DE102009038165A1 - Device for the production of form body through layer-wise application of material powder through location-selective hardening of powder to related areas, comprises a process area with a process area base that has a base plain - Google Patents

Abstract

A device is proposed for the production of shaped bodies by building them up in layers from material powder by locally-selective solidification of the powder to form coherent areas in accordance with geometry description data of the shaped body (23), comprising - a process space (9) with a process space floor (11) which has a base plane (51 ) and has a building platform (13) that is adjustable in height relative to it, - a powder layer preparation device for preparing a powder layer (21) on the building platform (13) and - a powder solidification device, in particular an irradiation device, the powder layer preparation device being a powder supply device (55, 57, 59, 63) and a smoothing slide (43) with a powder smoothing strip (49) for distributing and smoothing the powder provided by the powder supply device in the process space (9) on the construction platform (13), the smoothing slide (43) with its powder smoothing power e (49) can be moved back and forth between two reversal points with an intermediate building platform (13) in the process room (9) in order to move the powder smoothing strip (49) at a distance (essentially) corresponding to the desired powder layer thickness from the previous step on the building platform (13) to move a layer of solidified powder over the construction platform (13) in a location-selective manner, with the powder supply device being attached to an outside of the process space (9) ...

Description

• – einen Prozessraum mit einem Prozessraumboden, der eine Basisebene und eine relativ dazu mittels einer steuerbaren Antriebseinheit längs einer vertikalen Bauplattformachse gesteuert höhenverstellbare Bauplattform für den Formkörper aufweist,
• – eine Pulverschichtenpräparierungseinrichtung zur Präparierung einer jeweiligen nachfolgend ortsselektiv zu verfestigenden Pulverschicht auf der Bauplattform und
• – eine Pulververfestigungseinrichtung, die zum ortsselektiven Verfestigen von Pulver der jeweils zuletzt auf der Bauplattform präparierten Pulverschicht aktivierbar ist,

wobei die Pulverschichtenpräparierungseinrichtung eine Pulverversorgungseinrichtung zur Bereitstellung von Pulver in dem Prozessraum und einen Glättungsschieber mit einer Pulverglättungsleiste zur Verteilung und Glättung des von der Pulverversorgungseinrichtung im Prozessraum bereitgestellten Pulvers auf der Bauplattform aufweist, wobei der Glättungsschieber mit seiner Pulverglättungsleiste zwischen zwei Umkehrstellen mit in Draufsicht dazwischenliegender Bauplattform im Prozessraum hin- und herbewegbar ist, um die Pulverglättungsleiste in einem der gewünschten Pulverschichtdicke entsprechenden Abstand zu der im jeweils vorausgegangenen Schritt auf der Bauplattform ortsselektiv verfestigten Pulverschicht über die Bauplattform hinwegzubewegen.The invention relates to a device for the production of moldings by layer-wise building up of material powder by locally selective solidification of the powder to coherent areas in accordance with Geometriebeschreibungsdaten of the molding comprising

• A process space having a process space bottom, which has a base plane and a height-adjustable construction platform for the shaped body controlled in a controlled manner by means of a controllable drive unit along a vertical construction platform axis,
• A powder layer preparation device for preparing a respective subsequently location-selectively solidified powder layer on the building platform and
• A powder hardening device which can be activated for site-selective solidification of powder of the last powder layer prepared in each case on the building platform,

wherein the powder layer preparation device has a powder supply device for providing powder in the process space and a smoothing slide with a powder smoothing strip for distributing and smoothing the powder provided on the construction platform by the powder supply device in the process space, the smoothing slide with its powder smoothing strip being located between two reversal points with a construction platform in between Process chamber is moved back and forth to the powder smoothing bar in a desired powder layer thickness corresponding distance to the spatially in the respective previous step on the build platform solidified powder layer over the build platform move away.

such Devices for the production of moldings are in various configurations known. Basic differences between known devices This type arise from the mode of action of the powder hardening device. So there are devices in which the powder compaction by site-selective application of a binder or chemical reactant on the last prepared on the build platform Powder layer is made to these at the relevant sites too coherent Solidify areas that solidified with accordingly Connect areas to the underlying layer.

However, in recent years, another working principle has been found to be of particular interest in the site-selective solidification of powder, namely solidification by remelting or, if appropriate, sintering of the powder by energy input by radiation, in particular laser radiation. The mode of remelting the powder is referred to in the present application as selective laser melting. Selective laser melting is used to produce shaped bodies of metallic powders and / or ceramic powders. The devices used for this purpose are also referred to as SLM devices and are known in various variants, such. B. from the DE 10 2004 041 633 A1 , of the DE 102 36 907 A1 , of the DE 199 05 067 A1 , of the DE 10 112 591 A1 or the WO98 / 24574 A1 , These SLM devices are used to produce a shaped body according to geometric data, in particular CAD data, the shaped body by layering of powdered, metallic or ceramic material, wherein successively more powder layers are applied one above the other and each powder layer before applying the next powder layer with a focused laser beam in a predetermined area corresponding to a selected cross-sectional area of the molding is heated. The laser beam is guided in each case in accordance with the CAD cross-sectional data of the selected cross-sectional area of the molded body or data derived therefrom via the respective powder layer. As a result of the energy input of the laser radiation, the material powder is locally remelted in the region of the point of impact of the laser beam so that contiguous regions arise as homogeneously as possible of remelted material in the respective layer. Superimposed remelted areas of two successive layers combine, so that the shaped body arises coherently layer by layer.

The Quality of the preparation of the construction platform successive powder layer in the sense of keeping a respective predetermined layer thickness and the creation of a respective even powder layer surface plays an essential role in selective laser melting, because they are the homogeneity of the material melted and re-solidified from the powder of the shaped body determined. This applies to both the production of a shaped body according to the principle of selective laser melting as well as in the production of a shaped body according to the principle of selective laser sintering, in which the powder material not completely melted, but at the irradiated Places is sintered. Usually, multicomponent powder materials are used used, which have different melting points.

The preparation of a respective new powder layer on the construction platform should take as little time as possible, irrespective of the powder consolidation principle used, so that the construction process of the molding as a whole can take place as quickly as possible. To meet these requirements, namely the rapid production a homogeneous plane powder layer of the desired powder layer thickness, various layer preparation devices have been proposed.

In the device according to the DE 102 36 907 A1 For example, the layer preparation device has a powder dispenser in the form of a cartridge housing with a chamber for receiving a supply of powder. The powder dispenser is co-moving part of a smoothing slide and has on its underside a continuous powder discharge slot and two powder smoothing ledges made of silicone or the like. The powder smoothing ledges are parallel to each other and form a common lowest level of the layer preparation device. The powder discharge gap runs between the two smoothing slides. For the preparation of a powder layer, the distance between the lower surfaces of the two smoothing slides is first of all processed to the last. Layer adjusted to the degree of the desired powder layer thickness to be produced. Then, the layer preparation device is moved away in compliance with this distance measure over the build platform and thus over the last processed layer. In this case, powder is discharged from the co-moving powder dispenser through the lower discharge gap and distributed and leveled by means of the smoothing slide rail. The amount of powder provided per layer is predetermined by a metering shaft entrained in the powder dispenser.

at the further development of the technology considered here in particular selective laser melting (SLM) and the extension of the process to the use of a variety of different powder materials, such as As gold, aluminum, titanium, cobalt-chromium, etc., it has shown that the powder materials z. B. very different flowable or are capable of crystallization and that in particular in relation on the flow properties of some powder materials yet Need for optimization in the means for layer preparation consists. Some powders have a very good flowability shown so that at layer preparation facilities occasionally too large quantities without single dosing agent such powders at each layer preparation step were issued. In contrast, other powder materials showed a tendency to clumping in the powder dispenser housing, so that over the known output gap of such layer preparation devices no uniform powder flow is output could. This has the quality of the prepared Layers impaired.

It Solutions have also been proposed in the prior art in which a larger supply of material powder on a reciprocating piston in a cylinder hole of the process room floor deposited for the building process of a molding is, wherein the lifting piston in each case synchronously with the lowering movement the building platform after the site-selective consolidation of the previous one Powder layer is raised by a corresponding amount, a small amount of powder above the height level lift the base level of the process room floor, this amount of powder then pushed by a smoothing slider to the build platform and there distributed to a uniform layer becomes. This principle of powder feed through a with the lowering of the platform platform corresponding piston stroke in the powder storage cylinder has proved to be less flexible in terms of Any desired variations of the respectively supplied Amount of powder per powder preparation step and in terms of the temporal optimization proved.

Of the present invention is based on the object, a device of the type mentioned above with a novel layer preparation device to provide, which for the preparation of layers from powder materials of different flowabilities with good results regarding the quality of each Layers is usable, has a simple construction and a fast Execution of the respective layer preparation allows.

These The object is achieved according to the invention that a device of the type mentioned above equipped with a powder supply device which is provided at an outside of the process room Powder reservoir connected or connectable Powder supply channel and a conveyor for conveying of powder in the powder feed channel, especially during the phases in which the Pulververfestigungseinrichtung for site-selective Solidification of powder last each on the build platform prepared powder layer is activated, wherein the powder supply channel at least one between the build platform and one of the reversal points of the powder smoothing bar lying powder inlet point opens into the process room, to direct powder directly to the process room floor.

The powder feed duct directs the powder conveyed by the conveyor directly to the process room floor. A powder dispenser as a moving part of the smoothing slide, such as from DE 102 36 907 A1 is not required in the device according to the present invention. This has the advantage that the smoothing slider has a significantly lower mass and thus a significantly lower inertia, so that it can be moved quickly across the construction platform with a comparatively weak movement drive in order to prepare a new powder layer. The temporal optimization comes Also benefit that the powder supply to the process space floor can take place in the phases in which the powder hardening device is activated for the site-selective solidification of each last prepared on the building platform powder layer. Immediately after completion of the Pulververfestigungsschritt or possibly even slightly earlier, the smoothing slide can already be set in motion to distribute the powder already available in front of the Pulverglättungsleiste over the meantime lowered by the level of the desired powder layer thickness building platform. The forced delivery of the powder through the powder feed channel provides trouble-free replenishment of the particular powder amount desired for the current layer preparation step, essentially regardless of the type and flowability of the powder used.

In a particularly preferred embodiment of the invention the powder feed channel opens at one between the build platform and one of the reversal points of the powder smoothing bar lying powder inlet point from below into the process room floor. In this preferred case, the conveyor pushes thus the respectively desired amount of powder from below in the process room. The then set in motion smoothing slider decreases then the powder by means of Pulverglättungsleiste to Bauplattform with it to get it there in an even layer the desired thickness.

For the powder delivery in the powder guide channel towards the process room has a screw conveyor proved to be particularly suitable, the one in the powder feed channel having provided screw conveyor. The powder feed channel can z. B. a pipe or optionally a powder feed hose of flexible material.

Preferably If the device according to the invention is an SLM device, in which the powder solidification device is an irradiation device having a radiation source, in particular a laser radiation source, whose radiation is to be directed to the building platform in a location-selective manner, powder of a respective last prepared powder layer to remelt to coherent areas. According to one Another embodiment of the invention is the device designed to carry out the procedure of selective laser sintering.

Preferably is the build platform relative to the base level of the process space floor each to the extent of a desired powder layer thickness lowered into a new Absenkstellung to a respective new powder layer further including the underside of the powder smoothing bar essentially at the level of the base level of the process room floor is arranged, in particular with the latter has contact. How later is still explained, the build platform for each Preparation of a powder layer still controlled vertically be moved to the size of the beam impact point in the case of irradiation with a focused laser beam on the Adjust powder layer and / or possibly even during of the irradiation process to vary.

Regarding the embodiment of the smoothing slide has a Embodiment has been found particularly suitable, this embodiment of the smoothing slide another powder smoothing bar has, at a horizontal distance to the first Pulverglättungsleiste at the same height with this runs, leaving the powder smoothing strips limit an open space to the process room floor, wherein the smoothing slider with its powder smoothing strips in a powder replenishment waiting position next to the build platform like that can be positioned that the powder inlet point in the space opens. Also applies to this case, that one particularly preferred embodiment of the invention a Powder inlet point provided in the process room floor, to the powder from below into the process space and in particular in the space between the Pulverglättungsleisten contribute. With the float of the smoothing slider Any excess remains, not on the build platform deposited powder at least largely in the Space between the powder smoothing strips and is thus prevented from polluting the process room uncontrolled.

The Powder inlet can be a z. B. round mouth hole the powder supply channel with a relatively small diameter be. In particular for this case it is suggested that the Pulverglättungsleisten in plan view the shape of bows that are in the powder refilling waiting position of the smoothing slider towards the building platform axis convex are. Such a particularly preferred solution has the advantage that during the movement of the smoothing slider from the powder replenishment waiting position out in the direction of the build platform which, in the first place, is essentially concentrated on the area of the relatively small powder intake point replenished amount of powder rapidly over a wider range the trailing smoothing bar is distributed so that the smoothing bar overflows powder material to a sufficient width distribute the build platform.

During the return movement of the smoothing slide, due to the curved shape of the smoothing slide bars, excess powder tends to collect again on a narrower peak area of the then trailing smoothing slide. Again, this is a measure that is uncontrollable te contamination of the process space by excess powder to avoid.

Of the Powder conveyor is equipped with an electronic control device the device preferably so controllable that it has a respective predetermined amount of powder for preparation a respective subsequently to be solidified powder layer in brings in the process space. The amount of powder should be dosed be that they are responsible for the preparation of the concerned Just enough powder layer, leaving little excess Powder in the process room is to handle. As mentioned above, the powder feed is preferably carried out when the smoothing slide is in his powder replenishment waiting position, in a respective phase of powder compaction by means of the powder compaction device; in the Trap of selective laser melting during the irradiation phases the powder layer.

In Reference to the problem of as clean as possible powder handling in the process room is according to another aspect of the invention suggested that in a device with the features of The preamble of claim 1 or in a device according to one of claims 1-8 a powder suction for the extraction of excess powder from the Construction platform after completion of a respective molding is provided, wherein the suction device comprises a suction cup, the in the process room on the construction platform is inverted and the via suction lines with an external collection container connected is. For sucking a pump is activated, which the required negative pressure generated in the suction cup and the powder over sucks the suction lines. This may, if necessary, in a protective gas atmosphere respectively. The inner volume of the suction cup can be compared with the Inner volume of the process space are usually kept small.

Preferably is the construction platform with überülülter suction bell at least approximately to the base level of the process room floor or in addition, be lifted, in particular during a Pulverabsaugvorganges, so a respective shaped body in the suction bell and bring him of excess powder to free.

It a powder loosening device may be provided to the Loosen the powder to be sucked on the build platform. The powder loosening device can z. B. a construction platform vibrating vibrating device, in particular be ultrasonic vibrator.

To Completion of a suction should be the molded body produced of excess powder on its outside be largely free. The suction bell can then be released again or possibly with protective gas, to equalize the pressure to produce with the environment in the process room. The handling of Suction bell can manually z. B. using a penetration permitting by a process chamber housing wall opening Sealing glove done. Alternatively, the handling of the suction bell also automatically, z. B. by means of a robotic device or the like. respectively.

the Aspect of the powder extraction by means of a Pulverabsaugglocke comes possibly independent significance too.

This also applies to the following aspect of the invention, the variation of the height adjustment of the construction platform for the purpose of modifying the size of the beam impact point of the focused laser beam on the respectively last-prepared powder layer. In this regard, a device according to the preamble of claim 1 or any one of claims 1 to 12 is proposed, wherein the powder compaction device comprises an irradiation device with a radiation source, in particular laser radiation source, the radiation is directed to the building platform to selectively site powder to each last on it melted or sintered prepared powder layer to contiguous areas, wherein the device according to the invention is characterized in that the radiation of the radiation source in the form of a focused beam, in particular focused laser beam, is directed to the build platform, wherein the build platform by means of the controllable drive unit between each other directly The following powder layer preparation operations relative to the focal point or the focal plane of the focused beam is vertically adjustable to the size of the beam impact point on the last on the B auplattform prepared powder layer to vary. By varying the size of the beam impingement point, the respective energy density, that is to say the radiation impinging on the impingement site per unit area and time unit, can be varied. The highest energy density is usually obtained when the surface of the prepared powder layer is in the focal plane of the focused beam. In this case, very high temperatures can be reached quickly at the jet impact point. However, the beam impact point has a very small extent. Especially with low-melting powder materials, it is not necessary to use such a high energy density when scanning the powder layers with the focused beam at the sites to be solidified. Rather, it may make sense to scan the powder layer with a somewhat "defocused" jet. This beam then has a somewhat larger extent of the beam impingement point, so that in each case a wider scanning track can be generated when scanning the powder layer. That is have already been used in the past. However, adjustable optical elements, in particular lenses in the beam path of the irradiation device, have been provided for realizing these focusing or defocusing possibilities, and these optical elements are then controlled in such a way that they adjust the size of the beam impact point to the last powder layer prepared on the building platform in the desired manner.

The Device according to the present invention comes without such additional control of optical components by They the already existing controllable drive unit for uses the vertical drive of the build platform to focus / defocus the Pulververfestigungsstrahles the construction platform in the desired Set way. This can be done just before the start of each Irradiation process done.

If necessary, can the construction platform by means of the controllable drive unit relative to the focal point or the focal plane of the beam but also during the process of site selective irradiation of the last on the Construction platform prepared powder layer controlled adjustable be the size of the beam impact point ever according to the coordinates of the beam impact point on the powder layer to vary in the desired manner. This possibility has proven to be particularly beneficial for a quick and even Construction process of a shaped body proved. The invention is thus also under the process aspect of Fokalverstellung due the variable height adjustment of the construction platform interesting.

embodiments The device according to the invention will be referred to below explained in more detail on the figures.

1 shows in a perspective view of an SLM device according to the invention in an external view.

2a and 2 B show in a crude schematic way a snapshot during the process of irradiation of the last prepared powder layer on the build platform.

3a and 3b show in a rough schematic representation of a Pulverabsaugglocke over the build platform at different height settings of the build platform.

4a . 4b and 4c show in a perspective view of the process space compartment of the device 1 in a largely disassembled state to reveal the view of a layer preparation device incorporated in the 4a - 4c shown in different settings.

5 shows a plan view of a layer preparation device and the process space bottom of a SLM device according to the invention.

6 shows a further embodiment of a layer preparation device for a SLM device according to the invention in a perspective view, as similar in the 4a - 4c has been used.

7 shows an SLM device of in 6 shown type, but with a modified form of Pulverglättungsleisten.

1 shows as an example of a SLM device a SLM table device, which z. B. for the production of dental prostheses, jewelry, small machine parts, etc. may be used and in particular for the field of research on processes in selective laser melting (SLM) or possibly in selective laser sintering (SLS) is suitable.

The SLM device 1 has a housing 3 with a process room compartment 5 and a supply compartment 7 on. In the process room compartment 5 is the process room 9 with his process room floor 11 and the built-in platform 13 like this through the viewing window 15 in the front housing wall of the process room compartment 5 can be seen. A stereo microscope 17 can be used to observe the SLM building process and / or setting certain parameters, such as B. Check the focal position of the laser beam used. In the opposite side walls of the process room compartment 5 are passage openings 19 provided, which are sealed by a designated Durchgriffs glove (not visible) to the outside. The process room compartment 5 is thus designed as a glove box and allows manual access to components in the process room 9 from the outside. During the building process of a molded article prevails in the process room 9 preferably inert gas atmosphere.

In the supply compartment 7 Among other things, components for the protective gas supply, components of the electronic control of the device and electrical components are provided.

In 2a is in a crude schematic way, a snapshot during the irradiation of a last on the build platform 13 prepared powder layer 21 shown. Starting from a first layer of powder on a substrate plate 25 has been prepared, the construction process of the molding 23 started and then layer by layer up to the in 2a indicated snapshot has been continued. The powder used is z. As metal powder or possibly ceramic powder. After the preparation of a respective powder layer on the build platform 13 this is done by means of a laser beam 27 Site-selective irradiated at the points where the powder is to be remelted to contiguous solidified areas. The laser beam 27 scans the current layer to be irradiated 21 in a controlled manner from, for this purpose z. B. an XY Galvanoscanner 29 is used. Furthermore, the control device controls the switch-on / switch-off phases of the laser beam 27 ,

According to 2a is the laser beam 27 so focused that its focal point 31 at the surface of the powder layer 21 lies. The beam impact point 37 is thus extremely small at this point and the energy density of the laser beam in Strahlauftreffpunkt is very high.

According to one aspect of the present invention, the size of the beam impact point 37 and thus its energy density can be varied by that in a cylinder guide 33 along the vertical axis 35 controlled movable construction platform 13 is varied in their height adjustment. 2 B shows the example case that the build platform 13 after preparation of the current layer to be irradiated 21 by a Absenkmaß Y from the focal point 31 of the laser beam 27 has been lowered so that the laser beam 27 at the beam impact point 37 on top of the powder layer to be irradiated 21 again something is widened compared to the situation according to 2a , The beam impact point 37 on the powder layer to be irradiated 21 in 2 B has thus become larger and has less energy per unit area than the focal point corresponds to the beam impact point 37 in 2a , By appropriate height adjustment of the construction platform 13 Thus, the size of the Strahlauftreffpunktes on the powder layer to be irradiated 21 be varied during the irradiation process, if desired. On the other hand, it is also possible that in each case at the beginning of a layer irradiation process, this focal adjustment or defocus by appropriate height adjustment of the construction platform 13 he follows.

In the 4a - 4c is the process space area of the 1 recognizable SLM device shown, wherein the housing 3 is shown in the largely disassembled state to the view of the Pulverschichtpräparierungseinrichtung 41 release. This includes a smoothing slider 43 , which is formed as a pivot arm, which is about a vertical pivot axis 45 between the in 4a shown first reversal position and the in 4c shown second reversing position is swinging back and forth. In such a pivoting movement of the smoothing slider passes 43 the build platform 13 in the process room floor 11 to get a smooth layer of powder on the build platform 13 to create. The smoothing slider has for this purpose two Pulverglättungsleisten 47 . 49 made of silicone or the like., The undersides on the base level 51 of the process room floor 11 lie. The two powder smoothing strips 47 . 49 limit between them a downwardly open space 53 in which the smoothing slider 43 Powder to building platform 13 can transport. The powder is introduced into the process space by means of a powder supply device 9 promoted. The supplied powder is passed through a powder inlet or powder inlet 55 in the process room floor 11 from below into the process room 9 brought in. The powder inlet opening 55 is located at a location between the build platform 13 and the in 4a reversal point of the smoothing bar 49 , More specifically, the powder inlet port is located 55 exactly under the gap 53 between the powder smoothing strips 47 . 49 when the smoothing slider 43 in the in 4a The reverse position shown is also a powder replenishment waiting position of the smoothing slider 43 is.

After feeding a metered amount of powder into the space 53 Control of the SLM device causes the smoothing slider 43 to, from the in 4a shown inversion position in the in 4c to pivot shown reversing position, so that the case of the trailing Pulverglättungsleiste 49 advanced powder to the build platform 13 arrives. The construction platform 13 is previously the measure of the desired powder layer thickness in its cylinder guide 33 been lowered. Because the smoothing bars 47 . 49 with their bases on the base level 51 of the process room floor 11 lie, is when painting the construction platform 13 thus producing a smoothed powder layer of the desired thickness. The smoothing slider 43 then returns to the powder replenishment waiting position (reverse position) according to 4a , And it can start the irradiation process for the site-selective solidification of the previously prepared powder layer.

During the irradiation process, a next dose of powder may already pass through the powder inlet 55 in the gap 53 of the smoothing slider 43 for the preparation of the next layer of powder on the build platform 13 be encouraged. The powder is for this purpose from an external reservoir 57 the powder mixing point 55 fed, one below the process space floor 11 extending powder feed channel the powder inlet point 55 with the reservoir 57 combines. In the powder feed channel, a screw conveyor is rotatably received, which is controlled by a controllable electric motor 59 is driven to rotate to the powder from the Vorratsbe container 57 out to the powder club booth 55 zwangszufördern.

The processes of the powder layer preparation on the building platform 13 and the site-selective solidification by irradiation of the powder repeat each other until the desired shaped body 23 is completed. The leadership of the laser beam 27 during its scanning movement over the build platform 13 takes place in a known manner in accordance with Geometriebeschreibungsdaten of the molding in each case concerning the currently irradiated layer.

In the 4a - 4c is another hole 61 in the process room floor 11 recognizable. This serves to remove excess powder from the process room floor 11 dissipate. This can be done manually using the sealing gloves (not shown) at the access openings 19 done with a sweeping tool or the like.

In 5 is a plan view of the process room floor 11 and the smoothing slider 43 of an SLM device according to the invention, which only in nuances, which are insignificant for the present description, of the SLM device according to the 4a - 4c differs. Elements in 5 , the elements in the 4a - 4c represent objectively or functionally, are marked with corresponding reference numerals, so that for understanding the SLM device in 5 largely to the description of the SLM device according to 4a - 4c can be used. In 5 is with dashed lines of the process room floor hidden powder feed channel 63 indicated. He opens with the powder intake point 55 from below into the process room floor 11 , The smoothing slider 43 is located in 5 in the reversal position or powder replenishment waiting position, so that the powder inlet point 55 exactly in the gap 53 between the powder smoothing strips 47 and 49 leads.

The powder smoothing strips 47 and 49 have in the plan view according to 5 the shape of sheets that in the shown powder replenishment waiting position of the smoothing slider towards the building platform 13 are convex. Because of this arch shape, there is a rapid distribution of the over the relatively narrow powder inlet 55 supplied powder along the Pulverglättungsleiste 49 when the smoothing slider 43 towards the build platform 13 is pivoted. When the smoothing slider 43 after the relatively small tilt angle the build platform 13 has reached, the powder is in the gap 53 already well-distributed, making it evenly over the build platform 13 in the further pivoting movement of the smoothing slide 43 can be elapsed. During the return movement of the smoothing slider 43 then comes the arcuate curvature of Pulverglättungsleiste 47 to act by tending to recycle any excess powder directly to the powder inlet site 55 collecting converging peak area of the arc out. The excess powder can be well in the gap in this way 53 be kept, so that uncontrolled pollution of the process space floor 11 can be largely avoided with excess powder during the construction process.

The powder layer preparation device of the device according to the invention according to 4a - 4c and 5 allows a reliable supply of powder to the process room, regardless of the type and flowability of the powder. It also ensures fast and high-quality powder coating preparation on the build platform 13 ,

In the 6 and 7 two further embodiments of an SLM device according to the invention are shown in partial view. Notwithstanding the embodiments already described, the powder feed channel opens 63a in the examples of 6 and 7 not from below into the process room 9 but at a point above the process room floor 11 , An upper powder feed channel 63a is sealed by an opening in the rear wall of the housing 64 guided. The powder intake point 55a is through a vertically from the tubular powder feed channel 63a defined downwardly projecting tube, which from above into the open space above 53 between the two powder smoothing strips 47 . 49 flows when the smoothing slider 43 in the in the 6 and 7 shown is powder replenishment waiting position. After dispensing a metered amount of powder into the space 53 becomes the smoothing slider 43 over the build platform 13 pivoted away to prepare a respective powder layer, as already explained with reference to the preceding embodiments.

In the device according to 6 are the powder smoothing strips 47 . 49 in reference to 5 curved as described, while the device according to 7 two straight and parallel Pulverglättungsleisten 47 . 49 having.

To explain a further aspect of the invention is on the 3a and 3b Referenced. It shows schematically how after completion of a molding 23 a Pulverabsaugglocke 69 over the build platform 13 is slipped. The powder suction bell 69 is shown partially broken away to make the interior volume recognizable. In 3a is the construction platform 13 still in a lowered state in which the too last prepared powder layer 21 essentially flush with the base plane 51 of the process room floor 11 lies. In 3b is the build platform 13 shown in a raised state, wherein the powder thereon and the built-up shaped body 23 in the inner volume of the suction cup 69 are included. That the shaped body 23 outside surrounding excess powder can be sucked off so efficiently. This is done via the suction line 71 , which is connected to a suction pump. The extracted powder enters a screening device. The sieved powder then passes into a storage container for reuse.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 102004041633 A1 [0003]
• - DE 10236907 A1 [0003, 0006, 0011]
• - DE 19905067 A1 [0003]
• - DE 10112591 A1 [0003]
• WO 98/24574 A1 [0003]

Claims (15)

Apparatus for the production of shaped bodies by layer-wise building up from material powder by locally selective solidification of the powder to coherent areas in accordance with geometry description data of the shaped body ( 23 ), comprising - a process space ( 9 ) with a process room floor ( 11 ); the one basic level ( 51 ) and a relative thereto by means of a controllable drive unit along a vertical building platform axis ( 35 ) controlled height adjustable build platform ( 13 ) for the shaped body ( 23 ), - a Pulverschichtpräparierungseinrichtung for preparing a respective subsequently selectively to be solidified powder layer ( 21 ) on the build platform ( 13 ) and - a powder hardening device, which is used for site-selective solidification of powder last on the building platform ( 13 ) prepared powder layer ( 21 ) is activatable, wherein the powder layer preparation device ( 41 ) a powder supply device ( 55 . 57 . 59 . 63 ) for providing powder in the process space ( 9 ) and a smoothing slider ( 43 ) with a powder smoothing strip ( 49 ) for distributing and smoothing the powder supply device in the process space ( 9 ) provided powder on the build platform ( 13 ), wherein the smoothing slider ( 43 ) with its powder smoothing strip ( 49 ) between two reversal points with a building platform in between ( 13 ) in the process room ( 9 ) is reciprocable to the Pulverglättungsleiste ( 49 ) in a desired powder layer thickness corresponding distance to that in the previous step on the build platform ( 13 ) location-selectively solidified powder layer over the build platform ( 13 ), characterized in that the powder supply means one at an outside of the process space ( 9 ) provided powder reservoir ( 57 ) connected or connectable powder feed channel ( 63 ) and a conveyor for conveying powder in the powder supply passage (FIG. 63 ), in particular during the phases in which the powder consolidation device for the site-selective solidification of powder of the respectively last powder layer prepared on the building platform (US Pat. 21 ) is activated, wherein the powder feed channel ( 63 ) at least one between the build platform ( 13 ) and one of the reversal points of the powder smoothing strip ( 49 ) powder inlet point ( 55 ) in the process room ( 9 ) to powder directly to the process room floor ( 11 ). Apparatus according to claim 1, characterized in that the powder feed channel ( 63 ) at least one between the build platform ( 13 ) and one of the reversal points of the powder smoothing strip ( 49 ) lying powder inlet point from below into the process room floor ( 11 ) opens. Apparatus according to claim 1, characterized in that the conveyor is a screw conveyor, one in the powder feed channel ( 63 . 63a ) has provided screw conveyor. Apparatus according to claim 1, 2 or 3, characterized in that the powder hardening device comprises an irradiation device with a radiation source, in particular a laser radiation source whose radiation is spatially selective to the construction platform ( 13 ) is to powder of each last prepared thereon powder layer ( 21 ) to remix or sinter into coherent areas. Device according to one of the preceding claims, characterized in that the construction platform ( 13 ) relative to the base plane ( 51 ) of the process room floor ( 11 ) can each be lowered by the amount of a desired powder layer thickness to a new lowered position, in order to receive a respective new powder layer, and that the underside of the powder smoothing strip is essentially at the level of the base plane ( 51 ) of the process room floor ( 11 ) is arranged. Device according to one of the preceding claims, characterized in that the smoothing slide ( 43 ) another powder smoothing bar ( 47 ) spaced horizontally from the first powder flattening bar (FIG. 49 ) runs at the same height with this, so that the Pulverglättungsleisten ( 47 . 49 ) one to the process room floor ( 11 ) open space ( 53 ), whereby the smoothing slider ( 43 ) with its powder smoothing strips ( 47 . 49 ) in a powder replenishment waiting position next to the building platform ( 13 ) is positionable so that the preferably in the process room floor ( 11 ) provided powder inlet point ( 55 ) into the space ( 53 ). Apparatus according to claim 6, characterized in that the Pulverglättungsleisten ( 47 . 49 ) in plan view have the form of sheets which are in the powder replenishment waiting position of the smoothing slide ( 43 ) towards the building platform axis ( 35 ) are convex. Device according to one of the preceding claims, characterized in that the conveyor is controllable to a respective predetermined amount of powder for the preparation of a respective subsequently to be solidified powder layer in the process space ( 9 ). Device according to the preamble of An Claim 1 or according to one of the preceding claims, characterized in that a powder extraction device ( 69 . 71 ) for the extraction of excess powder from the building platform ( 13 ) after completion of a molding ( 23 ) is provided, wherein the suction device ( 69 . 71 ) comprises a suction cup, which in the process space ( 9 ) over the build platform ( 13 ) and the via suction lines ( 71 ) is connected to an external collection container. Apparatus according to claim 9, characterized in that the building platform ( 13 ) with überülülter suction bell ( 69 ) at least approximately to the base level ( 51 ) of the process chamber floor is liftable, in particular during a Pulverabsaugvorganges so as to a respective shaped body ( 23 ) in the suction bell ( 69 ) and to rid him of excess powder. Device according to one of claims 9 or 10, characterized in that the powder suction a Powder loosening device comprises. Device according to claim 11, characterized in that that the powder loosening device a the building platform in Vibratory vibrating device, in particular ultrasonic vibrator having. Device according to Claim 4 or according to a claim dependent thereon, characterized in that the radiation of the radiation source is in the form of a focused laser beam ( 27 ) on the build platform ( 13 ), the building platform ( 13 ) by means of the controllable drive unit immediately after each powder layer preparation operation relative to the focal point ( 31 ) or the focal plane of the laser beam ( 27 ) is vertically adjustable to the size of the Strahlauftreffpunktes ( 37 ) on the last on the build platform ( 13 ) prepared powder layer to vary. Apparatus for the production of shaped bodies by layer-wise building up from material powder by location-selective solidification of the powder to coherent areas in accordance with geometry description data of the shaped body, comprising - a process space ( 9 ) with a process room floor ( 11 ), which is a base level ( 51 ) and a relative thereto by means of a controllable drive unit along a vertical building platform axis ( 35 ) controlled height adjustable build platform ( 13 ) for the shaped body ( 23 ), - a Pulverschichtpräparierungseinrichtung for preparing a respective subsequently selectively to be solidified powder layer ( 21 ) on the build platform ( 13 ) and - a powder hardening device, which is used for site-selective solidification of powder of the last powder layer prepared on the building platform ( 21 ), wherein the powder hardening device has an irradiation device with a radiation source, in particular a laser radiation source, the radiation of which is spatially selective to the construction platform (US Pat. 13 ) in order to remelt or sinter powder of a respective powder layer which has been lastly prepared thereon to coherent regions, the radiation of the radiation source being in the form of a focused beam ( 27 ) on the build platform ( 13 ), characterized in that the building platform ( 13 ) by means of the controllable drive unit immediately after each powder layer preparation operation relative to the focal point ( 31 ) or the focal plane of the beam ( 27 ) is vertically adjustable to the size of the Strahlauftreffpunktes ( 37 ) on the last on the build platform ( 13 ) prepared powder layer to vary. Apparatus according to claim 13 or 14, characterized in that the building platform ( 13 ) by means of the controllable drive unit relative to the focal point ( 31 ) or the focal plane of the beam during the process of the location-selective irradiation of the last on the build platform ( 13 ) prepared powder layer ( 21 ) is controlled to the size of the beam impact point ( 37 ) on the powder layer ( 21 ) to vary.

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