WO2008116627A1

WO2008116627A1 - Device for producing objects

Info

Publication number: WO2008116627A1
Application number: PCT/EP2008/002352
Authority: WO
Inventors: Matthias Fockele
Original assignee: Matthias Fockele
Priority date: 2007-03-28
Filing date: 2008-03-25
Publication date: 2008-10-02
Also published as: DE102007014968A1

Abstract

The present invention relates to a device for producing objects (29) by the layered structuring of powdery, particularly metal and/or ceramic materials, comprising a carrier arrangement having a carrier (28) and a construction cylinder (18) surrounding the carrier (28), which together form a construction space (24) for the layered composition, and a radiation device (20) for applying radiation to the respectively last material powder layer prepared on the carrier arrangement in a cross-sectional region of the object (29) in question, or optionally the objects in questions, associated with said layer, using radiation, particularly laser radiation, which causes the material powder in said cross-sectional region to melt, or optionally to sinter, by heating, wherein the radiation device has a controllable target device for the radiation to apply the radiation to select points of the construction field. According to the invention, the construction cylinder (18) is vertically movable in relation to the carrier (28) in order to be able to form a construction space (24) having a greater height as the number of layers increases.

Description

Device for the production of articles

description

The present invention relates to a device for producing objects by layering of powdered, in particular metallic and / or ceramic material, wherein it comprises a support assembly with a support and a surrounding the support cylinder, which together form a space for the layer structure, and wherein they further comprise an irradiation device for irradiating the respective last-on the carrier assembly prepared material powder layer in a layer associated cross-sectional area of the subject or optionally the objects in question with radiation, in particular laser radiation, the material powder in this cross-sectional area by heating for fusing or possibly for sintering brings, wherein the irradiation device has a controllable target device for the radiation for the location-selective irradiation of the construction field.

The invention relates in particular to the field of selective laser melting and is based on a technology as described, for example, in WO 2006/024373 A2 or DE 10 2005 014 483 A1, the invention also being applicable to the field of laser sintering ,

According to DE 10 2005 014 483 A1, selective laser melting has hitherto been mainly used for the production of filigree or intricately shaped small parts in individual production. This is due to the fact that the construction field on the support for the layer construction was limited to a relatively small construction field surface, on the one hand, because the irradiation device only a narrowly limited area with the required beam quality and, on the other hand, because the production of larger articles by the selective laser melting method also requires the handling of correspondingly large amounts of material powder, thereby loading the carrier platform with very great weight. The fine gradation in the known vertical movement of the support platform for adjusting the correct working distance between the layer surface and the irradiation device thus becomes more difficult as the weight of the material powder on the support platform increases.

The object of the invention is to provide a device of the type mentioned, which allows the production of larger items or possibly a larger number of items.

To achieve this object, the invention proposes that the structural cylinder is vertically movable with respect to the carrier in order to be able to form an installation space of greater height with increasing number of layers.

Since the vertically adjustable construction cylinder has a substantially constant weight, the vertically acting forces to be taken into account in the case of a vertical movement also remain substantially the same regardless of the layer thickness. Optionally, slightly increased frictional forces are to be overcome with increasing layer thickness, which act between the inside of the construction cylinder and the material powder. The support, which must support the entire weight of the material powder, can thus be firmly supported, at least during the manufacture of an article, on a base frame of the device which is standing on the ground. Since the carrier can usually be heated, this has the further advantage that supply lines, in particular for the integrated heating, for temperature sensors and the like need not be moved.

According to a preferred embodiment, the irradiation device in particular synchronously with the structural cylinder vertically movable, so that the distance between the irradiation device, in particular the target device, and a respectively to be irradiated material powder layer remains substantially similar. If the distance between the irradiation unit and the material powder layer to be irradiated is variably adjustable, the size of the point of the beam impinging on the material powder layer can thus also be influenced by a slight change in the focal position.

If a synchronous movement is required, it is particularly advantageous if the structural cylinder and the irradiation device are interconnected by a frame construction, so that a fixed vertical distance is maintained between them, which is maintained by changing the vertical height of the construction cylinder by the simultaneous vertical displacement of the irradiation device becomes.

In order to effect the vertical movement of the construction cylinder, it is proposed that the device comprises at least one lifting device. In this context, it should be noted that it is conceivable as an alternative to the above-mentioned frame construction between the construction cylinder and irradiation device that the building cylinder and the irradiation device are each adjustable in their vertical height via separate lifting devices, so that possibly also a different distance between the irradiation device and the construction cylinder is adjustable.

The lifting device, which is preferably controlled via a control device, so that the construction cylinder is adjustable in height according to the desired thickness of a respective material powder layer to be applied, is preferably designed as a hydraulic or mechanical actuator. Such an actuator should be gradually adjustable according to the desired thickness of a respective material powder layer to be applied, in particular by a few micrometers per layer, which requires precise control. Such Precision of the control is advantageously supported by the fact that with the Stellanatrieb only the building cylinder and possibly the irradiation device must be adjusted vertically or must, whose or their weight is constant, so that the design of the actuator can be selected accordingly.

In order to be able to apply a respective material powder layer on the last irradiated material powder layer, it is proposed that the device has a device for preparing a respective material powder layer on the last-irradiated material powder layer, this layer preparation device having a smoothing slide movable away from the last irradiated layer at a distance of the desired powder layer thickness for leveling a respective amount of material powder over the last irradiated layer.

It is particularly preferred that the

Layer preparation device, in particular synchronously with the building cylinder is vertically movable, in particular, it is thought that the layer preparation device is disposed in a vertically upper edge region of the building cylinder and its smoothing slide is movable relative to the building cylinder in the horizontal direction.

It is particularly preferred that the smoothing slide is movable in the horizontal direction over the edge of the building cylinder in order to remove excess material powder from the installation space into a collecting container. The pushed over the edge of the building cylinder away powder material preferably falls in adjacent to the building cylinder along extending shafts that open into the collection. Alternatively, it is also conceivable that the smoothing slide is movable within the building cylinder, which of course makes appropriate redesigns on the structural cylinder necessary to be able to supply excess material powder to the collecting container can. So that the space of material powder can be cleaned, it is proposed that the device a

Material powder removal device, with, in particular after completion of the article, excess material powder is one or the collecting container can be fed. Here, for example, a subsequent at the bottom of the cylinder hopper can be provided, which makes it possible to raise the building cylinder after completion of the object so that between the lower edge of the building cylinder and the support, a gap is formed, the transition between the space and the Funnel forms, so that excess material powder falls by gravity from the space in the subsequent funnel below. Further, a vacuum pump or the like may be provided, which removes material powder from the space by supplying a negative pressure and supplies the collecting container. Alternatively, of course, a compressor device is conceivable for blowing out the material powder from the installation space.

In order to further simplify the complete removal of material powder, it is proposed that the support is rotatable and / or pivotable and / or vibratory mounted. Such storage makes it possible, for example, after removal of the finished article, to pivot the carrier about a horizontally extending central axis, so that excess material powder trickles along the inclined surface of the carrier in the direction of the collecting container. A similar effect can be achieved by a vibration of the carrier, in which, if necessary, adhering to the support surface powder residues of this dissolve and can be removed in the sump.

In order to prevent oxidation effects on the material powder, it is further preferred that the device has a housing which limits a process chamber containing the structural cylinder for the layered production of one or more objects, and a device for Production and maintenance of a protective gas atmosphere, in particular argon protective gas atmosphere, in the process space.

In order to remove a finished object from the installation space, on the one hand, the removal of the excess material powder, the construction cylinder can be moved vertically downwards, so that access to the finished, lying on the support workpiece is possible. On the other hand, it is also conceivable to provide in the construction cylinder at least one closable opening which can be opened for removal of the finished article when the construction cylinder is extended. Furthermore, such a closable opening is also advantageous in order, after a coarse removal of the main part of material powder by the removal device, to be able to carry out manual cleaning of the workpiece and / or installation space with brushes, brushes or the like. Of course, in this case, the housing of the device should be designed such that manual work in the space or process space can be performed under a protective gas atmosphere, possibly using a lock chamber or the like., As is known from WO 2006/024373.

Of course, it is also conceivable to combine the vertical adjustment of the construction cylinder with a vertical Versteilbarkeit of the carrier, so that a device is formed in which either selectively and depending on the object to be manufactured, the carrier vertically down or the building cylinder is moved vertically upwards to a to prepare next material powder layer. Optionally, such a vertical mobility of the carrier and the construction cylinder could be carried out by the same lifting device, it may be advantageous to provide an additional, independent of the lifting support for the carrier with vertical adjustability of the cylinder, in order to produce a larger object or multiple objects to optimally support the large weight acting on the carrier and the risk of unwanted vertical movement of the wearer submissions.

The invention will now be described by way of example and not limitation with reference to two embodiments with reference to the accompanying drawings.

Fig. 1 is a schematic perspective view obliquely from above of a first embodiment of the device according to the invention with retracted building cylinder at the beginning of the manufacture of an article.

Fig. 2 is a schematic perspective view of the apparatus of FIG. 1 with the boom extended.

FIG. 3 is a schematic partial sectional view of the apparatus of FIG

Fig.1 according to the line IM-III.

4 is a schematic partial sectional view along the line IV-IV of FIG. 2.

Fig. 5 is a similar to Fig. 4, a schematic partial sectional view, wherein in addition a Hubvorrichtungsanordnung for the building cylinder is shown.

Fig. 6 is a similar to Fig. 4, a schematic partial sectional view of a second embodiment.

As shown in FIG. 1, a device 10 for the production of articles by layering of powdered material has a base frame 12, a collecting container 14, a base plate 16, a construction cylinder 18, and an irradiation device 20, which are surrounded by an outer housing, not shown. The building cylinder 18 and the irradiation device 20 are two carriers 22, which a Spacer frames form interconnected. Further, the base frame 12 and the base plate are connected to each other via a structure 13 indicated only in Fig. 4.

As is apparent from Fig. 2, the structural cylinder 18, the carrier 22 and the irradiation device 20 are vertically upwardly displaced relative to the base plate 16, which corresponds for example to a state after completion of the article to be manufactured. The finished object and the remaining unmelted material powder are in the construction space 24, which is formed by the walls 26 of the construction cylinder 18 and a support 28 (FIG. 3), the finished object resting on the support 28.

As can be seen from the partial sections of FIGS. 3 to 6, which are shown above a break line B, the construction cylinder 18 is at a lowermost position (FIG. 3) at the beginning of production of an article, its vertical walls 26 extending into the region of the collecting container 14 , Two of the walls 26 of the construction cylinder 18 have an opening 30 extending along these walls, through which excess material powder can be removed from the installation space 24 and supplied to the lower-lying collection container 14 when a new material powder layer is prepared by means of a sliding slide 23.

The irradiation device 20 has four f-theta lenses 32 in the present embodiment. This allows, in particular, the quasi-simultaneous processing of four construction areas, for example for the production of four objects or for the treatment of a multiple construction claims claiming object. With regard to the further technical features of the irradiation device 20, reference is made to the above-mentioned publications.

In the manufacture of an article by layering of powdery material is in the present embodiment, starting from a state shown in FIG. 3 of the building cylinder 18 by means of a lifting device 34 shown schematically in Fig. 5 by the amount of thickness of a first layer of material powder moved by a few microns vertically upwards. The lifting device 34 is shown schematically as a spindle drive, which can be rotated by a motor 36 fixed to the base frame 12 in rotation. The spindle rods 35 act on horizontal projections 37 of the construction cylinder 18 so that they can lift and lower this vertically. Preferably, four drives are provided, which are controlled synchronously by a control unit, not shown, of the device. Thus, the spindle rods 34 can be extended, the base plate 16 has two, relative to the image plane of Fig. 3-5 left and right of the building cylinder arranged longitudinal slots 38 through which the spindle rods 35 are passed.

After application of a first material powder layer by the smoothing slide 23, which can also be a combined powder dispenser / smoothing slide, for example, a first fusion of powder takes place by means of the irradiation device 20. Subsequently, the construction cylinder 18 is again moved vertically upward by the thickness of a next material powder layer to be applied, so that with the powder dispenser / smoothing slide 23, a further material powder layer can be prepared. The smoothing slide 23 is thereby moved horizontally along the upper edge of the construction cylinder 18, wherein it is movable beyond its inner walls 26, so that excess material powder can be removed into the shafts 30 by the smoothing slide. This layer-wise application of material powder and subsequent fusion while simultaneously raising the vertical cylinder 18 and thus increasing the space 24 to a maximum height required, is continued until the desired workpiece or the desired workpieces is completed or are. The device is then in a state according to FIG. 5, wherein the article to be produced 29 rests on the surface of the carrier 28 and around it in the space 24 unmelted material powder 31 is present. In order to be able to remove the object 29 from the device, the remaining, unmelted material powder 31 must be removed from the installation space 24 again.

For this purpose, a removal device shown in Fig. 4 is used, which has a sleeve or a funnel 40, which can be pushed vertically over this in the lower region of the building cylinder 18. The hopper 40 is supported by means of springs 41 on the base plate so that it automatically moves up when the boom up when the projections 37 do not press him down, as in the starting position of FIG. 3 is the case. The funnel walls 42 and the outer sides of the construction cylinder walls 26 thus overlap in a certain vertical range, so that it is possible to move the construction cylinder so far relative to the hopper 40 vertically upward until between the Bauzylinderwänden 26 and the carrier 28, a gap 44th is formed, trickle through the material powder into the hopper 40 and then the collecting container 14 or can be sucked by means of a corresponding vacuum device.

According to a second embodiment of the present invention, which is shown in FIG. 6, outer walls 27 of the construction cylinder 18 are extended downwardly, so that they allow a sealing of the installation space to the outside, even if the inner walls 26 are raised so far, the gap 44 is formed between them and the carrier 28. The excess material powder 31 can thus be guided through the gap 44 and along the extended outer walls 27 down into the collecting container 14. In this second embodiment can be dispensed with the spring-loaded sleeve 40 of the first embodiment, which has a simplified construction result. The outer walls 27 can be extended on all four sides of the construction cylinder 18 be formed, so that there is a double-walled construction cylinder 18 on all sides. Such a construction allows the material powder on all four sides of the carrier 28 by the circumferential gap 44 can fall away downwards. Alternatively, it is also conceivable to form only the two outer walls 27 extended, which form the two shafts 30 with the inner wall 26. The reference to the plane to the shafts 30 front and rear extending inner walls 26 would then also have to be extended downwards, so that they still rest on the carrier 28 when the gap 44 is opened with respect to the plane of the left and right.

The support 28, on which the total weight of the material powder located in the installation space is loaded, is supported on the base frame 12 via a corresponding construction, for example by supports 13 or the like, so that it is stationary at least during production of the object. However, it is conceivable that the support 28 is to some extent movable, in particular rotatable, pivotable or vibratory, to assist in the removal of residual material powder.

The construction cylinder 18 may possibly have in one of its walls 26, which preferably has no shaft 30, a closable opening through which access to the installation space 24 is possible with the construction cylinder 18 extended. However, such an opening can also be provided in a double-walled construction cylinder design. Through the opening, after completion of the construction process z. B. the finished object are removed. The collecting container has at its lower end to a screw conveyor 43 which supplies the collected material powder to a transport container or possibly a recycling device.

Finally, it should also be pointed out that the application of layers of material powder and the fusion takes place in a process space, not shown here, which is under a protective gas atmosphere, in particular argon protective gas atmosphere, is, as is known from the above-mentioned documents. Of course, corresponding lock devices can also be provided in the device presented here in order to enable a transition between the process chamber under a protective gas atmosphere and the outside world.

Claims

claims

1. A device for the production of articles (29) by layering of powdered, in particular metallic and / or ceramic material, comprising: a carrier assembly with a carrier (28) and a support (28) surrounding the structural cylinder (18), which together Forming space (24) for the layer structure, and an irradiation device (20) for irradiating each of the last on the support assembly prepared powder layer in a layer associated cross-sectional area of the subject (29) or possibly the relevant objects with radiation, in particular laser radiation, the the material powder in this cross-sectional area by heating for

Melting or possibly sintering brings, wherein the irradiation device (20) has a controllable target device for the radiation for the location-selective irradiation of the construction field, characterized in that the construction cylinder (18) with respect to the support (28) is vertically movable to increase with increasing number of layers to be able to form a construction space (24) of greater height.

2. Apparatus according to claim 1, characterized in that the irradiation device (20) in particular synchronously with the

Construction cylinder (18) is vertically movable, such that the distance between the irradiation device (20), in particular the target device, and a respectively to be irradiated material powder layer remains substantially similar.

3. Apparatus according to claim 2, characterized in that the construction cylinder (18) and the irradiation device (20) by a frame structure (22) are interconnected.

4. Device according to one of the preceding claims, characterized in that it comprises at least one lifting device (34, 35, 36), which causes the vertical movement of the building cylinder (18).

5. The device according to claim 4, characterized in that it comprises a control unit, which controls the lifting device (34, 35, 36) such that the construction cylinder (18) is adjustable in height according to the desired thickness of a respective material powder layer to be applied.

6. Apparatus according to claim 4 or 5, characterized in that the lifting device is designed as a hydraulic and / or mechanical actuator (34, 35, 36).

7. Device according to one of the preceding claims, characterized in that it comprises means (23) for preparing a respective material powder layer on the last irradiated material powder layer, wherein these

Layer preparation device has a spaced apart the desired powder layer thickness over the last irradiated layer away movable smoothing slider for leveling a respective amount of powder material over the last irradiated layer.

8. The device according to claim 7, characterized in that the layer preparation device (23) in particular in synchronism with the structural cylinder (18) is vertically movable.

9. Apparatus according to claim 8, characterized in that the layer preparation device (23) is arranged in a vertically upper edge region of the construction cylinder (18) and her Smoothing slider is movable relative to the building cylinder in the horizontal direction.

10. The device according to claim 9, characterized in that the smoothing slide in the horizontal direction over the edge of the

Construction cylinder (18) is movable to excess

Remove material powder from the installation space in a collecting container (14).

11. Device according to one of the preceding claims, characterized in that it comprises a material powder removal device (40), with, in particular after completion of the article, excess material pu I ver one or the collecting container (14) can be fed.

12. Device according to one of the preceding claims, characterized in that the carrier (28) is mounted rotatably and / or pivotally and / or vibratable.

13. Device according to one of the preceding claims, characterized in that it defines a housing which defines a process chamber containing the structural cylinder (18) for the layered production of one or more articles, and a device for producing and maintaining a protective gas atmosphere, in particular argon protective gas atmosphere , in which process room has.