Device for producing three-dimensional objects by successively solidifying layers of a build-up material, in particular powder form, which can be solidified by means of electromagnetic radiation or particle radiation.

Abstract

Device (1) for producing three-dimensional objects (9) by selective laser melting by successive solidification of layers of a build-up material (7), in particular powdered and solidifiable by means of electromagnetic radiation or particle radiation, at the locations corresponding to the respective cross-section of the object (9), comprising a carrying device (8) for carrying the object (9) with a height-adjustable support arranged in a build chamber (4), an application device (6) for applying the build-up material (7), which is stored in a metering chamber (3), and an irradiation device for irradiating the applied layers of the build-up material (7) at the locations corresponding to the respective cross-section of the object, wherein the application device (6) comprises a blade arrangement guided parallel to the coating plane, consisting of a coating blade holder (11) and a coating blade (12) attached thereto. characterized by the fact that the coating blade holder (11) is guided on both sides by side guides (15) on guide rails (20) in opposing groove-like recesses (16a) of side walls (13) above the build chamber (4) and the application device (6) comprises a set of interchangeable blades of at least two differently designed and separately mountable coating blades (12), wherein one coating blade (12) of the interchangeable blade set is designed as a metal blade and one as a rubber blade, wherein the coating blade holder (11) is driven on both sides and the drive on both sides is via a common motor, which synchronously drives drive elements (16) for driving the side guides (15).

Description

[0001] The invention relates to a device for producing three-dimensional objects by successively solidifying layers of a powdered, solidifiable build-up material according to the preamble of claim 1.

[0002] Such devices are known as selective laser sintering (SLS) or selective laser melting (SLM) machines and are used to manufacture three-dimensional components as prototypes or series parts. The objects to be built are constructed layer by layer; each uppermost layer of a powder-like build material is solidified at the respective cross-section in a build chamber using laser radiation.

[0003] The layer-by-layer feeding of the build material, which is stored in a dosing chamber, is carried out by means of an application device. This device transports the build material from the dosing chamber to the build chamber. The application device comprises a coating blade holder and a coating blade attached to it.

[0004] From DE 10 2006 055 073 A1, a coating blade holder with a main arm and two support arms is known. The coating blade is clamped into the support arms and has two projections for rotationally fixed mounting. The coating blade holder is attached on one side to a drive mechanism via a bracket.

[0005] US 2006 / 0219163A1 describes a holder for coating knives and an adjustment mechanism for stereolithography rapid prototyping systems that allows the holder to be removed and replaced without adjusting the height or tilt settings of the coating knives.

[0006] EP 2 010 370 B1 describes a device for producing a three-dimensional object by solidifying powdered build-up material layer by layer at the points corresponding to the cross-section of the object to be produced in the respective layer by the action of a laser or another energy source. The device comprises a substrate on which the object is built and a recoater for applying a layer of the build-up material to the substrate or to a previously at least partially solidified layer.

[0007] EP 2 386 404 A1 describes a device for producing workpieces by applying electromagnetic or particle radiation to powder layers. The device comprises a process chamber housing and a powder application device arranged in the process chamber housing for applying raw material powder to be exposed to electromagnetic or particle radiation onto a carrier.

[0008] DE 103 60 094 A1 describes a construction device for the layer-by-layer production of molded parts from building material by introducing radiant energy with at least one horizontally movable coating arrangement for transporting the building material from a storage container into the construction space, wherein the building material can be applied as a uniform layer on a construction surface by at least one downward-facing edge of the coating arrangement.

[0009] DE 10 2009 056 689 A1 describes a horizontally movable coater with an elongated metering chute and an elongated feed hopper arranged above the metering chute, wherein the metering chute and / or the feed hopper are pivotably connected to the coater about a pivot axis into a cleaning position in which a discharge opening of the feed hopper and a feed opening of the metering chute are exposed.

[0010] The invention is therefore based on the objective of providing a device of the type mentioned at the outset, comprising the features of the preamble of claim 1, which improves the coating result. This objective is achieved by the characterizing features of claim 1. Advantageous embodiments of the invention are set forth in the dependent claims.

[0011] The core of the invention according to claim 1 is considered to be that the coating blade holder is guided on both sides and comprises a set of at least two differently designed and separately mountable replacement blades with at least one metal and one rubber blade.

[0012] The combination of features of claim 1 ensures, on the one hand, a high-quality coating result, and on the other hand, the coater, thanks to its interchangeable blade set comprising at least one metal blade and one rubber blade, is versatile and suitable for use with different types of powder. Despite the interchangeability of the blades, the combination of double-sided guidance and the interchangeable blade set results in a high degree of reproducibility of the coating outcome. The double-sided guidance allows the use of a solid plate as a blade holder, onto which the blades can be easily attached.

[0013] Advantageously, in addition to the existing at least one coating blade designed as a metal blade, two different rubber blades can be provided, differing in the stiffness of their rubber lip. This increases the versatility of the coating device according to the invention. Advantageously, the coating blade is fixed to the front of the coating blade holder. According to the invention, the coating blade holder is driven from both sides by a common motor. This further improves and standardizes the coating result. Advantageously, toothed belts can be used as drive elements, circulating on both sides of the coating blade holder and coupled to the common drive motor, for example, via a bevel gear.It can also be advantageous to arrange two independently rotating drive elements on each side of the coater blade holder. This allows, in addition to the coater, which is driven by a first pair of drive elements, for example, a grinding roller to be moved across the build surface by a second set of drive elements, independently of the coater. During the coating process, the grinding roller is parked in a first corner of the build chamber, so that the coating process can proceed undisturbed by the grinding roller. If the coater is retracted over the metering chamber area, the grinding roller can then, if necessary, process the surface of a partially built workpiece to be recoated, in particular smooth it.

[0014] The side guides of the coating blade holder are guided in opposing groove-like recesses in the side walls above the build chamber. This allows the drive of the application device to be positioned very close to the build chamber without the build material contaminating the side guides. Due to the close proximity of the side guides to the coating blade holder, no unfavorable lever arm is created; rather, the force transmission can be direct. Furthermore, this design allows for a very compact construction of the application device.

[0015] In a preferred embodiment, the coating blade holder itself is designed as a solid block. This allows for optimized force transmission from the side guides via the coating blade holder to the coating blade.

[0016] Preferably, each side guide consists of a side guide base connected to the lateral end sections of the coating blade holder and ball carriages arranged below it. The ball carriages enable low-friction guidance of the side guides. The ball carriages are guided on rails within the groove-like recesses.

[0017] A particular advantage is that the front surface of the coating blade, which is exposed to the coating material, is flat and free of screw mounting holes. Instead, the coating blade has blind holes on its back side with tapped threads, allowing it to be mounted from the rear. The front surface of the coating blade, responsible for the coating process, is therefore completely smooth. This prevents powder residue from accumulating in screw holes, which could later fall out and impair the coating finish. This further improves the coating process.

[0018] The invention is explained in more detail with reference to exemplary embodiments in the drawing figures.

[0019] These show: Fig. 1 a cross-sectional view of the entire device, Fig. 2. A slanted top view of a building module, Fig. 3. An application device in perspective top view, Fig. 4 an application device with a coating blade in a first embodiment, Fig. 5 an application device with a coating blade in a second embodiment and Fig. 6 an application device with a coating blade in a third embodiment.

[0020] Fig. Figure 1 shows a device 1 for the production of three-dimensional objects by successively solidifying layers of a powdered, solidifiable build-up material. All elements not essential to the invention, such as the irradiation device, which are always required, are not explicitly shown in the drawing. The drawing depicts a build-up module 2 with a metering chamber 3, a build-up chamber 4, and an overflow chamber 5. The application device 6 for transporting the build-up material 7 from the metering chamber 3 to the build-up chamber 4 is movable above the metering chamber 3 and the build-up chamber 4. In the build-up chamber 4, the object 9, which is height-adjustable on a support device 8, is solidified at the corresponding locations by means of laser radiation.Once a layer of build-up material 7 has solidified at the desired locations in build-up chamber 4, the support device 8 is lowered and a new layer of build-up material 7 is transported from metering chamber 3 to build-up chamber 4 using the application device 6. Metering chamber 3 also has a support device 10 for lifting the build-up material 7.

[0021] The application device 6 comprises, among other things, a coating blade holder 11 and a coating blade 12. The application device 6 is guided on both sides in the build module and above the build chamber 4 in groove-like recesses 16a in the walls of the build module 2, as shown in Fig. Figure 2 clearly illustrates this. The walls in which the application device 6 is guided need not be walls of a construction module 2; rather, they can be any walls above the construction chamber 4 or the metering chamber 3. The walls of a construction module 2 can be used, for example, if the construction chamber 4 and the metering chamber 3 are housed within a single construction module 2.

[0022] Fig. Figure 2 shows a partial view of the upper area of ​​the construction module 2. Visible are a side wall 13, a front side wall 14, the application device 6 with coating blade holder 11, coating blade 12, and one of the two side guides 15. The side guides 15 are guided in groove-like recesses 16a of the side walls 13.

[0023] The side guides 15 are driven by means of belts, in particular toothed belts, which are driven synchronously by a common motor.

[0024] Fig. Figure 3 shows a top view of an application device 6. The coating blade holder 11 is designed as a solid block, with the coating blade 12 attached to the front. The screw mounting holes 17 for securing the coating blade 12 are located above the area exposed to the coating material 7.

[0025] The side guides 15 are located on the sides of the coating blade holder 11 and extend beyond the front of both the coating blade holder 11 and the coating blade 12. Because the side guides 15 and the coating blade holder 11 can be connected over a relatively large area, optimized power transmission from the motor via the drive components and then via the side guides 15 to the coating blade holder 11 and thus also to the coating blade 12 can be achieved. The side guides 15 consist of a side guide base 18 and two ball carriages 19. The ball carriages 19 are mounted on the Fig. The rail 20 shown in Figure 1 is guided within the groove-like recess 16a of the side wall 13 of the building module 2. The rail 20 is therefore firmly integrated into the building module 2.

[0026] Out of Fig. Figure 3 further shows that adjusting screws 26 are arranged on both sides of the upper surface 25 of the coating blade. Their inner and lower ends rest on projections of the coating blade holder 11, which extend from the rear into recesses in the coating blade 12. By turning the adjusting screws 26, the coating blade 12 can be finely adjusted. This fine adjustment is made before the fastening screws (26), which pass through the screw mounting holes 17, are tightened. Once an initial coating test shows that the coating result, and in particular the coating thickness, is as desired, the screws (26) can be tightened in the screw mounting holes 17, which are designed as vertically extending elongated holes.

[0027] Instead of two ball carriages 19, in principle more ball carriages or even just a single ball carriage can be arranged below the side guide base 18.

[0028] The side guide bases 18 are each connected to the lateral end sections of the coating blade holder 11 by means of connecting elements.

[0029] As from Fig. As can be seen from Figure 1, the side guides 15 are completely installed in the groove-like recesses 16a of the housing walls. This conceals the space between the rails 20 and the ball carriages 19 from the mounting material 7. The opening in the side wall 13, which allows the connecting elements between the side guide 15 and the coating blade holder 11 to pass through, is covered by the drive elements 16.

[0030] Alternatively to the one in Fig. In the embodiment shown in Figure 3, the coating blade 12 can also be fixed in such a way that no screw mounting holes 17 are required on the front. How Fig. Figure 4 shows that it is possible to provide a kind of projection 21 on the front of the coating blade holder 11, which is provided with through-holes 22. The coating blade 12 has blind holes with pre-drilled threads at the corresponding locations, so that screws for fastening the coating blade 12 can be inserted into the through-holes 22, which may also be threaded. The coating blade 12 is then completely fastened from the rear of the coating blade holder 11, so that no build-up material 7 can become lodged in the through-holes 22 or in the screw mounting holes 17.

[0031] The Fig. 5 and Fig. Figure 6 shows two further possibilities for attaching the coating blade 12 to the coating blade holder 11. Fig. Figure 5 shows a projection 21 on the front of the coating blade holder 11, which is designed as a solid block. The projection 21 has an L-, T-, or cross-shaped recess 23 on its underside, while the coating blade 12 has a corresponding spring 24 on its upper side. Accordingly, the coating blade 12, with the spring 24, can be inserted into the recess 23 of the projection 21 from the side. Since the side walls of the coating blade holder 11 and the coating blade 12 are flush with the side walls 13 of the assembly module 2, the coating blade 12 is fixed laterally.

[0032] Fig.Figure 6 shows a third embodiment for attaching a coating blade 12 to a coating blade holder 11. In this embodiment, the positions of the recess 23 and the spring 24 on the coating blade 12 and the projection 21 are reversed. Thus, in this case, the coating blade 12 has an L-, T-, or cross-shaped recess, while the projection 21 has a correspondingly shaped and associated spring. In this embodiment as well, the coating blade 12 can be slid onto the projection 21 from the side and thus fixed within the module 2.

[0033] The motor for driving the side guides 15 is arranged at a front end of the construction module 2. The drive elements 16, for example toothed belts, are coupled to the motor via a bevel gear and guided in the openings of the side wall 13. REFERENCE MARK LIST 1 Device 2 building modules 3 Dosing chamber 4 Construction Chamber 5 Overflow chamber 6 Application device 7 Assembly material 8 Support device (construction chamber) 9 objects 10 Carrying device (dosing chamber) 11 coating blade holders 12 Coating blade 13 Side wall 14 Front wall 15 side guide 16 Drive element 16a Groove-like recess 17 screw mounting holes 18 Side guide base 19 ball carriages 20 rail 21 lead 22 Drilling 23 Exclusion 24 springs 25 Top of 12 26 adjusting screws

Claims

Device (1) for producing three-dimensional objects (9) by selective laser melting by successive solidification of layers of a build-up material (7), in particular powdered and solidifiable by means of electromagnetic radiation or particle radiation, at the locations corresponding to the respective cross-section of the object (9), comprising a carrying device (8) for carrying the object (9) with a height-adjustable support arranged in a build-up chamber (4), an application device (6) for applying the build-up material (7), which is stored in a metering chamber (3), and an irradiation device for irradiating the applied layers of the build-up material (7) at the locations corresponding to the respective cross-section of the object, wherein the application device (6) comprises a blade arrangement guided parallel to the coating plane, consisting of a coating blade holder (11) and a coating blade (12) attached thereto.characterized in that the coating blade holder (11) is guided on both sides by side guides (15) on guide rails (20) in opposing groove-like recesses (16a) of side walls (13) above the assembly chamber (4) and the application device (6) comprises an interchangeable blade set of at least two differently designed and separately mountable coating blades (12), wherein one coating blade (12) of the interchangeable blade set is designed as a metal blade and one as a rubber blade, wherein the coating blade holder (11) is driven on both sides and the drive on both sides is effected by a common motor which synchronously drives drive elements (16) for driving the side guides (15). Device according to claim 1, characterized in that the set of interchangeable blades comprises two different rubber blades, one of which is designed with a stiffer rubber lip compared to the other rubber blade. Device according to one of the preceding claims, characterized in that the coating blade holder (11) is designed as a solid block, on the front of which a coating blade (12) can be fixed. Device according to one of the preceding claims, characterized in that the drive elements (16) are designed as toothed belts. Device according to one of the preceding claims, characterized in that a rotating drive element (16) is provided on each side of the coating blade holder (11). Device according to claim 5, characterized in that two independent parallel rotating drive elements (16) are arranged on each side of the coating blade holder (11). Device according to one of the preceding claims, characterized in that the drive elements (16) are coupled to the common motor via an angle gear. Device according to one of the preceding claims, characterized in that the side guides (15) extend beyond the front of the coating blade holder (11), in particular also beyond the front of a mounted coating blade (12), in the coating direction. Device according to one of the preceding claims, characterized in that each side guide (15) consists of a side guide base (18) connected to the lateral end sections of the coating blade holder (11) and at least one ball carriage (19) arranged below it. Device according to claim 9, characterized in that two ball carriages (19) are arranged on each side of the coating blade holder (11). Device according to claim 10, characterized in that the side guide base (18) and the ball carriages (19) arranged thereon are arranged completely in the groove-like recesses (16a) of the housing walls. Device according to one of the preceding claims, characterized in that screw fixing holes (17) arranged in the front side above the area of ​​the coating blade front exposed to the building material (7) are designed as vertically extending elongated holes. Device according to claim 8, characterized in that adjusting screws (26) are arranged on the upper side (25) of the coating blade (12), the lower ends of which are supported on a projection of the coating blade holder (11) extending into the coating blade (12) from its rear side and enable fine adjustment of the coating blade (12). Device according to one of the preceding claims 1 to 11 or according to claim 13, characterized in that the front area of ​​a mounted coating blade (12) acted upon by the building material (7) is flat and without screw fastening holes.

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