Anti-tilting device for material powder bottles

Abstract

The invention relates to an anti-tilting device (1) for a machine for producing moulded articles by building up layers of material powder, which device comprises a hold-down device (11) for holding a material powder bottle (2) coupled to a filling interface (3) of the machine and a device coupled to the hold-down device (11) for generating a holding force. In a first state, the hold-down device (11) is arranged at a first position (Z1) to enable coupling or decoupling of a material powder bottle (2) to or from the filling interface (3). In a second state, the hold-down device (2) is arranged at a second position (Z2) in order to transfer the holding force to a material powder bottle (2) coupled to the filling interface (3).

Description

[0001] Tilt protection for material powder bottles

[0002] The present invention relates to an anti-tip device for a machine for producing molded bodies by layering material powder. In particular, the aim is to prevent a material powder bottle from tipping over or falling when filling a material powder container of the machine.

[0003] Selective laser melting (SLM) machines produce components (molded bodies) layer by layer from material powder. The material powder is applied, for example, in a thin layer on a base plate and then completely melted locally using laser radiation. Upon solidification, a solid layer of material forms. The base plate is then lowered by the amount of one layer's thickness, and another layer of powder is applied. This process is repeated until the component is completely built up layer by layer. The finished component is then cleaned of excess powder and further processed as required.

[0004] There are also laser processing machines for additive manufacturing with a powder nozzle, which delivers the powder material to the processing location, where it is melted in the focus of a laser beam to additively produce a molded body.

[0005] A generic device for producing shaped bodies by layering them from powdered material is disclosed, for example, in European Patent No. EP 2 052 845 B1.

[0006] The present application relates to an anti-tip device for machines in which a shaped body is additively built up by melting a material powder, in particular by means of laser radiation. The material powder can in particular be a metal powder or a plastic powder. The term additive manufacturing machine is used below to summarize such machines. The material powder used in an additive manufacturing machine is generally stored in a material powder tank, which must be refilled when the material powder is used up. The material powder tank is filled, for example, via a filling opening or a filling interface. A powder container or a material powder bottle can be placed on such a filling interface for filling. A typical powder container can have a mass of up to approximately 25 kg when fully filled.Furthermore, it is not uncommon for the filling interface to be located at a height of approximately 2 m, which means that the filling process can pose a risk of injury to the worker entrusted with it.

[0007] The term "material powder bottle" is used in this application for the sake of simplicity of description and is not intended to limit the shape of the powder container to that of a bottle. The term "material powder bottle" also encompasses other forms of powder containers or powder containers that are not bottle-shaped, such as wide-mouth drums or the like.

[0008] In the present application, “worker” refers in particular to a person who brings the powder container into interaction with the filling interface for filling the main tank.

[0009] In particular, there is a risk of the powder container tipping over and / or falling during filling, which could injure the worker. Therefore, there is a need to prevent the container from tipping over and / or falling to reduce the risk of injury to the worker.

[0010] The problems known in the prior art are to be remedied according to the invention by an anti-tip device according to claim 1. Preferred embodiments of the present invention are the subject of the dependent claims, the attached drawings and the following description of exemplary embodiments.

[0011] The anti-tip device includes a hold-down device for holding a powder container coupled to a filling interface of the machine. The "coupled" state can refer to a state in which the powder container is only placed or attached to a filling interface but not yet firmly connected. By holding the powder container in place, the hold-down device can prevent the powder container from tipping over or falling before the powder container is firmly screwed in place. This can reduce the risk of injury to a worker. Furthermore, the worker has both hands free to safely connect the powder container to the filling interface.

[0012] The hold-down device is coupled to a device for generating a holding force. This holding force serves to hold the powder bottle in place. This holding force can be generated, in particular, by a spring or a weight.

[0013] The hold-down device is arranged in a first position in a first state to enable coupling or decoupling of a material powder bottle to or from the filling interface. In other words, the hold-down device can be moved to the first position, for example, by moving the hold-down device and / or rotating the hold-down device. When the hold-down device is in the first position, the material powder bottle can be inserted or removed without being hindered by the hold-down device. In other words, the distance of the hold-down device in the first position from the filling interface is preferably greater than a maximum length of a material powder bottle.

[0014] According to a preferred embodiment, the hold-down device can be fixed in the first position. For this purpose, a locking mechanism or the like can be provided, which can be released, for example, by a lever. The locking mechanism can, for example, be part of a kinematic system described below.

[0015] In a second state, the hold-down device is arranged in a second position. In this position, the hold-down device contacts a powder bottle coupled to the filling interface in order to transfer the generated holding force to the powder bottle.

[0016] The device for generating the holding force can have kinematics that can guide a movement of the hold-down device. The movement can include a rotational and / or translational movement. For example, the kinematics guide a linear displacement of the hold-down device along an axis or a rotation about the axis.

[0017] The device for generating the holding force generates the holding force that prevents the powder container from tipping over or falling when not connected to the filling interface. The holding force can be generated, for example, by a spring that is stretched or compressed according to the linear displacement of the hold-down device, generating a counterforce proportional to the linear displacement. The counterforce counteracts the linear displacement of the hold-down device starting from an initial position (first position).

[0018] Instead of a spring, alternative designs can use a weight that generates a holding force through a corresponding weight force. The advantage of this is that the weight force is always the same regardless of the position of the hold-down device.

[0019] If no powder feed bottle is coupled to the filling interface, the hold-down device can be in the first position. This first position can also be referred to as the home position. Preferably, the hold-down device can only be moved from the home position in one direction, for example, parallel to gravity.

[0020] According to a preferred embodiment, the hold-down device can be moved in a range between the first position and a maximum deflection referred to as the third position.

[0021] When using a spring, the spring force in the third position may be zero according to the preferred embodiment or the spring force is preferably very small.

[0022] From the third position, the hold-down device can preferably be moved against a component of the holding force parallel to gravity. The direction of the movement is defined here as a positive direction. This positive direction can be referred to, for example, as the positive Z-direction. The direction of the holding force acts accordingly in a negative direction. In preferred embodiments, the direction of the holding force is parallel to the weight force.

[0023] When picking up a powder bottle, the hold-down device is preferably moved in a positive direction along the axis against the holding force. The maximum deflection achieved when inserting the powder bottle can correspond to the first position. This maximum deflection can depend on the geometry of the powder bottle, e.g., its length.

[0024] When using a spring, it is preferably a compression spring. This has the advantage that the maximum deflection when moving the kinematics can be limited by the spring without the risk of damaging the spring due to excessive tension.

[0025] After coupling the powder flask to the filling interface, the hold-down device can be moved from the first position, for example, in the negative Z direction along the axis, to a second position. In this second position, the hold-down device exerts the holding force generated by the device generating the holding force (e.g., a spring or a weight) on the powder flask, thus preventing the powder flask from tipping or falling.

[0026] According to a preferred embodiment, the hold-down device comprises a receptacle for the powder container, which, thanks to its geometry, can hold a variety of different powder containers with different geometries and prevent them from tipping over. For this purpose, the geometry is designed, for example, to taper in a positive direction from its lower opening, so that powder containers with different diameters can be held by bringing them into contact with the hold-down device at a point in the taper, depending on their dimensions. Hollow cones or hollow pyramids, for example, are recommended as geometries, which can preferably be rotationally symmetrical.

[0027] According to a preferred embodiment, the receptacle can have the shape of a hollow cone. Such a shape can advantageously adapt to material powder bottles with different diameters.

[0028] The kinematics can preferably include a stop that can limit the movement or rotation of the hold-down device. For example, the stop can ensure that the hold-down device can only be moved from the second position toward the second position, i.e., in the negative direction.

[0029] Additionally or alternatively, the stop can be designed in such a way that it limits the displacement of the hold-down device in such a way that a minimum distance between the hold-down device and the filling interface can be ensured, which on the one hand can prevent a collision between the filling interface and the hold-down device and on the other hand can facilitate the insertion of the material powder bottle.

[0030] The kinematics can preferably have one or more bearings to guide the axis. The axis can be designed, for example, as a rod or rail. The bearings preferably determine the direction of displacement and can prevent tilting when the kinematics is moved.

[0031] According to a preferred embodiment, the bearing is, for example, a plain bearing or a ball bearing. Such bearings can ensure safe and low-friction guidance of the kinematics during displacement.

[0032] A material powder container according to the invention for a machine for producing molded bodies by layering material powder comprises a material powder tank for storing material powder and a filling interface for filling the material powder tank with material powder. According to the invention, the material powder container has an anti-tip device according to one of the aspects described herein.

[0033] The material powder container can be part of a machine for producing molded bodies, for example an SLM machine or other additive manufacturing machine, or can be coupled to such a machine as a standalone module to supply the machine with material powder.

[0034] The filling interface may comprise a pipe section connected to the material powder tank, which serves as a line for filling the material powder tank. The pipe section preferably has a closable valve.

[0035] The filling interface can have a lockable coupling for connecting a powder bottle. A powder bottle can be inserted into the filling interface, and by closing the coupling, a secure connection can be established between the filling interface and the powder bottle. After coupling, for example, the valve on the filling interface and a valve on the powder bottle can be opened to allow the powder to flow from the powder bottle into the powder tank.

[0036] A machine according to the invention for producing shaped bodies by layering material powder has a material powder container as described above.

[0037] BRIEF DESCRIPTION OF THE CHARACTERS

[0038] Further advantageous embodiments are described in more detail below with reference to an embodiment shown in the drawings, to which the invention is not limited, however.

[0039] They show schematically:

[0040] Figure 1 Fig. 1 illustrates an embodiment of an anti-tip device according to the invention.

[0041] Figure 2 Fig. 2 illustrates a state when coupling a material powder bottle.

[0042] Figure 3 Fig. 3 shows a coupled material powder bottle with a small diameter, which is held by the anti-tip device according to the invention.

[0043] Figure 4 shows a coupled large-diameter powder bottle held by the anti-tip device according to the invention. DETAILED DESCRIPTION OF THE INVENTION USING EXEMPLARY EMBODIMENTS

[0044] In the following description of a preferred embodiment of the present invention, like reference numerals designate like or comparable components.

[0045] Fig. 1 shows a schematic representation of an anti-tip device 1 according to an embodiment of the invention. The anti-tip device 1 can, for example, be installed in a material powder cabinet of an additive manufacturing machine to prevent a material powder bottle 2 from tipping over and / or falling.

[0046] The anti-tip device 1 comprises a hold-down device 11 coupled to a device for generating a holding force 12, which has a kinematic system. The kinematic system comprises an axis 14, which is linearly displaceable along a vertical direction in Fig. 1 by means of two bearings 15. The vertical orientation shown in the exemplary embodiment is exemplary and should not be understood as limiting.

[0047] In the illustrated embodiment, the device 12 for generating the holding force comprises a spring 13 which, when deflected, generates a spring force which is referred to as the holding force.

[0048] The axle 14 has an L-shaped arm 16 at an upper end, which supports the hold-down device 11. At a lower end, the axle 14 is coupled to the spring 13, which generates a corresponding counterforce when the axle 14 is moved. Fig. 1 shows the hold-down device 11 in an initial position designated as the third position Z3. In this third position Z3, the arm 16 rests on a stop 17, which prevents further downward movement. Instead of the spring 13 or in addition to the spring 13, a weight can also be used in alternative embodiments to generate the holding force.

[0049] The illustrated hold-down device 11 has the shape of a rotationally symmetrical hollow cone, making it suitable for receiving the bottom of variously sized material powder bottles 2. In other alternative embodiments, the holder of the hold-down device 11 can also have the shape of a hollow pyramid, for example.

[0050] The process of coupling a material powder bottle 2 to a filling interface 3 of a material powder container of an additive manufacturing machine is described below by way of example with reference to Figs. 1 to 3.

[0051] Fig. 1 shows an initial state in which no material powder bottle 2 is yet coupled to the filling interface 3. Here, the hold-down device 11 is located at the third position Z3. The spring 13 is relaxed or slightly preloaded. The L-shaped arm 16 of the kinematics 12 rests on the stop 17. In the illustrated embodiment, the kinematics 12 is additionally pulled downward by gravity.

[0052] The material powder bottle 2 comprises an interface 21 for coupling with the filling interface 3. Furthermore, the material powder bottle 2 has a valve 22 which can be opened by turning in order to allow the material powder to flow out of the material powder bottle 2.

[0053] The filling interface 3 comprises a pipe section 31 connected to the material powder container. A valve 32 is arranged on the pipe section 31, which can be opened and closed by turning. Furthermore, the filling interface 3 has a coupling 33, which serves to connect to the interface 21 of the material powder bottle 2. The coupling 33 can be opened and closed via a screw 34.

[0054] In a first step, the worker manually swings the powder bottle 2 into the anti-tip device 1, as indicated by the arrow in Fig. 1, and brings the bottom of the powder bottle 2 into contact with the hold-down device 11. The upward-facing bottom of the powder bottle 2 presses against the hold-down device 11, thereby displacing the kinematics 12 upward. This displacement compresses the spring 13.

[0055] Fig. 2 shows a state after the first step. The spring 13 is compressed here. The hold-down device 11 is located at a position designated as the first position ZI. The L-shaped arm 16 is at an indeterminate distance from the stop 17. The compressed spring 13 limits the displacement of the kinematics 12. During displacement, the axis 14 of the anti-tip device 1 is guided by two bearings 15, which can be designed, for example, as plain bearings or ball bearings.

[0056] In the next step, the worker aligns the material powder bottle 2 in the state shown in Fig. 2 coaxially with the filling interface 3 so that the interface 21 of the material powder bottle 2 can be inserted into the coupling 33.

[0057] The worker can then couple the material powder bottle 2 to the filling interface 3. To do this, they place the material powder bottle 2 with the interface 22 on the filling interface 3. The kinematics 14 are thereby moved downwards again, whereby the spring 13 relaxes by the distance between ZI and Z2. The hold-down device 11 can preferably remain in continuous contact with the material powder bottle 2 as the material powder bottle 2 approaches the filling interface 3. In the state shown in Fig. 3 (second state), the hold-down device 11 is in a position referred to as the second position Z2, which is located between the first position ZI and the third position Z3 and depends on the size of the material powder bottle 2. The L-shaped arm 16 is not yet resting on the stop 17 here.

[0058] Fig. 3 also shows a Z-axis, which indicates the positive direction of the displacement. The displacement from ZI to Z2 thus occurs in the negative Z-direction. Furthermore, the positions ZI and Z2 are shown for comparison with Z3.

[0059] When lowering from the first position ZI to the second position Z2, the spring 13 is released by the corresponding distance between ZI and Z2. However, in position Z2, the spring 13 continues to generate sufficient holding force to prevent the material powder bottle 2 from tipping over. Once the material powder bottle 2 is inserted into the coupling 33 with the interface 22, the worker can release the material powder bottle 2. The material powder bottle 2 is now held at its base by the anti-tip device 1.

[0060] In this state, the worker has both hands free to tightly screw the coupling 33 using the screw 34. Subsequently, the two valves 22 and 32 on the material powder bottle 2 and on the filling interface 3 can be opened so that the material powder can flow into the material powder container.

[0061] In an alternative embodiment, the hold-down device can be locked in the first position ZI. For this purpose, the kinematics can have a locking mechanism that can be released, for example, by a lever. The process for inserting a material powder bottle 2 is similar to that described above. First, the worker can lock the hold-down device in the first position ZI as the starting position (first state, similar to Fig. 2). They can then couple the material powder bottle 2 to the filling interface 3 without having to actively push the hold-down device 11 upwards.

[0062] Then, it releases the locking mechanism and the hold-down device 2 is moved downwards (in the negative Z direction) by the spring force and / or the weight force to the second position (second state, see Fig. 3), where the holder of the hold-down device 11 comes into contact with the bottom of the material powder bottle 2 and holds it in place due to the holding force generated.

[0063] The embodiment illustrated in the figures can also allow a rotational movement of the hold-down device about the axis 14. For example, it may be advantageous to rotate the hold-down device 11 about the axis 14 in order to couple a large material powder bottle 2 to the filling interface 3.

[0064] Fig. 4 shows a further example of a state corresponding to Fig. 3 with a material powder bottle 2' that has a larger diameter than the material powder bottle 2 from Fig. 3. Due to the hollow conical shape of the receptacle of the hold-down device 11, the larger bottom of the material powder bottle 2' can also be held by the hold-down device 11.

[0065] Furthermore, the powder bottle 2' in Fig. 4 is shorter than the powder bottle 2 in Fig. 3, so that the resulting position Z2' is located below position Z2 and thus closer to position Z3. The kinematics 12 thus allows the anti-tip device 1 to be used with powder bottles of different lengths.

[0066] It should be noted that the figures show the hold-down device 11 in cross-section. The holder of the hold-down device 11 is preferably rotationally symmetrical, so that, in particular, a circular bottle bottom of the material powder bottle 2 can come into contact with the holder of the hold-down device 11 along its edge. Thus, the hold-down device 11 can accommodate and hold material powder bottles 2 of different diameters.

[0067] Thus, a variety of different material powder bottles can be used with the anti-tip device 1. The holder of the hold-down device 11 can accommodate different diameters, and the kinematics 12 can adapt to different lengths.

[0068] The inside of the holder can preferably be coated with rubber or another material to increase the adhesion between the material powder bottle 2 and the holder, so that slipping of the material powder bottle 2 in the holder can be prevented.

[0069] For the sake of clarity, not all reference numerals from Fig. 1 are shown in Figs. 2 to 4.

[0070] The features disclosed in the above description, the claims and the drawings may be important both individually and in any combination for the realization of the invention in its various forms.

Claims

PATENT CLAIMS 1. Tilt protection (1) for a machine for producing molded bodies by layering material powder, comprising: a hold-down device (11) for holding a material powder bottle (2) coupled to a filling interface (3) of the machine; and a device (12) coupled to the hold-down device (11) for generating a holding force, wherein: the hold-down device (11) is arranged in a first state at a first position (ZI) to enable coupling or decoupling of a material powder bottle (2) to or from the filling interface (3); and the hold-down device (2) is arranged in a second state at a second position (Z2) to transmit the holding force to a material powder bottle (2) coupled to the filling interface (3).

2. Anti-tip device (1) according to claim 1, wherein the hold-down device (11) has a receptacle configured to hold material powder bottles (2) of different sizes and / or geometries.

3. Anti-tip device (1) according to claim 2, wherein the receptacle has the shape of a hollow cone, a truncated hollow cone, a hollow pyramid or a truncated hollow pyramid.

4. Anti-tip device (1) according to one of claims 1 to 3, wherein the device (12) for generating the holding force comprises a spring (13).

5. Anti-tip device (1) according to claim 4, wherein the spring (13) is a compression spring.

6. Anti-tip device (1) according to one of claims 1 to 3, wherein the device (12) for generating the holding force comprises a weight.

7. Anti-tip device (1) according to one of claims 1 to 6, wherein the device (12) for generating the holding force has a kinematics which is configured to guide a linear and / or rotational movement of the hold-down device (11) along and / or about an axis (14).

8. Anti-tip device (1) according to claim 7, wherein the kinematics comprises a stop (17) to limit the linear and / or rotational movement of the hold-down device (11).

9. Anti-tip device (1) according to one of claims 7 or 8, wherein the kinematics comprises one or more bearings and / or guides (15) for guiding the axle (14).

10. Anti-tip device (1) according to claim 9, wherein the bearing (15) is a plain bearing or ball bearing.

11. A material powder container for a machine for producing molded bodies by layering material powder, comprising: a material powder tank for storing material powder; a filling interface (3) for filling the material powder tank with material powder; and an anti-tilt device according to one of claims 1 to 10.

12. Material powder container according to claim 11, wherein the filling interface (3) has a pipe section (31) connected to the material powder tank.

13. Material powder container according to claim 12, wherein the pipe section (31) has a closable valve (32).

14. Material powder container according to one of claims 11 to 13, wherein the filling interface (3) has a lockable coupling (33) for coupling a material powder bottle (2).

15. A machine for producing molded bodies by layering material powder, characterized in that the machine has a material powder container according to one of claims 11 to 14.

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