DE102019201474A1 - DEVICE FOR GENERATIVE ASSEMBLY OF A COMPONENT - Google Patents

Abstract

The present invention relates to a device (1) for the generative construction of a component (2), with a material receptacle (4) for receiving a material (3) held in an informal or neutral manner, a beam source (7) for emitting a beam (6) for irradiation the material receptacle (4) on a construction surface (5), a tilting unit (8), by means of which the beam (6) can be moved over the construction surface (5), and distortion optics (10) over which the beam (6) of the construction surface (5) is guided upstream, the distortion optics (10) distorting the beam (6) at an oblique incidence on the construction surface (5) in such a way that a cross-sectional profile (6.1) of the beam (6) - in a plane of incidence (30), which is spanned by the beam (6) and a surface normal (11) on the construction surface (5), is compressed, and / or is widened in a transverse plane (31) perpendicular to the plane of incidence (30).

Description

Technical field

The present invention relates to a device for the generative construction of a component.

State of the art

Generative manufacturing processes not only allow prototypes to be set up quickly, but because of their geometry it is also possible to manufacture components or components with certain material properties that are otherwise difficult to manufacture. The structure is built up in layers, and geometries can also be created that would not be accessible, for example, with a casting process. In so-called powder bed processes, the material is kept in powder form and applied sequentially layer by layer. After the application of a respective layer, it is selectively irradiated and thus solidified in a desired area by melting the powder as a result of the irradiation. The next powder layer is then applied and solidified in some areas according to the component geometry to be produced.

A corresponding manufacturing device has a material receptacle in which the informal or neutral material is arranged. A radiation source is provided for the radiation, the beam of which can be moved by means of a tilting unit over the material receptacle, that is to say over a construction surface. In conjunction with a selective switching on and off of the radiation, a respective layer on the construction surface can be irradiated in a specific area and the material can thus be solidified in some areas.

Presentation of the invention

The present invention is based on the technical problem of specifying a particularly advantageous device for the generative construction of a component.

This is achieved according to the invention with the device according to claim 1. In addition to the beam source and tilting unit, this has a distortion optic, via which the beam is guided upstream of the construction area. With the distortion optics, the cross-sectional profile of the beam is distorted in the event of an oblique incidence on the construction surface. This can counteract a distortion of the spot shape that results from an obliquely incident beam for reasons of geometry. If you imagine the beam as a cylinder, for example, the oblique incidence on the construction surface results in an elliptical shape (oblique cylinder section). With such an elliptical or generally distorted spot, the coupled energy can then e.g. B. depending on the scanning direction. For example, more movement is introduced locally when moving along the large ellipse half axis (longitudinal) than when moving along the small ellipse half axis (transverse). This problem can be prevented with the distortion optics. In simple terms, the beam can be distorted upstream of the construction area in such a way that distortion due to the oblique incidence is compensated for, so the resulting spot is distortion-free.

Further preferred embodiments can be found in the dependent claims and the entire disclosure, wherein the representation of the features does not always differentiate in detail between method and device aspects; in any case, the disclosure is to be read implicitly with regard to all claim categories. If, for example, a specific embodiment in accordance with the method is described, this should also be read on a device which is set up to carry out a corresponding method.

• - in einer Einfallsebene gestaucht wird und/oder
• - in einer zu der Einfallsebene senkrechten Transversalebene geweitet wird.

In particular, the distortion of the spot in the case of oblique incidence is counteracted by using a cross-sectional profile of the beam with the distortion optics

• - is compressed in a plane of incidence and / or
• - is expanded in a transverse plane perpendicular to the plane of incidence.

The beam, especially its central axis, spans the plane of incidence together with a surface normal on the construction surface. The center axis lies in the center of the beam and passes through the construction area where the surface normal has its base (in the center of the spot). The transverse plane perpendicular to the plane of incidence also contains the central axis of the beam; in other words, the center axis of the beam is the intersection of the plane of incidence and the transverse plane.

The cross-sectional profile of the beam is viewed in a plane perpendicular to its center axis, namely in front of the construction area (before the beam hits the construction area). The information "upstream" and "downstream" generally refers to the radiation direction, i.e. the path of the beam from the beam source to the construction area. Insofar as reference is made to the spread of the beam or its profile, this is to be read with regard to the device in such a way that it is set up for an operation in which such beam spread takes place.

In a preferred embodiment, the beam has a circular cross-section in front of the Verzerroptik and an elliptical cross-section profile downstream of the Verzerroptik. Meets such an ellipse distorted beam then onto the construction area, this results in a circular spot. The elliptical cross-sectional profile can in particular be oriented such that a line of intersection with the plane of incidence produces the small semi-axis and a line of intersection with the transverse plane results in the large semi-axis.

According to a preferred embodiment, the distortion optics are adaptive, that is, the strength of the distortion can be adjusted. The beam or its cross-sectional profile can thus be distorted the more, the more obliquely it falls on the construction surface, the greater the angle of incidence. The latter is taken between the center axis of the beam and a surface normal placed in the spot in the construction area. With the adaptation, a spot of the same shape can be created anywhere on the construction surface, preferably also of the same size (radius or diameter) and intensity distribution.

In a preferred embodiment, a dynamic focusing unit is additionally provided, with which the beam cross section can be reduced and enlarged without distortion. The beam can thus be focused to different degrees at different angles of incidence in order to counteract a variation in the spot size that would result from the different levels of distortion. If the beam falls on the building surface at a larger angle of incidence and if the distortion optics distort it correspondingly more, stronger focusing can result in the same spot size as with a smaller angle of incidence, in which the beam distorts less with the distortion unit and also with it the focusing unit is less focused. For example, a lens system (rotationally symmetrical about the optical axis) can be provided as the focusing unit, wherein the different focusing can be achieved by a relative offset of the lenses.

In general, the beam can also be an electron beam, which is adjusted in electron microscopy. In a preferred embodiment, however, a laser source is provided as the beam source, which emits a laser beam during operation. The cross-sectional profile of the laser beam is preferably round, the intensity distribution is typically Gaussian. The laser source can be, for example, a CO2 laser, Nd: YAG laser or Yb fiber laser or a diode laser.

In principle, the distortion optics can also be implemented reflectively, that is to say using a mirror system. In a preferred embodiment it is a refractive optics, the beam is thus shaped by refraction.

According to a preferred embodiment, the Verzerroptik on a first and a second prism, which form an anamorphic pair of prisms. The laser beam passes through it, resulting in different-sized imaging scales on two mutually perpendicular axes (in the case of the ellipse, these are the small and the large semi-axis). The first and the second prism are preferably mounted such that they can be tilted relative to one another, the ratio of the imaging scales being able to be changed by changing the relative tilting. If the laser beam falls on the building surface at a small angle, only a small difference in the imaging scales is required for compensation, whereas a larger difference is set at a large angle of incidence.

Distortion of the laser beam can also be achieved by means of cylindrical lenses which are arranged in succession in the beam path. For example, convex cylindrical lenses can be provided, and the cross-sectional profile can thus be widened. In the plane in which the cylinder axes lie, however, it remains unchanged. This results in the desired asymmetry of the image, i.e. the distortion. When viewed in a sectional plane perpendicular to said cylinder axis, the cylinder lenses can be arranged, for example, telecentrically, preferably both on the beam source side and on the construction surface side.

In a preferred embodiment, the cylindrical lenses are mounted such that they can be displaced relative to one another in the distortion optics, ie their distance in the radiation direction can be changed. This enables the cross-sectional profile to be adapted adaptively, that is to say a greater distortion at large and a lower distortion at small angles of incidence. In particular, one cylindrical lens can be arranged in a fixed position in the distortion optics and only the other lens can be displaceably mounted (but both lenses can also be displaceably mounted).

According to a further preferred embodiment, the Verzerroptik has an aperture through which the laser beam passes. The aperture limits the cross-sectional profile of the laser beam on two mutually perpendicular axes to different extents, namely, in the case of the preferred circular or elliptical shape, more on the small semi-axis. Metaphorically speaking, part of the beam is cut away there in order to set the desired cross-sectional profile. The diaphragm can in particular be a field diaphragm. An arrangement or a structure can preferably be a spatial filter, that is to say a converging lens can be arranged in front of the diaphragm. This bundles the beam, so the aperture can be chosen to be correspondingly small (also known as a pinhole with a diameter of only a few 10 µm).

In a preferred embodiment, the diaphragm is adjustable, so the profile of its diaphragm opening can be changed. This does not concern or not only the opening width, but in particular the opening ratio on two mutually perpendicular axes. The change is greater on one axis than on the other, so it is possible, for example, to set ellipses with different ratios from small to large semiaxis (up to a circular shape). This means that the beam entering at a large angle can be distorted more than the beam entering at a small angle or perpendicularly.

In a preferred embodiment, the tilting unit is a tiltably mounted mirror, for example a galvanometrically mounted scanner mirror. The tiltably mounted mirror is preferably arranged essentially centrally above the construction area, so that a perpendicularly incident beam strikes the construction area in the center. The angles of incidence correspondingly become larger towards the edges of the building surface. The Verzerroptik is preferably upstream of the tilting unit, that is, in particular the tiltable mirror. If a dynamic focusing unit is provided in a preferred embodiment, this can be arranged upstream of the distortion optics, ie between the beam source and the distortion optics.

In general, an advantage of the device according to the invention can lie in a comparatively compact arrangement of the beam source, tilting unit and distortion optics. If the beam shaping of the tilting unit is carried out upstream, no great weight has to be moved with the tilting unit, which simplifies the suspension etc. In order to obtain a spot shape that is constant over the construction area in an alternative way to the present object, the beam could also be directed onto the construction area via a telecentric F-theta lens, for example. Due to the infinite image, the beam would always fall perpendicularly onto the construction surface, regardless of its position. However, such a lens would have to be almost as large as the construction area and could at best be manufactured with great effort and thus costly.

The invention also relates to a method for the generative construction of a component. A material which is held in a formless or shape-neutral manner is then arranged in the material receptacle, in general for example also a liquid, preferably a powder, in particular a metal powder. The construction area lies on the surface of the material (on the surface of the respective processed layer). To solidify a certain area, the beam is then moved over the building surface by means of the tilting unit, where irradiation is carried out for solidification. Furthermore, in order to compensate for distortion in the case of oblique incidence, the cross-sectional profile is compressed in the plane of incidence and / or expanded in the transverse plane. For the rest, reference is expressly made to the above statements, which may also be of interest in the case of the procedure.

The invention also relates to the use of a device disclosed here for the generative construction of a component which is designed as a component of an axial turbomachine, in particular an aircraft engine.

Figure list

The invention is explained in more detail below on the basis of an exemplary embodiment, the individual features within the framework of the subordinate claims also being essential to the invention in a different combination and furthermore not being distinguished in detail between the different claim categories.

• 1 eine erfindungsgemäße Vorrichtung in einer schematischen, teilweise geschnittenen Seitenansicht;
• 2 Spotformen auf einer Baufläche der Vorrichtung gemäß 1, ohne Anpassung durch die Verzerroptik;
• 3 zeigt Möglichkeiten zur Anpassung des Querschnittsprofils mit der Verzerroptik;
• 4 zeigt eine erste Möglichkeit zur Gestaltung einer Verzerroptik;
• 5 zeigt eine zweite Möglichkeit zur Gestaltung einer Verzerroptik;
• 6 zeigt eine dritte Möglichkeit zur Gestaltung einer Verzerroptik.

In detail shows

• 1 a device according to the invention in a schematic, partially sectioned side view;
• 2nd Spot forms on a construction surface according to the device 1 , without adjustment through the distortion optics;
• 3rd shows options for adapting the cross-sectional profile with the distortion optics;
• 4th shows a first way to design a Verzerroptik;
• 5 shows a second way to design a Verzerroptik;
• 6 shows a third way of designing a verro optics.

Preferred embodiment of the invention

1 shows a device 1 for the generative construction of a component 2nd from one material 3rd which is held in powder form. The material 3rd is in a material intake 4th arranged, it is on a construction area 5 solidified in layers by melting the powder. Then the part of the component that has been manufactured so far 2nd lowered (not shown in detail) and the next powder layer is applied and on the construction area 5 solidified.

The solidification takes place by irradiation with a beam 6 , namely a laser beam. This process is also known as selective laser beam melting (SLM). For emission of the beam 6 is a radiation source 7 provided, in the present case a laser source. To the beam 6 to different areas of the construction area 5 to be able to steer it via a tilting unit 8th led that is equipped with galvanometrically mounted scanner mirrors. The beam arrives depending on the tilt position of the mirror 6 to a corresponding X / Y position of the construction area 5 . In the in 1 shown situation he is deflected towards the edge, dotted is a central idea for comparison (at a different time).

The following is first up 2nd referred before 1 is discussed further in detail. 2nd shows the construction area 5 in a supervision, i.e. against the Z direction in 1 looking at it from above. A spot can be seen 20 (dotted) the beam 6 generated with central incidence. There is also a spot 21 shown the beam 6 on the edge of the construction area 5 generated. Because of the oblique incidence there is the spot 21 no longer circular, but elliptical. Becomes such a spot 21 over the construction area 5 moves, the coupled energy depends on the scanning direction, compare the introduction to the description in detail.

In the device according to the invention 1 , which are now referenced again 1 is therefore described as distorted 10th arranged in the beam path with a cross-sectional profile 6.1 of the beam 6 is distorted. The cross-sectional profile 6.1 becomes perpendicular to the central axis 6.2 of the beam 6 viewed, it is circular without distortion.

3rd illustrates how the cross-sectional profile 6.1 can be adjusted in the oblique incidence, so that on the construction area 5 despite the oblique idea, the result is a round profile. The cross-sectional profile 6.1 can do this on a level of inspiration 30th compressed (small ellipse) and / or in a transverse plane 31 be expanded (large ellipse). The plane of incidence 30th is from the center axis 6.1 of the beam 6 together with a surface normal 11 open, compare 1 . The transverse plane 31 is perpendicular to it and also includes the central axis 6.1 .

Will the cross-sectional profile 6.1 widened transversely, the resulting spot has 22 (dashed in 2nd ) a correspondingly larger diameter. To the spot size over the construction area 5 The device has to keep constant 1 according to 1 additionally a dynamic focusing unit 12th on. This is equipped with lenses, the relative distance of which depends on the deflection of the beam 6 is changed so that the edge is focused more than the center.

How out 1 visible, the laser radiation comes from the beam source 7 via the dynamic focusing unit 12th and the distortion optics 10th to the tilting unit 8th . From there it is through a protective glass 13 into the process chamber 14 coupled. The following are different ways of building the verro optics 10th discussed.

4th shows distortion optics 10th that have a first prism 40 and a second prism 41 having. The prisms 40 , 41 form an anamorphic pair of prisms, the cross-sectional profile 6.1 will on the axis 42 widened on the axis 43 however not. The prisms 40 , 41 are tiltable, by changing the inclination, i.e. the angle 44 , 45 , the distortion (widening on the axis 42 ) change. So that the cross-sectional profile 6.1 depending on the X / Y position on the construction area 5 with increasing angle of incidence 15 become increasingly distorted.

5 shows distortion optics 10th with a first cylindrical lens 50 and a second cylindrical lens 51 . The cylindrical lenses 50 , 51 are translationally symmetrical perpendicular to the plane of the drawing. The arrangement of the cylindrical lenses 50 , 51 is telecentric on both sides (object and image point in infinity). In the distortion optics 10th is the second cylindrical lens 51 moveable, the distance to the focal plane 52 the first cylindrical lens 50 is changeable. Will be the second cylindrical lens 51 in 5 offset to the left, the distortion is reduced, the cross-sectional profile 6.1 will be on the axis 42 less widened. Will be the second cylindrical lens 51 however, shifted to the right increases the distortion. This allows an adaptive, with increasing angle of incidence 15 achieve increasing distortion.

6 shows another way to build a verro optics 10th , the cross-sectional profile 6.1 with an aperture 60 is adjusted. The aperture 60 is with an elliptical, adjustable aperture 61 intended. By adjusting the aperture 61 can the cross-sectional profile 6.1 between a circular shape and one on the axis 42 spread ellipse can be varied.

The aperture 60 upstream is a converging lens 62 provided, the arrangement represents a so-called spatial filter. With a collimation lens 63 the beam of rays becomes the spatial filter 60 , 62 collimated downstream.

Reference list

1

contraption

2nd

Component

3rd

material

4th

Material intake

5

Building area

6

beam

6.1

Cross-sectional profile

6.2

Center axis

7

Radiation source

8th

Tilting unit

10th

Distorted optics

11

Surface normal

12th

Focusing unit

13

Protective glass

14

Process chamber

15

Angle of incidence

20

Spot (middle)

21

Spot (on the edge)

22

Spot (compensated)

30th

Plane of incidence

31

Transverse plane

40

First prism

41

Second prism

42

axis

43

axis

44

angle

45

angle

50

First cylindrical lens

51

Second cylindrical lens

52

Focal plane

60

cover

61

Aperture

62

Converging lens

63

Collimation lens

Claims (15)

Device (1) for the generative construction of a component (2), with a material holder (4) for holding an informal or neutral material (3), a beam source (7) for emitting a beam (6) for irradiating the material receptacle (4) on a construction surface (5), a tilting unit (8), by means of which the beam (6) can be moved over the construction surface (5), and Verzerroptik (10), over which the beam (6) of the building surface (5) is guided upstream, the distortion optics (10) distorting the beam (6) in the event of an oblique incidence on the building surface (5) such that a cross-sectional profile (6.1) of the beam (6) - In a plane of incidence (30), which is spanned by the beam (6) and a surface normal (11) on the construction surface (5), compressed, and / or - Widened in a transverse plane (31) perpendicular to the plane of incidence (30). Device (1) after Claim 1 , in which the cross-sectional profile (6.1) of the beam (6) has an elliptical shape downstream of the Verzerroptik (10) and the beam (6) generates a circular spot (22) on the construction surface (5). Device (1) after Claim 1 or 2nd , in which the distortion optics (10) are designed adaptively and the device (1) is set up for operation in such a way that the beam (6) with the adaptive distortion optics (10) is increasingly distorted with increasing angle of incidence (15). Device (1) after Claim 3 , which additionally has a dynamic focusing unit (12), via which the beam (6) is guided upstream of the building surface (5), the device (1) being set up for operation in such a way that the beam (6) with the dynamic focusing unit (12) at different angles of incidence (15) to adjust the spot sizes generated on the construction surface (5) to different degrees. Device (1) according to one of the preceding claims, in which the beam source (7) is a laser source and the beam (6) is a laser beam. Device (1) after Claim 5 , in which the Verzerroptik (10) is refractive and is penetrated by the laser beam. Device (1) after Claim 6 , in which the Verzerroptik (10) has a first prism (40) and a second prism (41), which form an anamorphic pair of prisms (40, 41), which the laser beam passes through at an oblique incidence. Device (1) according to the Claims 3 and 7 , in which the first and second prisms (40, 41) are mounted such that they can be tilted in relation to one another in the distortion optics (10) and the cross-sectional profile (6.1) of the laser beam can be adapted as a function of the angle of incidence (15) by changing the relative tilting. Device (1) according to one of the Claims 6 to 8th , in which the Verzerroptik (10) has a first cylindrical lens (50) and a second cylindrical lens (51), which the laser beam passes through in the oblique incidence. Device (1) according to the Claims 3 and 9 , in which the first and the second cylindrical lens (50, 51) in the Verzerroptik (10) relative to each other are displaceable and the cross-sectional profile (6.1) of the laser beam can be adjusted as a function of the angle of incidence (15) by changing the relative distance. Device (1) according to one of the Claims 6 to 10th , in which the Verzerroptik (10) has an aperture (60) through which the laser beam passes through at an oblique incidence, the aperture (60) limiting the cross-sectional profile (6.1) of the laser beam on two mutually perpendicular axes (42, 43) to different extents . Device (1) after Claim 11 combined with Claim 3 , in which an aperture (61) of the aperture (60) is adjustable. Device (1) according to one of the Claims 6 to 12th , in which the tilting unit (8) is a tiltably mounted mirror, via which the beam (6) is guided onto the building surface (5), the distortion optics (10) being arranged in front of the mirror. Method for the generative construction of a component (2) with a device (1) according to one of the preceding claims, in which method - A shapeless or shape-neutral material (3) is arranged in the material receptacle (4); - The beam source (7) emits a beam (6) which is moved with the tilting unit (8) over the construction surface (5), the material (3) being selectively irradiated; - The beam (6) with the Verzerroptik (10) at an oblique incidence on the construction surface (5) in the plane of incidence (30) compressed and / or expanded in the transverse plane (31). Use of a device (1) according to one of the Claims 1 to 13 For the generative construction of a component (2) which is designed as part of an axial turbomachine, in particular an aircraft engine.

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