DE102016213420A1 - Method and device for the generative production of a component - Google Patents

Abstract

The invention relates to a method for the generative production of a component (1), in which a beam (2) generated by a radiation source (10) is directed onto a material (5) forming the component (1) and the material (5) is selectively melted , whereupon the molten material (5) solidifies after melting to form the component (1). According to the invention, it is provided that the beam (2) is passed through a beam-shaping element (20) arranged in the beam path.

Description

State of the art

The invention relates to a method for the generative production of a component according to the preamble of claim 1. Furthermore, the invention relates to a device for carrying out the method according to the invention.

From the EP 2 878 402 A1 a method according to the preamble of claim 1 is known. In the known method, a beam generated by an electromagnetic radiation source, in particular a laser beam device, is directed by means of an optical device onto a particularly powdery material which is melted by the beam. After solidification of the material and removal of the surrounding material, which has not been melted, is generated by the solidified material, the component to be formed. Such a method has also become known in practice as a "3D prototyping" method. The known method is thus characterized by a spatially selective melting and subsequent solidification of material. It is important to allow a locally precise and defined in its effect melting of the material in order to comply with the desired geometry or properties of the component to be manufactured. For this purpose, the known method has a deflection device in the beam path of the beam with which a partial beam of the beam directed in the direction of the material is decoupled. The decoupled beam is used in particular for detecting the power of the beam and can be used as a control variable for the processing device.

The selective melting of the material requires that in the region of the component to be produced the material can be melted at any desired spatial point. For this purpose, it is necessary, for example, to provide a relative movement between the jet and the material to be melted or vice versa. Usually, the beam has a round cross section in the focal point. Furthermore, the melting of the material takes place only in a single spatial point or region and the laser beam always has the same shape or the same cross section in the focal point during the process.

Disclosure of the invention

Based on the illustrated prior art, the invention has the object, a method for the generative production of a component according to the preamble of claim 1 such that a more effective production of the component is made possible, and that at the same time or alternatively the component has improved properties. In the context of the invention, a more effective production means in particular the increase in the build-up rate of material of the component and thus a faster production of the component. Among improved properties of a device produced by a process are exemplary, and not limiting, the reduction of residual stresses and distortions in the produced component, a reduction of surface roughness, a reduction of micro-defects (pores, hot cracks, stress cracks), an improvement of the microstructure and the Component properties (stiffness, strength, etc.) as well as an improvement or expansion of the materials to be machined (eg poorly weldable materials) understood.

This object is achieved in a method for the generative production of a component having the features of claim 1.

The invention is based on the idea of guiding the beam through a beam-shaping element arranged in the beam path. In the context of the invention, a beam-shaping element is understood by way of example and not by limitation to mean a LCOS (Liquid Crystal on Silicon) SLM element, an adaptive mirror a micromirror array. A Spatial Light Modulator (SLM) is a spatial modulator for electromagnetic radiation, in particular light, which imposes a spatial modulation, in particular intensity modulation, on a beam. It is thus essential for the beam-shaping element that this enables a power density distribution in a working plane of the beam. The working plane here is a plane that intersects the beam. Preferably, the working plane is arranged substantially perpendicular to the propagation direction of the beam. The working plane is further distinguished by the fact that in the working plane, the melting of the material for the production of the component takes place. In this case, the power density denotes the power of the beam with respect to a surface unit, while the power density distribution designates the location-dependent power density present in one surface, in particular the working plane. When using an SLM (Spatial Light Modulator) element, the advantage is achieved, for example, that the beam can be divided by the SLM element, for example, into a plurality of partial beams. In addition, an SLM element makes it possible to shape the beam so that a defined distribution of the beam intensity of the beam in the space is made possible. The use of such an SLM element thus makes it fundamentally possible, on account of its properties for influencing the jet, to fulfill the abovementioned advantages individually or in combination.

Advantageous developments of the method according to the invention for the generative production of a component are listed in the subclaims.

When using a beam-shaping element which divides the beam into a plurality of partial beams and / or alters the beam in its cross-sectional shape, it is preferably provided that at least one beam, which is linear in cross-section, is generated. Such a method has the particular advantage that the build-up rate is increased and thus the time required for the production of the component can be reduced. This is achieved, in particular, by dividing the beam and thereby enabling parallelization, in which large-area processing of the material to be melted by the partial beams can be achieved.

Due to the flexible beam shaping, the position of the individual or partial beams can be adapted to one another to the geometry to be exposed. This allows the parallelization to be used more effectively. In particular, by the use of linear beam shapes, a substantial increase in the build-up rate can be achieved. A major advantage of such line-shaped beam shapes lies in the increase in the build-up rate without increasing the layer thickness, since in a certain level, a larger area of material can be melted simultaneously. However, the use of linear beam forms has the disadvantage that the scanning direction is no longer independent of the beam shape. However, this can be compensated by the flexible and dynamic beam shape. Furthermore, the width of the linear beam shape can be adapted to the geometry of the component to be produced.

In an alternative or additional embodiment, provision may be made for the area of the material surrounding the component to be heated at least in regions by the jet to a temperature below its melting temperature. Such a method leads to a reduction of residual stresses and distortion and to increase the rigidity and strength in the component to be produced. This can be explained by the fact that residual stress and distortion can be reduced by reducing temperature gradients. This is achieved by using the beam for the targeted setting of a temperature field. For example, pre-heating or post-heating can be achieved by large-area irradiation in front of or behind the actual molten bath. Furthermore, the temperature field can be adjusted by the targeted use of several partial beams. Also, both hot and stress cracks (cold cracks) can be reduced or avoided by adjusting the temperature field or the temperature gradient and thus the cooling rate.

A further advantageous embodiment of the method according to the invention provides that the material in the region which serves to form the component, steadily, i. is irradiated without relative movement between the beam and the material. Such a method has the particular advantage of reducing the surface roughness in the manufactured component. This is because the surface roughness is affected by the movement of the molten bath. Now, the flexible beam shaping by means of the beam-shaping element offers the possibility of simultaneously exposing the entire contour of the component to be produced or parts thereof, without moving the beam relative to the material. This leads to a reduction in the roughness of the component.

It can also be provided that a multiple remelting of the material takes place by the method. This also makes it possible to reduce the surface roughness of the manufactured component. In particular, the surface is significantly improved by multiple remelting of the same layer of the material. This is achieved by the flexible beam splitting, in which two or more beams travel one behind the other, wherein, depending on the scanning direction, the two beams are aligned with each other. Such a double exposure or a multiple remelting also makes it possible to realize a reduction of microdefects such as pores, hot cracks, stress cracks etc. on the component. It should be noted that the formation of pores in the production of the component is directly related to the surface quality of the individual layers. By the mentioned double exposure or the multiple remelting of the material, the tightness of the component can be significantly increased and thus the tendency to pore formation can be reduced.

In a further development of the proposal made last in the case of multiple remelting, it is proposed that the multiple remelting be effected by at least two partial beams which are arranged at a spatial distance from one another and which are moved relative to the material.

A further advantageous embodiment of the method provides that the beam is formed so that the temperature of the material in a direction extending in the direction of the beam is different, such that the material on the side on which the beam first impinges on the material , is lowest. Such a method makes it possible, in particular, to improve the microstructure and the component properties by virtue of the fact that, in addition to the local temperature field, the global temperature field affects the microstructure. In particular, the proposed method makes it possible to align the crystal growth on the component in the desired direction from the bottom up.

Finally, another preferred method proposes that the cross-sectional shape of the beam be changed during the irradiation of the material, whereby the processing can be optimally adapted to the component geometry.

The invention further comprises an apparatus for carrying out the method according to the invention described so far, wherein the radiation source is designed as a laser beam source and an arranged in the beam path of the laser beam SLM element is provided.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing.

This shows in:

1 a simplified representation of a device for the generative production of a component and

2 to 4 each views of a region of the material to be machined with incident on the surface of the material, differently shaped partial laser beams.

The same elements or elements with the same function are provided in the figures with the same reference numerals.

In the 1 is greatly simplified a device 100 for the generative production of a component 1 shown. The device 100 includes a radiation source 10 , in particular in the form of a laser beam source 11 , which is designed, for example, a laser beam 2 with a wavelength of 1064nm. The laser beam 2 is by means of one or more, not shown in detail, because known per se optical elements 12 machined and in the direction of the component to be produced 1 directed. In the beam path of the laser beam 2 is also a beam-shaping element in the form of an SLM element 20 (Spatial Light Modulator) arranged, which serves the laser beam 2 to shape or divide into several sub-beams.

The component 1 is made in particular powdery or granular material 5 produced within a trough-shaped container 6 is arranged, the height of which in the container 6 arranged material 5 at least the height of the component to be manufactured 1 equivalent. In the material 5 it may in particular be metallic material or plastic material.

It is essential, moreover, that the melting of the material 5 inside the container 1 a relative movement between the laser beam 2 with the material 5 in the direction of the three spatial axes X, Y and Z can be made possible. This is, as is known, either by a corresponding adjustment of the optical elements 12 or the SLM element 20 and / or but by an adjustment for the container 6 allows.

The production or production of the component 1 from the material 5 takes place in that the focus of the laser beam 2 so on the material 5 that is directed the material 5 is melted selectively layer by layer or point by point and that of the laser beam device 11 or the laser beam 2 opposite side of the surface 7 of the material 5 in the container 6 towards the surface 7 out. After melting the material 5 becomes the laser beam 2 in relation to the material 5 Moved so that the first molten material 5 solidifies and in the solidified area a component of the component 1 formed. The not frozen material 5 can after the manufacture of the component 1 from the interstices of the component 1 , as is known, be removed. In the 1 is greatly simplified the component 1 through elements 9 characterized during the impingement of the laser beam 2 caused by the fact that the material 5 first melted and then solidified.

In the 2 is a component contour 30 shown, which is exemplified in plan view rectangular. The contour 31 , which is also rectangular in shape, represents the inner contour of the container 6 in which the material 5 is arranged. Based on 2 is recognizable by the SLM element 20 for example, two partial beams 32 . 33 from the laser beam 2 are formed, each having a rectangular or linear contour. Exemplary are the two partial beams 32 . 33 arranged at a distance a from each other, wherein the width b of the partial beams 32 . 33 the width of the component to be produced 1 equivalent. Using the double arrow 34 it can be seen that the two partial beams 32 . 33 synchronously over the surface of the component to be formed 1 in the area of the contour 31 be moved back and forth.

In the 3 the case is shown in which within the component contour 30 also two partial beams 35 . 36 are generated, however, have a smaller width b than the component to be formed 1 , The training is thus carried out by line-like shutdown of the component contour 30 , Also the two partial beams 35 . 36 have an example of a distance a to each other and be according to the double arrow 34 over the surface of the material 5 within the component contour 30 emotional. Furthermore, by way of example, two further partial beams 37 . 38 with opposite to the partial beams 32 . 33 different cross section recognizable, which outside the component contour 30 but within the contour 31 are arranged. The exemplary likewise a rectangular contour having partial beams 37 . 38 serve to warm the material 5 in a component 1 near area, but outside of the material 5 that the component 1 formed. It is essential, moreover, that the performance of partial beams 37 and 38 such is that no melting of the material 5 he follows. The partial beams 37 and 38 serve together with the sub-beams 32 . 33 (the melting of the material 5 serve) for generating a temperature field or of temperature gradients.

Last is in the 4 exemplified by the case, in the three, each having a round cross-sectional shape having partial beams 41 to 43 generated within the component contour 30 a melting of the material 5 cause. The size or the diameter of the partial beams 41 to 43 as well as their exact position within the component contour 30 can be different.

The method described so far can be varied or modified in many ways, without departing from the spirit of the invention.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2878402 A1 [0002]

Claims (10)

Method for the generative production of a component ( 1 ), in which one of a radiation source ( 10 ) generated beam ( 2 ) on a component ( 1 ) forming material ( 5 ) and the material ( 5 ) is melted selectively, whereupon the molten material ( 5 ) after melting to form the component ( 1 ) solidified, characterized in that the jet ( 2 ) by a in the beam path of the beam ( 2 ) arranged beam-shaping element ( 20 ), in particular SLM element, an adaptive mirror or a micromirror array, for the power density distribution of the beam ( 2 ). A method according to claim 1, characterized in that the beam ( 2 ) by the beam-shaping element ( 20 ) in partial beams ( 32 . 33 ; 35 to 38 ; 41 to 43 ) and / or changed in its cross-sectional shape. A method according to claim 2, characterized in that a cross-sectionally line-shaped partial beam ( 32 . 33 ; 35 to 38 ) is produced. Method according to one of claims 1 to 3, characterized in that the component ( 1 ) surrounding area of the material ( 5 ) at least partially from the beam ( 2 ) or the partial beam ( 37 . 38 ) is heated to a temperature below its melting temperature. Method according to one of claims 1 to 4, characterized in that the material ( 5 ) in the area used to form the component ( 1 ) serves, steadily, ie without relative movement between the beam ( 2 ) or the partial beam ( 32 . 33 ; 35 to 38 ; 41 to 43 ) and the material ( 5 ) is irradiated. A method according to any one of claims 1 to 5, characterized in that the material ( 5 ) is remelted several times. A method according to claim 6, characterized in that the multiple remelting by at least two Teilstahlen ( 32 . 33 ; 35 . 36 ; 41 to 43 ), which are arranged at a spatial distance (a) from each other and which are relative to the material ( 5 ) are moved. Method according to one of claims 1 to 7, characterized in that the beam ( 2 ) or the partial beam ( 32 . 33 ; 35 . 36 ; 41 to 43 ) is formed so that the temperature of the material ( 5 ) in a direction of the beam ( 2 ) or the sub-beam ( 32 . 33 ; 35 . 36 ; 41 to 43 ) is different, such that the material ( 5 ) on page on which the beam ( 2 ) or the partial beam ( 32 . 33 ; 35 . 36 ; 41 to 43 ) on the material ( 5 ), is the least. Method according to one of claims 1 to 8, characterized in that the cross-sectional shape of the beam ( 2 ) or the partial beam ( 32 . 33 ; 35 . 36 ; 41 to 43 ) during the irradiation of the material ( 5 ) is changed. Contraption ( 100 ) for carrying out a method according to one of claims 1 to 9, with a laser beam source ( 11 ) trained radiation source ( 10 ) and one in the beam path of the beam ( 2 ) arranged beam-shaping element ( 20 ).

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