially UV-transparent.
7. The transportable assembly unit according to claim 1, wherein the component carrier is UV-opaque.
8. A manufacturing system comprising: one or more workstations each for washing, drying and/or post curing a component; and the transportable assembly unit according to claim 1.
9. The manufacturing system according to claim 8, further comprising: a transport device, wherein the component carrier can be releasably connected to the transport device.
10. The manufacturing system according to claim 9, wherein the connection of the component carrier with the transport device can be established and released with the aid of a gripper device.
11. The manufacturing system according to claim 9, wherein the transport device comprises a drive for horizontal movement.
12. The manufacturing system according to claim 8, further comprising a resin vat and an exposure device with spatial resolution, wherein the resin vat and the exposure device are outside the location where the transportable assembly unit is adapted for detachable attachment.
13. The manufacturing system according to claim 8, further comprising: additional functional work areas, which are configured for loading the component carrier and the container as well as for dripping off and drying excess solvent.
14. The manufacturing system according to claim 8, wherein the container is a washing tank and comprises a stirrer for moving a solvent filled therein.
15. The manufacturing system according to claim 8, further comprising: at least one workstation for post curing a component, wherein this workstation is configured for performing optical and/or thermal post curing.
16. The manufacturing system according to claim 15, wherein the workstation for post curing comprises a protective gas supply.
17. A method for post-processing a component manufactured according to a stereolithographic additive manufacturing process, wherein, after manufacturing, a component connected to a component carrier is transported into a workspace, wherein the component carrier seals the workspace against resin and solvent and UV radiation.
18. The method according to claim 17, wherein the component is washed in the workspace that is sealed by the component carrier.
19. The method according to claim 18, wherein, for washing the component, a washing fluid is supplied to and removed from the workspace via at least one connection.
20. The method according to claim 18, wherein, for washing the component, a washing fluid is moved with adjustable, changeable directions and speeds relative to the component by moving the washing fluid and/or by moving the component.
21. The method according to claim 18, wherein, after washing, the component is dried in a workspace that is sealed by the component carrier.
22. The method according to claim 21, wherein, to dry the component, an air stream is supplied to and removed from the workspace via at least two connections.
23. The method according to claim 22, wherein the air stream generated for drying the component moved between the incoming and the outgoing connection with negative pressure.
24. The method according to claim 17, wherein the component is post cured in the workspace that is sealed by the component carrier.
25. The method according to claim 24, wherein, for the post curing of the component, the workspace is illuminated through at least one side wall, for example with UV light.
26. The method according to claim 17, wherein, for the post curing of the component, the workspace is illuminated by at least two light sources, for example with light, and/or is equipped with a controllable heater in order to thermally cure components in the workspace, independent of UV light.
27. The method according to claim 17, wherein the method is executed by a computer implemented manufacturing system according to any, one of claims 8 to 16, wherein the component carrier is transported by the transport device.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0048] The invention is explained in more detail in the following on the basis of exemplary embodiments, to which the invention is not limited, however, and with reference to the drawings. Specifically, the drawings show:
[0049] FIG. 1 schematically a manufacturing system having a resin vat and a container sealed by a component carrier in a sealing position;
[0050] FIG. 2 schematically a simple open container;
[0051] FIG. 3 schematically a side view onto an open container according to FIG. 2 with a component carrier disposed above it in an open position;
[0052] FIG. 4 schematically a vertical section of a closed container, which is sealed by a component carrier and is in a sealing position;
[0053] FIG. 5 schematically a manufacturing system having several workstations and having a transport device;
[0054] FIG. 6 schematically a sealed container having media connections;
[0055] FIG. 7 schematically a container according to FIG. 6 docked into a workstation;
[0056] FIG. 3 schematically a post curing chamber with an inserted container;
[0057] FIG. 9 schematically a post curing chamber with an inserted container and having a convection heater;
[0058] FIG. 10 a component carrier on a washing tank having an integrated stirrer and an additional lid; and
[0059] FIG. 11 schematically a washing tank closed with a lid without an inserted component carrier.
DETAILED DESCRIPTION
[0060] FIG. 1 shows an additive manufacturing device 1 having a resin vat 2 and an exposure device with spatial resolution. The manufacturing device 1 would also be usable as a manufacturing station of a manufacturing system. The additive manufacturing device 1 (a “3D printer”) is laser and DLP-based. Liquid photopolymer resins can be processed to solid components in said additive manufacturing device according to the principle of “overhead vat polymerization”. Photopolymerization by means of UV light (ultraviolet light) is used as the solidification principle. The UV light is used to project a mask by means of a UV laser or a DMD-based (“digital micromirror device”) UV projector. The projected mask also marks the area in the resin bath in the resin vat 2 in which the material solidification occurs. A layer thickness, within which the material curing takes place, is assigned to each mask. For the additive manufacturing, the digital volume model of the component to be printed is disassembled into layers. The mask is repeatedly exposed until all the layers of the object to be printed have been exposed. In order to ensure that the individual layers are not all exposed into one another, a component carrier 3 is moved out of the exposure zone away from the base of the tray in z-direction 4 by at least one layer thickness after each layer cycle.
[0061] A container 5, preferably rigid, is attached next to the additive manufacturing device 1. In order to minimize the opportunities for the resin to drip into the machine interior of the manufacturing device 1 as much as possible, said container is positioned as close as possible to the resin-carrying components such as the resin vat 2. The container 5 comprises a mechanical interface 6 for a releasable insertion into the additive manufacturing device 1. After the completion of the additive manufacturing of a component, the component carrier 3 along with the attached, additively manufactured component can be placed onto the container 5 as a lid. The container 5 is then covered and sealed by the removable component carrier 3 of the additive manufacturing device 1. The container 5 and the component carrier 3 thus form a self-contained transportable assembly unit, which can be removed from the manufacturing device 1 without resin contact by the user for transporting to a workstation for post treatment.
[0062] The component carrier 3 comprises a construction surface 7 (see FIG. 4). During the operation of the manufacturing device 1, a component S is manufactured on the construction surface 7, wherein the first manufactured layer of the component 8 is connected to the construction surface 7. The connection of the component carrier 3 to a transport device 9 can be established and released by means of a gripper device. For this purpose, the component carrier 3 comprises a mechanical interface 10. The mechanical interface 10 is formed by a slot 11 for accommodating a coupling element on the transport device 9. The slot 11 comprises undercuts for corresponding projections or extendable clamps of the gripper device or generally for a coupling element on the movable arm 12 of the transport device 9. The coupling element can be inserted horizontally into slot 11 until it hits an end stop. The component carrier 3 can then be lifted off the container 5 along with the transport device 9 and the container 5 can thus be opened.
[0063] In a method for post-processing a component manufactured according to an additive manufacturing process, a component 3 connected to the component carrier 3 via support structures 8′ is accommodated in a workspace 13 in the container 5 after manufacturing and transported in said container, wherein the component carrier 3 seals the workspace 13 against resin and/or solvent and/or uv radiation, and thus largely shields the component 8 from harmful external influences.
[0064] FIGS. 2 to 4 show different component carriers 3 and containers 5 in more detail, whereby, to avoid repetition, the same reference signs have been used for functionally identical parts and the commonalities are described in the following for all the variants. The component carrier 3 comprises a construction surface 7 and a sealing surface 14 which radially surrounds the construction surface 7 (see FIGS. 3 and 4). The component carrier 3 is UV-opaque. The container 5 has a base 15, four side walls 16 and an opening 17 opposite to the base 15. The base 15 and the side walls 16 are UV-opaque. The upper edges of the side walls 16 adjacent to the opening 17 respectively comprise a sealing strip 18, wherein four sealing strips 18 together form a seal 19 in the form of a closed frame, which radially (in relation to a center axis perpendicular to the base 15) surrounds the opening 17. The seal 19 is disposed in a plane parallel to the base 15, so that, in the sealing position shown in FIG. 4, in which the component carrier 3 tightly closes the container 5, the construction surface 7 of the component carrier 3 is disposed parallel to the base 15 of the container 5. The sealing surface 14 of the component carrier 3 is sealed with a corresponding sealing surface of the container 5, more specifically the seal 19 of the container 5, against the escape of a photoreactive resin and/or a washing fluid and/or UV radiation from the container 5. On an upper side 20 facing away from the construction surface 7, the component carrier 3 according to FIG. 4 comprises a mechanical interface 10 for a releasable connection to a transport device 9.
[0065] FIG. 5 shows a manufacturing system 21 with several workstations 22 for washing, drying and post curing a component. The manufacturing system 21 includes a component carrier 3 and a container 5 according to FIG. 4, which is disposed in a work area 23 that can be used for loading the component carrier 3 and the container 5 as well as for dripping off and drying excess solvent, in addition to the work area 23, the manufacturing system 21 comprises several workstations 22. Two workstations 22 each comprise a washing tank 24, 25. A third workstation 22 is a post curing chamber 26 for thermal post curing of a component using a controllable heater. In the course of post-processing, the temperature in the workspace of the post curing chamber 26 is increased to a post curing temperature of preferably 50° C.-90° C., in order to thermally cure the component independent of optionally additionally provided UV light (see FIG. 7). The manufacturing system 21 further includes a transport device 9 and the component carrier 3 is connected to the transport device 9. The transport device 9 comprises a drive for horizontal and vertical movement.
[0066] To use the manufacturing system shown in FIG. 5, the container 5 is inserted into the work area 23. A gripper on the movable arm 12 of the transport device 9 can now be moved by means of the z-tower 27 of the transport device 9 in order to couple to the component carrier 3. In the coupled state, the component carrier 3 can be moved up into a collision-free work area via the z-tower 27 (this position is shown in FIG. 5). The z-tower 27 can be moved in both directions 29 along a horizontal x-axis 23 starting from the work area 23. After reaching the upper position on the z-tower 27, the component carrier 3 can be driven to the individual workstations 22 according to a preselected program. The workstations 22 are formed by the first washing tank 24, the second washing tank 25, the drying area 30 above the washing tanks 24, 25 and the post curing chamber 26. The necessary post-processes are also carried out in the abovementioned sequence. For the first washing process, the component carrier 3 is positioned above the first washing tank 24 and, after automatic opening of a lid of the washing tank 24, is placed onto the first washing tank 24 by being lowered via the z-tower 27. In doing so, an additively manufactured component 31 attached to the component carrier is submerged into the solvent in the first washing tank 24. In doing so, the component carrier 3 closes the first washing tank 24. In both the first washing tank 24 and in the second washing tank 25 there is a mechanical stirrer, which ensures a relative movement between the additively manufactured component 31 attached to the component carrier 3 and the solvent filled therein. The direction of rotation and the rotational speed of the mechanical stirrer can be set in accordance with the process requirements. After the completion of the first washing process, the component carrier 3 is moved on the z-tower 27 back up into the drying area 30. After a defined drip time, the component carrier 3 is moved along the x-axis 28 to the second washing tank 25 and the second washing process is initiated in the same way as the first washing process. Washing, dripping off and drying times can respectively be defined differently, e.g. as a function of the material and/or the geometry of the component. After the second washing process, a drying process follows, in which the solvent is completely removed from the surface of the component carrier 3 and the attached, additively manufactured component 31.
[0067] Only then is the component carrier 3 moved toward and lowered into the post curing chamber 26. In order to avoid oxygen inhibition (i.e. wherein the presence of oxygen prevents curing), the post curing chamber 26 can be flooded with nitrogen. For this purpose, the post curing chamber 26 comprises a corresponding connection. The post curing chamber 26 further comprises lighting means (lamps or LEDs), which emit UV light in the desired wavelength range. The temperature in the post curing chamber 26 can additionally be regulated by means of active or passive heating and cooling. For the post curing process, the post curing chamber 26 is first flooded with nitrogen and set to the desired temperature. The UV emitting lighting means are then switched on for a defined period of time. The post curing in the additively manufactured component 31 attached to the component carrier 3 is now carried out during the time in which they are switched on. The control of the post curing process can take place such that UV radiation and/or heat is applied. After completion of the post curing, the component carrier 3 is moved back to the container 5 and placed upon it. The user can now remove the container 5 with the component carrier 3 placed upon it. The component carrier 3 can now be removed from the container 5. The additively manufactured component 31 attached to the component carrier 3 can now be removed from the component carrier 3 for mechanical finishing.
[0068] According to a further exemplary embodiment, the manufacturing system 21 according to FIG. 5 can additionally include a manufacturing station similar to the manufacturing device 1 having a resin vat 2 and an exposure device with spatial resolution shown in FIG. 1. In this case, the component carrier 3 can be transported directly from the manufacturing station to the first washing station by the transport device 9.
[0069] According to a further exemplary embodiment, the manufacturing system 21 can additionally comprise an outer housing in accordance with FIG. 5. All the devices shown in FIG. 5 can be accommodated in the outer housing. This allows additional external shielding by the outer housing to be achieved, which, for example, at least temporarily counteracts an exchange of air with the surroundings and/or an entry and/or exit of radiation. The outer housing can comprise a door for inserting and removing the container 5 in a closed state. The outer housing can function like an airlock between the interior of the container 5 and the environment.
[0070] FIGS. 6 and 7 show another, alternative exemplary embodiment. The container 32 shown in FIG. 6 comprises four media connections 33. Two connections 34, 35 are respectively provided for a supply line and two connections 36, 37 for a discharge line of a washing fluid 38 or a drying gas 39. This container 32 comprises two vertical side walls 40, 41 (left and right in the drawing), which are UV-transparent. The two other vertical side walls are UV-opaque. This embodiment of the container 32 is initially handled in the additive manufacturing device 1 in exactly the same way as the previously described container 5 without connections. After that, however, the container 32 with connections 33 simultaneously forms the process chamber for the respective post-processes in a single workstation 42 (see FIG. 7). The media, such as a solvent for washing (e.g. IPA/isopropyl alcohol, ethanol, ester-based or surfactant solution), that are used for post-processing, air for drying and nitrogen for post curing can be supplied and removed via the connections 33.
[0071] The manufacturing system 21 according to FIG. 7 comprises a workstation 42 for post-processing, including optical post curing, of a component 8. The workstation 42 for post curing comprises a shielding gas supply 43. The workstation 42 is formed by an additional device 44, which can be used as an accessory to an additive manufacturing device 1. The container 32 is docked into the additional device 44. When docking the container 32, it must be ensured that all connections 33 are connected tightly to the additional device 44. After the sealing docking, the required post-processes can be performed one after the other, in the first step, the component 8 can be washed in the container 32. To do this, the workspace 46 in the container 32 and sealed by the component carrier 45 is flooded in the first step with solvent for washing. A washing fluid 38 is fed into the workspace 46 via a first connection 34 and removed via a second connection 36. The inflow and circulation creates the desired relative movement between the solvent and the additively manufactured component 8 attached to the component carrier 45. The washing time has been determined with the aid of preliminary tests. The solvent itself is stored in a sufficiently dimensioned tank 47 and circulated between the tank 47 and the workspace 46 during the washing process by means of a circulating pump 53. The returning solvent can optionally be filtered at the tank inlet. In order to simplify the subsequent filtering with a particle filter, the dissolved resin residues can be solidified by means of a UV light source 48. After the completion of the washing process, the component 8 is dried in the workspace 46 that is sealed by the component carrier 45. To do this, the container 32 is emptied completely and flushed with air for the subsequent drying process by introducing an air stream into the workspace 46 via a third connection 35 and removing it via a fourth connection 37. The air for drying is let into the container 32 via a pump 49 and the third connection 35 and discharged again via the fourth connection 37 and a switchable outlet valve 50. Air flushing takes place within a defined drying time. The dried component 8 can then be post cured in the workspace 46 sealed by the component carrier 45. After drying, the container 32 can be filled with nitrogen for post curing. To do this, nitrogen is now fed to the pump 49 via a switch valve 51 instead of air. After filling with nitrogen, the two installed UV lighting means 52 are switched on and the workspace 46 is illuminated through two opposing side walls 40, 41 with UV light. An active manipulation of the post curing temperature is possible both via the gas exchange and via the activation period of the UV lighting means 52; the installation of an additional controllable heater can optionally be provided. After the post curing has taken place, the container 32 can be removed from the additional device 44 with the component carrier 45. Finally then, to remove the chemically cleaned and post cured component 8, the component carrier 45 can be removed from the container 32.
[0072] FIG. 8 schematically shows a post curing chamber 54. A container 55 is inserted into the post curing chamber 54. The container 55 and the post curing chamber 54 are sealed by the component carrier 56. The component carrier 56 has a construction surface 7, to which a previously manufactured component 8 is attached. The component carrier 56 has a sealing surface 57. The sealing surface 57 is arranged in the same plane as the construction surface 7 and surrounds the construction surface 7. The sealing surface 57 tightly contacts a corresponding sealing surface 58 of the container 55 formed by a vertical flange at the opening of the container 55, thereby sealing a workspace 46 enclosed by the container 55 and the component carrier 56. The component carrier 56 comprises a mechanical interface 10 arranged on a top side opposite the construction surface 7 and for a releasable connection to a transport device 9.
[0073] The post curing chamber 54 comprises two ultraviolet (UV) lighting means 52 arranged between a housing 59 of the post curing chamber 54 and on two opposing sides of the container 55. The ultraviolet lighting means 52 in this embodiment are flashlights, each providing a power of a hundred watts (2×100 W). The inner side of the housing 59 facing the ultraviolet lighting means 52 comprises mirror surfaces 60 for reflecting ultraviolet light from the ultraviolet lighting means 52 to the receptacle for the container 55. The housing 59 comprises two air inlets 61 on its topside, above the two ultraviolet lighting means 52. On the bottom of the housing 59 there is an air outlet 62 (exhaust). Between the air inlets 61 and the air outlet 62, a cooling fan 63 is arranged inside the housing 59. The cooling fan 63 provides for an airflow through the air inlets 61 into the housing 59 and through the air outlet 62 out of the housing 59. The airflow cools the ultraviolet lighting means 52 as well as the container 55 and the housing 59.
[0074] The container 55 comprises a connection 64 for a supply line 65 of the post curing chamber 54. The supply line 65 is provided to flood the container 55 with nitrogen through the connection 64 when the container 55 is inserted into the post curing chamber 54. The nitrogen supply can be used to remove oxygen from the workspace 46 or to avoid the entry of oxygen from the environment in order not to disturb the post curing process. The connection 64 comprises a sealing ring 66 and optionally a check valve 67.
[0075] When performing post curing of a component 8, the container 55 is sealed with the component carrier 56 and inserted into the post curing chamber 54 and the connection 64 coupled to the supply line 65. The pressure of the nitrogen provided through the supply line 65 is chosen such as to remove oxygen from the workspace 46 by slightly lifting the component carrier 56 off the container 55 and releasing the overpressure between the sealing surfaces 57, 58. After this purging process, the two ultraviolet lighting means 52 are flashed a predefined number of times, thereby illuminating the workspace 46 through two of the sidewalls 40, 41 of the container 55, which sidewalls are uv-transparent. The housing 59 and the component carrier 56 are UV-opaque. During this post curing procedure, the cooling fan 63 provides an airflow through the housing 55.
[0076] FIG. 9 shows an extended embodiment of the container 55 inserted in the post curing chamber 54. For all elements described in connection with FIG. 8 the same reference signs are used in FIG. 9 and it is referred to the above description to avoid repetition. In addition, the container 55 comprises two connections 68, 69 for a convection heater 70. The convection heater 70 is provided to heat the fluid (e.g. mostly nitrogen) enclosed in the workspace 46. By heating said fluid, thermal post curing of the component 8 is performed. The convection heater 70 comprises a pump 71 (or fan) arranged in a fluid circuit 72 connected to the connections 68, 69 of the container 55. The pump 71 circulates the fluid enclosed in the workspace 46 past a heating element 73, e.g. a heater spiral.
[0077] FIG. 10 shows a washing tank 24 according to FIG. 5 in more detail, albeit still schematically. The washing tank 24 is sealed by the component carrier 3. As indicated by arrow 74, the component carrier 3 can be lifted from the washing tank in a vertical direction or descended onto the washing tank 24 in a vertical direction. The component carrier 3 has a construction surface 7, to which the component 8 is attached after manufacturing the same in an additive manufacturing device. The washing tank 24 is filled with a washing fluid 75. For washing the component 8, a circulation of the washing fluid 75 within the washing tank is provided by a mechanical stirrer 76, in this example having rotating blades. When the washing tank 24 is not in use, i.e. there is no component 8 immersed in the washing fluid 75, the washing tank 24 is closed with a lid 77 attached to the washing tank 24 via a hinge 78. Optionally, the hinge 78 can be coupled to a drive to automatically open the lid 77 when a component carrier 3 with a component 8 is approaching the washing tank 24.
[0078] FIG. 11 shows a different embodiment of a washing tank 79, which is shown in a standby configuration, i.e. without an inserted component carrier or component. In this configuration, the lid 80 seals the washing tank 79. The lid 80 comprises a refill opening 81 covered by a screw cap 82. The refill opening 81 is provided for filling washing fluid into the washing tank 79. A mechanical interface 83 for opening the lid 80 is arranged next to the screw cap 82. In one of the vertical walls, a level sensor 84 is provided in the form of a float switch for sensing the level of washing fluid inside that washing tank 79. Based on the output of the level sensor 34, a warning may be issued that there washing tank 79 requires a refill of washing fluid. At the bottom of the washing tank 79 a basket 85 is provided above the mechanical stirrer 86 for protecting the mechanical stirrer 86 from components that may detach from a component carrier arranged on the washing tank 79.
