DE20318721U1 - Rapid prototyping assembly has a carrier, within a housing, where powder layers are built up in succession to be melted or sintered, with a side door at the process zone housing for horizontal access into the zone - Google Patents

Abstract

To form a shaped body, successive layers are built up using a metal or ceramic powder. A carrier (10) for the layer build-up is within a process zone housing (2), and an optical structure (6) is for a focused laser to melt or sinter the previously laid powder layer. A charging unit (52) prepares the powder material for the next layer to be deposited as a combined delivery and layer smoothing unit. The housing has a side door for a horizontal access to its interior through a door opening (4).

Description

The invention relates in particular to an apparatus for the production of a shaped article according to the preamble of claim 1. The invention relates in particular to the field of selective laser melting and proceeds both procedurally and device-wise from a technology such as that described in US Pat DE 199 05 067 A1 , in the DE 101 12 591 A1 , in WO 98/24574 or in the corresponding DE 196 49 865.1 although the invention is also applicable to the field of laser sintering.

at The technology considered here is about a device for Production of a shaped body, e.g. a prototype of a product or component, a tool or a spare part, according to three-dimensional CAD data a model of the molding by layering of powdered, metallic or ceramic Material in which successively several layers of powder on top of each other be applied, each powder layer before application the next Powder layer with a focused laser beam in a given Area of a selected one Cross-sectional area of the model of the molding corresponds, is heated and wherein the laser beam respectively corresponding to the CAD cross-sectional data of the selected Cross-sectional area of the model or data derived from it respective powder layer is guided. The material powder is used as a binder in selective laser melting. and flux-free, metallic, ceramic or mixed metallic / ceramic Material powder applied and by the laser beam to melting temperature heated, with the energy of the laser beam being selected that the material powder at the point of impact of the laser beam over its entire layer thickness as possible Completely is melted. about the zone of interaction between the laser beam and the metallic one Material powder is maintained in a protective gas atmosphere.

The Devices contemplated herein are also referred to as rapid prototyping devices or Selected devices for selective laser melting.

task The invention is to simplify the construction of such a device and to improve the operation.

These Task is governed by the objects of claims 1, 15 and 16 solved. Further developments of the invention are specified in the subclaims. The invention will be described below with reference to the figures explained in more detail.

1 shows in a perspective view of a contiguous mounted assembly of a rapid prototyping device according to the invention.

2 shows the rapid prototyping device in one of 1 corresponding perspective view, but with removed process room front door and with removed process room front door and with removed cover of the optical attachment.

3 shows the assembly 2 in a front view.

4 shows a side view of the arranged above an intermediate plate components of the assembly of the 1 - 3 ,

5a and 5b show in a perspective view with a view from above or with a view from below a coater from the process space of the rapid prototyping device according to the invention.

• – Prozessraumgehäuse 2,
• – Optikaufsatz 6,
• – Elevatoranordnung 8 für eine Bauplattform 10 im Prozessraum 4,
• – Pulvernachfülleinrichtung 12.

The assembly shown in the figures comprises the following main components:

• - Process room housing 2 .
• - Optics attachment 6 .
• - Elevator arrangement 8th for a build platform 10 in the process room 4 .
• - Powder replenisher 12 ,

The production of a shaped article by layer-wise remelting of powder, for example metal powder, ceramic powder or multi-component powder, takes place in the process space 4 which of the process space housing 2 is defined. The process space housing 2 includes a lower box part 14 out of ground 16 , Side walls 18 . 20 , Rear wall 22 and rear part cover 24 as well as upper side walls 26 . 28 and an upper attachment back wall 30 , Locked is the process room 2 at its top by the base plate 32 of the optics tower 6 , The upper extension walls 26 . 28 . 30 are plug-in construction walls, which (not shown) on their lower narrow sides downwardly projecting dowel projections in (not shown) complementary recesses in the upper narrow sides of the box side walls 18 . 20 are plugged in. By means of such connectors is also the optical attachment 6 on the side walls 26 . 28 and the back wall 30 attached to the upper narrow sides.

According to 1 is a front door 34 for closing the process space 4 on the process space housing 2 intended. It is at the front door 34 around a hinged door, which by means of hinge hinges 36 on the side wall 18 . 26 is pivotally mounted and by means of two Ver closing facilities 38 in the in 1 shown closed position can be locked.

As in 2 recognizable, the bottom plate 16 of the process chamber housing 2 an opening 40 on, in which the build platform 10 can be seen for each shaped body to be produced. The construction platform 10 is in a hollow base 42 controlled vertically adjustable. As an adjustment drive for the construction platform 10 is the elevator 8th with a spindle drive 44 and with a stepper motor 46 intended. When activating the stepper motor 46 and the spindle drive 44 There is a vertical displacement of the bottom through an opening in the frame plate 48 into the hollow base 42 upwardly projecting Bauplattformträgers 50 , On the building platform carrier 50 the construction platform sits 10 ,

In the process room housing 2 is a powder coating device with one below with reference to the 5a and 5b to be explained coater 52 which is in the process room 4 guided in the horizontal direction back and forth to move over the build platform 10 To deposit powder and thus to prepare a powder layer of predetermined thickness. In 2 he is in his rear parking position, in which he needs from the Pulvernachfülleinrichtung 12 can be charged with powder.

For the site-selective remelting of the powder in the respective last-prepared powder layer, a fiber laser (not shown) is used as the energy source, said fiber laser being applied via an in-fiber laser 3 indicated light guide 56 with the optics attachment 6 connected is. The optics attachment 6 has in his case 60 a motor-controllable beam expansion optics 62 for optional widening of the means of the optical fiber 56 at 64 in the optics essay 6 coupled laser light. The the beam expansion optics 62 leaving and in the 2 . 3 at 66 indicated laser beam hits a scanner assembly 70 in the case 60 of the optics tower 6 , The scanner arrangement 70 is controllable by means of a control computer (not shown) to the laser beam 66 targeted down through a provided with a protective glass F-theta lens (at 72 ) in a bottom opening of the plate 32 through to the construction platform 10 or to divert to a respective powder layer prepared thereon, in such a way that the laser beam 66 reaches the places intended for remelting the powder layer.

Out 4 it can be seen that the lower box part 14 of the process chamber housing 2 over the rear wall 30 also protrudes to the rear. In the rear projecting area 74 can the coater module 52 occupy its rear parking position while a respective powder layer on the build platform 10 is irradiated by laser radiation. If necessary, in the already indicated manner then powder from the Pulvernachfülleinrichtung 12 in the parker located in the coater module 52 from above through an opening in the rear attachment plate 24 can be initiated through. The powder replenishment device 12 has in the example case a powder tank 78 on, which at its lower end a funnel section 80 which has a lock and fill shaft powder through the opening (not shown) in the lower box lid plate 24 through to the coater module 52 can deliver.

At an upper filler neck 84 with a sliding shutter 86 is a refill bottle 90 connectable, from the new powder into the tank 78 can be introduced. The coater 52 is dimensioned so that it can accommodate sufficient for a large number of powder layers to be prepared supply of powder, so that a refueling of powder from the main container 78 is rarely required, eg only after the preparation of 100 powder layers. The coater 52 contains powder level sensors 92 . 94 whose signals are monitored by an electronic controller (not shown) of the rapid prototyping device. Refueling the coater 52 can then be done automatically. As soon as the intended for the monitoring of a minimum level level sensor 92 emits a signal indicating the undershooting of the minimum level, the electronic control device ensures that the coater 52 eg fueled with powder at the next stop in the parking position. This drives the in 4 recognizable dosing shaft motor 96 the example Schaufelradartig shaped and housed in a housing metering 82 to turn on, making the shaft powder out of the main tank 78 through the otherwise sealed to the outside opening in the cover plate 24 through into the upper filling opening 98 of the coater 52 promotes. As soon as the responsible for monitoring the maximum level powder sensor 94 detects the reaching of a predetermined maximum level and emits a relevant message signal to the electronic control device, the latter ensures that the powder replenishment from the main tank 78 is stopped by the dosing shaft motor 96 is stopped by the controller. There are other controllable closure mechanisms for the reservoir within the scope of the invention 78 conceivable.

After this automatic filling of the coater 52 This can again from his rear parking position on the construction platform 10 be moved forward to prepare a layer of powder on the build platform. For this purpose, the electronic control device controls the linear drive device 100 so that the coater 52 sets in motion. If necessary it should be provided that the coater 52 for the preparation of a powder layer in each case once over the build platform 10 is moved forward and back again. In principle, it may be enough if the coater 52 for preparation of a powder layer only once over the build platform 10 passes away, after which then the location-selective remelting of the powder by means of laser radiation takes place. Then the coater can 52 after reversing the direction again over the construction platform 10 drive away to lay down the next layer of powder.

How out 5b can be seen, the coater points 52 at its lower end a Pulverausgabespalt 102 on whose gap length in the example substantially the width of the build platform 10 equivalent. From this output gap 102 can the powder in a buffer space 104 of the coater 52 follow, this buffer space 104 is open at the bottom. The longitudinal edges of the lower buffer space opening are by Pulverabstreifabschnitte 106 . 108 formed, which in each case to be prepared powder layer during the movement of the coater 52 level and smooth. The scraping sections 106 and 108 are by side bars 110 connected to each other, so that the buffer space outlet opening is circumferentially framed. Preferably, the sections are located 106 . 108 . 110 in a common horizontal plane when sweeping over the build platform 10 , This peripheral frame of the buffer space outlet opening has the advantage that the powder when preparing a layer on the build platform 10 and not to a significant extent laterally across the direction of travel from the coater 52 can escape. The coater is thus virtually self-dosing, if he when passing the build platform powder from the buffer space 104 downwards.

Preferably, the lower frame sections 106 . 108 . 110 Components of an integrally connected smoothing slide ring 105 ,

The smoothing slide ring 105 is preferably such that, when leveling and leveling the material powder, it can deflect locally fixed obstacles in a zone-wise yielding manner. Such local obstacles may be, for example, elevations on remelted areas of the last irradiated layer. As material for the smoothing slide ring 105 come - not exclusively, but preferably - plastic materials in question. Thus, in particular silicone is suitable as a material for the smoothing slide ring 105 , The smoothing slide ring 105 may in particular have a circumferential silicone lip.

The width of the buffer space opening between the webs 110 of the coater 52 is essentially the width of the build platform 10 , so that in the layer preparation as possible no or at most little powder laterally across the direction of travel of the coater 52 on the bottom plate 16 of the process chamber housing 2 is filed. Preferably, the coater 52 so dimensioned that he is the build platform 10 can sweep across in full width, with the webs 110 the scraper ring 105 the coater the bottom plate 16 of the process chamber housing 2 touch.

At the beginning of the production of a shaped body, the electronic control device ensures by controlling the elevator drive 46 for being the build platform 10 in an upper position, in which the horizontal upper shelf of the building platform 10 by the extent of the powder layer to be subsequently prepared with respect to the horizontal upper surface of the bottom plate 16 is lowered. Thereafter, the electronic control device controls the linear drive device 100 of the coater 52 on the filled coater out of its rear parking position towards the front of the process room 4 to move. This gives the coater 52 Powder down on the build platform 10 out, with the scraper ring 105 of the coater 52 ensures the exact leveling and smoothing of the generated layer. After preparation of this first powder layer, the electronic control device then controls the scanner arrangement 70 in accordance with geometric data of the shaped body to be produced, so that of the scanner mirror elements 70 down through the F-theta lens 72 through deflected laser beam 66 Areas of the powder layer on the build platform 10 irradiated, which are to be by remelting coherently solidified areas of the lowest layer of the shaped body to be produced. After the irradiation step, the lowering of the construction platform takes place 10 by the measure of the thickness of the subsequently to be prepared powder layer. The coater 52 is then set in motion again to the build platform 10 to paint over and lay down a layer of powder. After the preparation of this second powder layer, an irradiation step corresponding to the cross section of the molded article to be produced in the second layer then takes place again. The steps of the layer preparation and the irradiation further alternate each other until the molded body to be produced is constructed. This is the construction platform 10 Step by step further into the hollow base (construction cylinder) 42 lowered.

The Creation of a molded body is preferably carried out in a protective gas atmosphere. As protective gas is e.g. Argon in question.

Preferably, at least one oxygen sensor is provided for monitoring the oxygen content in the process space. This oxygen In particular, the sensor serves to monitor the wash result when the process space is purged with the protective gas.

The device according to the invention has in particular the following advantages. Due to the possibility of access to the process space from the side after opening the swing gate 34 It is easier than previously possible to remove finished molded articles from the process space, for example by means of a forklift vehicle or the like. When removing the molded body remains the optical attachment 6 completely unaffected, so that a visual misalignment does not take place. In this regard, the invention thus has significant advantages over the previously known rapid prototyping devices, in which the access to the process space was only possible from above.

One Another advantage of the illustrated embodiment of the invention lies in that the main components are easy to assemble.

In this context, it should be noted that the plug side wall elements 26 . 28 . 30 and the front door 34 can be replaced by corresponding higher elements to the distance between the optical attachment 6 and the layer to be irradiated on the build platform 10 if necessary to increase, such as when the F-theta lens 72 to be exchanged for a lens with a different focal length.

Of the Process space can be made comparatively high.

In 2 is in the bottom plate 32 of the optics tower 6 a window is provided, which includes a process space observation by means of a in the optical attachment 6 provided (not shown) camera, eg web camera allows.

As 1 reveals, also identifies the front door 34 Viewing window on.

Thereon It should also be noted that the building platform by means of a heater e.g. can be electrically heated to the powder to be irradiated preheat.

The housing walls of the process chamber housing 2 and the optics tower 6 For example, they may be made of aluminum or another metal.

According to 2 can a gap 110 in the bottom plate 16 be provided, wherein at this gap a (not shown) powder collecting container is connected, which may possibly absorb excess powder. There is also the possibility of the coater 52 if necessary, through the gap 110 through to empty.

Furthermore, the following modifications are possible. Instead of Spindeltriebelevators 8th For example, a hydraulic elevator with, for example, at least one hydraulic piston-cylinder unit can be provided as a lifting drive for the construction platform. The point of view of the hydraulic elevator is of independent importance. Also of independent importance is the possibility of powder tracking from an external powder storage tank by means of a suction conveyor or vacuum conveyor. This can eg powder in the main tank 78 promote.

Claims (22)

Apparatus for producing a shaped body by layering of powdery, in particular metallic or ceramic material, with a process space housing ( 2 ), a carrier ( 10 ) for the layer structure, an irradiation device ( 6 ) for irradiating the respectively last on the support prepared material powder layer in one of these layer associated cross-sectional area of the model of the molded body with a radiation, in particular focused laser radiation, which brings the material powder in this cross-sectional area by heating for fusing or possibly for sintering, and a coating device ( 52 . 100 ) for the preparation of the respective following material powder layer on the last irradiated layer, wherein the coating device ( 52 . 100 ) a combined powder dispensing and layer smoothing device ( 52 ), characterized in that the process space housing has a side door ( 34 ), after the opening of the process space is accessible from the respective side in the horizontal direction. Device for the production of a shaped body according to claim 1, characterized in that the process space housing at the top of an optical attachment ( 6 ), which comprises the irradiation device in a housing. Device for the production of a shaped body according to claim 2, characterized in that in the bottom of the optical attachment ( 6 ) and the ceiling of the process chamber housing ( 2 ) forming wall ( 32 ) a window for the passage of the radiation is provided, wherein in this window an f-theta lens ( 72 ) is provided with process space side protective cover. Device for the production of a shaped body according to claim 3, characterized in that the window centrally above the support ( 10 ) for the layer structure is located. Device for producing a shaped article according to one of the preceding claims, characterized in that the radiation is a laser beam which is generated by means of a controllable scanner arrangement ( 70 ) in the optical attachment ( 6 ) controlled to the carrier ( 10 ) is selectively distractable. Device for producing a molded article according to Claim 5, characterized in that as a laser, a fiber laser is provided. Apparatus for producing a shaped article according to claim 6, characterized in that the fiber laser outside the optical attachment ( 6 ) is provided and by means of an optical fiber with the optical attachment ( 6 ) is optically connected. Device for producing a shaped article according to one of the preceding claims, characterized in that the optical attachment ( 6 ) contains a controllable Strahlaufweitelement. Device for producing a shaped article according to one of the preceding claims, characterized in that the optical attachment ( 6 ) as a structural unit on the process space housing ( 2 ) can be plugged. Device for producing a shaped article according to one of the preceding claims, characterized in that the process chamber housing ( 2 ), if necessary, operationally replaceable side wall elements ( 26 . 28 . 30 ) having. Device for producing a shaped article according to claim 10, characterized in that the exchangeable side wall elements ( 26 . 28 . 30 ) on a lower box part ( 14 ) of the process chamber housing ( 2 ), in particular fixed by plug connections. Device for producing a shaped article according to claim 11, characterized in that the lower box part ( 14 ) of the process chamber housing ( 2 ) a bottom plate ( 16 ) with a through hole ( 40 ), through which the carrier ( 10 ) is to be coated with powder. Device for the production of a shaped article according to claim 12, characterized in that the carrier ( 10 ) in one the bottom plate ( 16 ) of the process chamber housing ( 2 ) supporting hollow socket ( 42 ) vertically by means of a particular a spindle drive ( 44 . 46 ) elevator device ( 44 . 46 . 50 ) is adjustable. Device for producing a shaped article according to claim 13, characterized in that the elevator drive ( 44 . 46 . 50 ) Means for measuring the respective vertical position of the carrier ( 10 ). Apparatus for producing a shaped body by layered build-up of pulverulent, in particular metallic or ceramic material, with a support for the layer structure, an irradiation device for irradiating the last of the material powder layer prepared on the carrier in a cross-sectional area of the model of the shaped body with radiation assigned to this layer, In particular, focused laser radiation, which brings the material powder in this cross-sectional area by heating for fusing or possibly for sintering, a coating device for preparing the respective subsequent powder layer on the last irradiated layer, wherein the coating device at least a distance of the desired powder layer thickness over the last irradiated layer removable coater ( 52 ) comprises a Pulverabgabe- and layer smoothing device, in particular according to one of the preceding claims, characterized in that the coater can accommodate a storage volume of powder, which is sufficient for the preparation of a plurality of powder layers of predetermined thickness. Apparatus for producing a shaped body by layered build-up of pulverulent, in particular metallic or ceramic material, with a support for the layer structure, an irradiation device for irradiating the last of the material powder layer prepared on the carrier in a cross-sectional area of the model of the shaped body with radiation assigned to this layer, In particular, focused laser radiation, which brings the material powder in this cross-sectional area by heating for fusing or possibly for sintering, a coating device for preparing the respective subsequent powder layer on the last irradiated layer, wherein the coating device at least a distance of the desired powder layer thickness over the last irradiated layer removable coater ( 52 ) comprising a powder dispensing and layer smoothing device, in particular according to claim 15, characterized in that the powder dispensing and layer smoothing device has a lower powder dispensing opening, which circulating from a smoothing slide ring ( 105 ) is limited. Device for producing a shaped article according to claim 16, characterized in that the smoothing slide ring ( 105 ) made of plastic, in particular made of silicone. Device for producing a shaped article according to one of Claims 15-17, characterized in that the coater ( 52 ) has at least one powder level sensor. Device for producing a shaped article according to one of Claims 15-18, characterized in that the coater ( 52 ) is automatically filled with powder from an external powder source in a predetermined parking position within the process chamber housing. Apparatus for the production of a shaped article according to any one of claims 15-19, characterized in that the coater is dimensioned such that it during its guided back and forth movement the full width of the carrier ( 10 ) transverse to the direction of travel of the coater ( 52 ) and sweeps at its lower end a base plate ( 16 ) of the process chamber housing. Device for the production of a shaped article according to one of the preceding claims, characterized in that the carrier in a structural cylinder below a bottom plate ( 16 ) of the process chamber housing ( 2 ) is vertically adjustable. Device for producing a shaped article according to one of the preceding claims, characterized in that a powder reservoir ( 78 ) on the outside of the process space housing ( 2 ) is arranged, and by means of a powder conveyor ( 82 . 96 ) Powder through a housing opening of the process chamber housing into the in a predetermined parking position coater ( 52 ).