Device and method for producing three-dimensional models

Abstract

The present invention relates to a device for manufacturing three-dimensional models by means of a 3D printing process, whereby a build platform for application of build material is provided and a support frame is arranged around the build platform, to which said support frame at least one device for dosing the particulate material and one device for bonding the particulate material is attached via the guiding elements and the support frame is moveable in a Z direction, which essentially means perpendicular to the base surface of the build platform. In so doing, the device provides a material feeding device having a particle material container to supply particulate material in batches from the storage area to the dosing apparatus and to do so with the least possible amount of shearing forces and without significant interaction with the atmosphere.

Claims

1. An apparatus for manufacturing three-dimensional models by means of a 3D printing process comprising: a stationary build platform having a base surface for application of a build material including a particulate material and a liquid material; a support frame arranged around the build platform, to which said support frame is attached: i) at least one coater device for dosing the particulate material over the build platform; and ii) a receiving container for receiving the particulate material and for filling the coater device with the particulate material; at least two vertical positioning units for moving the support frame in a vertical direction; and a material feeding device for supplying the particulate material in batches from a material storage device to the receiving container; wherein the coater device is attached to the support frame via guiding elements; the coater device and the receiving container move in the vertical direction with the movement of the support frame; the material feeding device has a fixed feeding location positioned below the stationary material storage device and a discharge location positioned above the receiving container and movable in at least the vertical direction as the support frame moves vertically; wherein the material feeding device includes a lifting device that moves a crucible to a height that adjusts as the support frame moves vertically.

2. The apparatus according to claim 1, wherein a batch contains less of the particulate material than is required for depositing all layers on the build platform.

3. The apparatus according to claim 1, wherein one batch is sufficient to deposit at least one layer of the particulate material to the build platform.

4. The apparatus according to claim 1, wherein the crucible is moveable in the horizontal direction and/or pivotable.

5. The apparatus of claim 1, wherein the lifting device includes a linear actuator.

6. The apparatus of claim 5, wherein the apparatus includes a print head device for printing a liquid material using individually controlled nozzles for bonding the particulate material.

7. The apparatus of claim 6, wherein the receiving container is permanently attached to the support frame so that the receiving container only moves in the vertical direction.

8. The apparatus of claim 7, wherein the apparatus includes a device for mixing the particulate material with a liquid prior to transporting the particulate material from the material storage device to the receiving container.

9. The apparatus of claim 8, wherein the crucible is covered.

10. The apparatus of claim 1, wherein the crucible is covered.

11. The apparatus of claim 9, wherein the print head device moves in a horizontal direction and is attached to the support frame via guiding elements.

12. The apparatus of claim 11, wherein the crucible has one or more support surfaces for supporting the particulate material so that shear between particles of the particulate material is avoided.

13. An apparatus for manufacturing three-dimensional models by means of a 3D printing process comprising: a build platform having a base surface for application of a build material including a particulate material and a liquid material; a support frame arranged around the build platform having guiding elements, to which said support frame is attached: i) at least one coater device for dosing the particulate material onto the build platform; ii) a receiving container for receiving the particulate material and for filling the coater device with the particulate material; and iii) a print head device for printing the liquid material using individually controlled nozzles for bonding the particulate material; at least two vertical positioning units for moving the support frame in a vertical direction perpendicular to the base surface of the build platform; a stationary material storage device for storing the particulate material, and a material feeding device for supplying the particulate material in batches from the material storage device to the receiving container, wherein the material feeding device has a fixed feeding location positioned below the stationary material storage device, and a discharge location positioned above the receiving container and movable in at least the vertical direction as the support frame moves vertically; wherein the coater device and the print head are attached to the support frame via the guiding elements; wherein the coater device, the print head and the receiving container move in the vertical direction with the movement of the support frame; and wherein the material feeding device includes a conveying crucible for moving the particulate material vertically and a lifting device that moves the conveying crucible to a height that adjusts as the support frame moves vertically.

14. The apparatus of claim 13, wherein the lifting device has a linear actuator.

15. The apparatus of claim 14, wherein the apparatus includes a device for mixing the particulate material with a liquid prior to transporting the particulate material from the material storage device to the receiving container.

16. The apparatus of claim 15, wherein the crucible is covered.

17. The apparatus of claim 13, wherein the crucible is covered.

18. The apparatus of claim 13, wherein the apparatus is free of a spiral conveyor and is free of a pneumatic conveyor for transporting the particulate material from the material storage device to the receiving container.

19. The apparatus of claim 16, wherein the conveying crucible is moveable in the horizontal direction.

20. The apparatus of claim 16, wherein the conveying crucible is pivotable.

Description

(1) In the drawing:

(2) FIG. 1 A spatial representation of one preferred embodiment of the present invention;

(3) FIGS. 2 a) to c) A side view of the device during various filling process steps during the build process;

(4) FIGS. 3 a) and b) Filling process steps at various filling heights of the support frame;

(5) FIG. 4 A side-view representation of another device according to the invention with trough conveyor and closeable troughs; and

(6) FIG. 5 A side-view representation of another device according to the invention with trough conveyor and roofed-over conveyor belt.

(7) FIG. 1 shows an isometric view as an application example of a device that can be used to manufacture 3D models. In addition to other features, this displayed preferred device has a support frame (1) that is moveable in the vertical direction and/or in the X direction by means of positioning units (5).

(8) The support frame (1) carries the particle doser or coater (3) and the bonding unit, for example, a print head (4). The coater (3) and print head (4) can be moved over the length of the support frame (1). The space within the support frame (1) is the build space in which the models are built. The coater unit (3) and bonding unit (4) can access the entire build space.

(9) The coater (3) is retained in its park position when the bonding unit (4) is located within a collision-endangering vicinity. When the coater (3) is located in park position, it can be filled with particulate material.

(10) In a preferred embodiment of the invention, the coater (3) only carries enough particulate material for safely applying one layer of the build process. With such an embodiment, the coater (3) is reloaded after every applied layer with the appropriate particle quantity.

(11) When depositing the next layer, the first step involves elevating the support frame (1) by one layer thickness in the vertical direction. When doing so, this also changes the refilling position of the coater (3).

(12) FIG. 1 shows the refilling device for the coater (3) according to one preferred embodiment. As means for supplying, the refilling device has a lifting device (6), a conveying crucible (7) and a receiving container (8) as well as a storage area, respectively, a silo/mixer unit (9).

(13) According to the invention, process-ready material can be dispensed at the outlet of the silo/mixer unit (9). In the preferred embodiment according to the invention shown in FIG. 2a, a vertically moveable lifting unit (6) brings a conveying crucible (7) under the outlet of the silo/mixer unit (9). After the conveying crucible (7) is filled, it is brought to the current height level of the support frame. Then it can be emptied into receiving container (8).

(14) During transport of the particulate material, it continually comes in contact with the atmosphere, that is, with the oxygen of the air. The contact is essentially limited to the surface. If stricter demands need to be met in regards to the particulate material being used, then the conveying crucible (7) can be implemented as a closeable unit. In this context, it is likewise possible to additionally create artificial atmospheres in conveying crucible (7).

(15) The travel time to the vertical height level at the given build heights can be neglected as long as the vapour pressure of the fluid applied over the particulate material is moderate.

(16) Since the transport crucible (7) is small and always filled right away, no changes to the bulk material as a result of bonding/solidifications are anticipated. If bulk materials are used that exhibit such behaviour, then the process can be ideally adjusted to such because the behaviour is always the same due to the constant filling height.

(17) After the material arrives in the receiving container (8), it is distributed over the length of the coater (3). Spiral conveyors can be used here. These are implemented with lengths that are just long enough to enable uniform filling of the entire coater (3) with particulate material. Selection of short spiral conveyors ensures that the particulate material is not negatively affected.

(18) Depending on the build process, it may prove necessary to transport various particulate materials in the coater (3). For such purposes, the conveying crucible (7) can be alternatively provided with different materials from several silos/mixer units (9).

(19) In terms of material transport, it is conceivable that systems with several conveying crucibles could be used, for example, chain trough conveyors or conveyor belts.

(20) According to the preferred embodiment shown in FIGS. 1 and 2, the silo/mixer unit (9) has a low build height and the outlet is located considerably below the uppermost filling position. The conveying crucible is therefore not only vertically moveable, but additionally moveable in a second direction, horizontally.

(21) An arrangement may also be provided that a silo/mixer unit (9) is suspended above the uppermost filling position. If such is done, then an additional movement direction is dispensed with. The conveying crucible (7) then brings the particulate material down to the receiving container (8). As with the previously described arrangement, it is likewise safeguarded against free fall and the atmosphere.

(22) Both preferred embodiments also protect the support frame (1) from jolts due to powder material falling from great heights. It is easy to take support frame (1) design considerations into account since the low fall height remains constant.

(23) Equally preferable are embodiments in which multiple refilling devices are employed. These may prove necessary if material requirements increase.

(24) According to the invention, other transport mechanisms can also be used that enable variable filling heights of the coater, operate batch-wise and thereby only create low free fall heights.

(25) FIG. 3 depicts the filling process at various vertical locations of the support frame. FIG. 2 shows the filling process by itself.

(26) FIG. 4 shows a device according to the invention that utilises a trough chain conveyor as a supply means. In this case, several troughs (10) are attached to a chain (11). They are filled at the silo/mixer unit and then emptied at the coater. Depending on the particulate material, the covers (12) can be used again to protect against vaporisation and/or oxidation. Depending on the process status of the production system, it is possible to have a control unit intermittently switch on the motors (13) of the drive chain.

(27) As shown in FIG. 5, it may be equally preferable to use a conveyor belt (14) as a supply means in terms of material transport. The particulate material is preferably transported close to the enclosing walls/barriers (15) in order to minimize atmospheric contact. Frictional effects are also present here, however, they are low compared to those associated with spiral conveyors. Here it is also possible to have a control unit intermittently switch on the motors (13) of the drive chain, depending on the process status of the production system.

DESIGNATION LIST

(28) 1 Support frame 2 Positioning units in X direction 3 Coater 4 Print head 5 Positioning unit in Z direction 6 Lifting device 7 Conveying crucible 8 Receiving container 9 Silo/mixer unit 10 Troughs 11 Chain 12 Cover 13 Motors 14 Conveyor belt 15 Barriers