EP4126424A2

EP4126424A2 - Apparatus for additively manufacturing components, in particular by means of selective melting or sintering

Info

Publication number: EP4126424A2
Application number: EP21713357.8A
Authority: EP
Inventors: Rainer Kurtz
Original assignee: Kurtz & Co Kg GmbH
Current assignee: Kurtz & Co Kg GmbH
Priority date: 2020-03-23
Filing date: 2021-03-16
Publication date: 2023-02-08
Also published as: WO2021191006A3; KR20220153650A; WO2021191006A2; JP2023519533A; CN115348908A

Abstract

The invention relates to an apparatus for additively manufacturing components, in particular by means of selective melting or sintering, said apparatus comprising: a light source for generating a light beam; and a machining head which either is coupled to the light source by means of a beam guide so that the light beam is guided to the machining head, or the light source is positioned directly on the machining head so that a light beam can be directed from the machining head onto a machining region, the machining head being movably mounted so that the light beam can be directed to any desired location in the machining region. The invention is characterised in that several machining heads are provided each for directing a light beam on the machining region, and the machining heads are each positioned on a carriage which can be moved along a traverse. This makes it possible to melt or sinter powder simultaneously at several locations. Preferably, the machining heads are positioned on swivel arms. This makes it possible to design the device in a very simple and cost-effective manner.

Description

Device for the generative production of components, in particular by means of selective melting or sintering

The present invention relates to a device for the generative production of components, in particular by means of selective melting or sintering.

DE 10 2016 222 068 A1 discloses a device and a method for generative component production with several spatially separated steel guides. A processing head has several optical switching elements via which several beams can be directed to the target position. The machining head is aligned displaceably on a linear axis. The linear axis is in turn mounted displaceably on a linear axis that is perpendicular to it. This enables an X-Y movement. The laser beam source or sources are attached to the linear axis.

WO 2018/202643 A1 discloses a device for additive manufacturing by selective laser sintering. One or more lasers are assigned to one or more laser heads. These lasers are distributed to the individual heads via the beam splitter. The heads can be moved over rails in the X and Y directions. The heads can be moved independently of one another. The light is fed to the heads using mirrors.

From US 10,399,183 B2 an additive manufacturing process emerges in which an optical head is supplied with a laser beam via a glass fiber. As a result, several laser beams can be directed to the same head and executed in parallel from this. This enables parallel melting points on the surface of the powder bed.

A similar method is described in US Pat. No. 10,399,145 B2.

US 2015/0283612 A1, US 2014/0198365 A1 and JP2009-65 09A disclose selective laser sintering devices which have a plurality of optical heads that emit laser beams be able to point at a powder bed. These heads themselves cannot be moved in the X and Y directions, but instead guide the laser beam into the corresponding positions via mirrors. The advantage here is that the location of the laser focal point can be changed quickly. In this case, however, the heads have to be comparatively far away from the powder bed and can only illuminate a limited area.

DE 10 053 742 C5 and US 9,011,136 B1 show devices for sintering with a cross slide arrangement, an additive manufacturing process with multiple heads for plastic printing and a device with a head that has both a 3D print and a 3D cutting element.

From US 2019/0009333 A1 a device and a method for selective laser melting emerges, wherein several parallel working laser heads are provided for melting a mate rials according to a powder bed-based laser melting. Each of the laser heads can be moved along a linear traverse and the laser heads can be moved independently of one another. The array of laser heads and the powder net surface can be rotated horizontally relative to each other.

US 2017/0129012 A1 describes a device and a method for the additive manufacture of components, the device comprising a plurality of robot arms on each of which a deposition head and a laser head are attached adjacent to one another. The robotic arms each include at least one swivel joint and are designed to move the deposition head and the laser head in all three spatial directions. Material can be applied to a processing surface by means of the deposition head and this point can be melted with the laser immediately afterwards.

From CN 106 312 574 A a device emerges, comprising equipment for additive manufacturing processes as well as for milling processes. The device essentially comprises several robot arms which can be equipped with gripping elements for providing material on a work platform or for removing finished components or with a laser head. The robot arms each have two joints and are therefore rotatably and pivotably mounted. The device further comprises a central production arm, which can be equipped with a laser head or a milling head. The central production room can be moved linearly along a traverse.

DE 10 2018 128 543 A1 has a laminating molding device in which two laser heads operating in parallel are used to melt a material in accordance with a laminating molding process are provided. Both laser heads are coupled to a traverse and can be linearly moved independently of one another. The traverse can also be moved. In this way, the machining area can be completely covered. The laser beam is guided to the processing area by a focusing unit using two mirror elements.

From CN 206 065 685 U a device and a method for 3D printing emerge, with a laser for melting a starting material and a cutting laser for processing the structures produced are provided. The laser for melting a starting material and the cutting laser can be moved independently of one another along several crossbars, both horizontally and vertically.

The invention is based on the object of creating a device for the generative production of components, in particular by means of selective melting or sintering, which is simple in design, allows a high production speed and with which 3D components can be produced with high precision.

The object is achieved by a device with the features of claim 1, by a device with the features of claim 13, by a device with the features of claim 18 and by a device with the features of claim 24 ge. Advantageous refinements are given in the subclaims.

A device according to the invention for the generative production of components, in particular by means of selective melting or sintering, comprises a light source for generating a light beam, a processing head which is either coupled to the light source with a beam guide so that the light beam is guided to the processing head, or the light source is arranged directly on the processing head, so that a light beam can be directed from the processing head to a processing area, the processing head being movably mounted so that the light beam can be directed to different locations in the processing area, and with several processing heads for directing a light beam are provided on the processing area, and the Bear processing heads are each arranged on a slide which can be moved along a cross member.

The device is characterized in that the machining heads are each arranged on one of the slides by means of a swivel arm which can be swiveled about a vertical swivel axis. By providing several processing heads, several bundles of light beams can be directed onto the processing area at the same time, so that several points in the processing area can be melted or sintered in parallel. The machining heads are arranged on or on a slide and can be moved along a cross member. This allows simple and reliable positioning of the machining heads over the machining area.

By providing swivel arms for the machining heads which can be swiveled about a vertical swivel axis and which are each arranged on a slide, the machining heads can be quickly positioned over a large section of the machining area at any point. This section extends around the traverse along which the respective slide with the respective machining head can be moved in an area around the pivot axis of the pivot arm, which extends on both sides by a width that corresponds to the length of the pivot arm. This section is thus strip-shaped around the crossbeams with a width which corresponds approximately to twice the length of the pivot arms. This strip-shaped section is referred to below as the cover area, since the machining heads, which are arranged on the carriage of a cross-beam, can be arranged at any position within the cover area and thus impinge on the machining area with a bundle of light beams at any point in the cover area or can cover.

The swivel arms can be designed to be swivelable only about the vertical axis. Such a configuration is very simple compared to multi-axis robot arms. Nevertheless, the processing heads can be positioned very quickly and precisely and the parallel processing achieves a high throughput.

The swivel arms can be designed with a length of, for example, at least 5 cm, preferably at least 10 cm or at least 15 cm, and in particular at least 20 cm. The longer the swivel arms, the wider the coverage areas.

It can be useful to position the processing heads only in a restricted Winkelbe area of the swivel arms, because the more the swivel arms swivel the processing head away from the traverse, the more imprecise the position of the processing head in the direction parallel to the traverse. The angular range can, for example, be limited to a maximum swivel angle with respect to the traverse of a maximum of 60 ° or a maximum of 45 ° will. With a maximum swivel angle of 45 °, the width of the coverage area is reduced to the length of the swivel arm.

The device can have a plurality of cross members which are arranged parallel to one another. The crossbars are preferably spaced apart such that the cover areas overlap from adjacent crossbars.

The beam guide for the respective light beam can be formed with means of reflector elements along the pivot arms. This enables very light swivel arms, which have a low rotational moment of inertia, so that they can be swiveled quickly to any rotational position.

The pivot arms are preferably made of plastic, in particular made of fiber-reinforced plastic. At each of the pivot axis of the pivot arm remote th end, a mirror for directing the respective light beam on the processing area can be provided.

The beam guides can be designed at least partially as light guides. The Lichtlei ter can extend from the light source to the respective processing head. The respective light guide can, however, also only be guided from the light source to the pivotably mounted end of the respective pivot arm and there be arranged with its end in such a way that the light beam is coupled into a beam guide along the pivot arm, which is formed by means of reflector elements. Such a design has the advantage that the swivel arm can be rotated through 360 ° or more without the light guide having to be rotated. The end of the light guide at which the light from the light guide is coupled into the beam guide on the swivel arm can be arranged in a stationary manner with respect to the slide to which the swivel arm is attached.

The end of the light guide can alternatively be arranged in a stationary manner on the swivel arm in such a way that the light beam is emitted in the direction of the free end of the swivel arm, preferably parallel to the swivel arm. At the free end of the swivel arm, a reflector element for directing the respective light beam onto the processing area can be seen, such as a deflecting mirror.

The reflector element can be a parabolic mirror or a mirror with a free-form surface for bundling the light, so that no optical lens is necessary in the beam path. The traverses on which the slides are movably mounted can be stationary angeord net. This is particularly advantageous in connection with an embodiment with processing heads arranged on swivel arms, since such a fixed arrangement can be controlled much more easily to avoid collisions between different swivel arms than in a device in which the swivel arms can be swiveled, the carriages can be moved along the traverses and the Traverses themselves can be moved transversely to their longitudinal direction. In addition, with a fixed arrangement of the crossbars and swivel arms on the carriage with a few crossbars, full coverage of the processing area can be achieved, provided the swivel arms are not too short. Since the processing heads arranged at the free ends of the swivel arms can be very light, for example only by means of a small mirror, even with longer swivel arms with a length of, for example, at least 10 cm, preferably at least 15 cm, and in particular at least 20 cm, a little Rotational moment of inertia can be achieved.

The device can be designed so that one or more cross members can be retrofitted. In this way, on the one hand, the processing area can be subsequently enlarged and, on the other hand, the density of cross members and thus of processing heads in a predetermined processing area can be increased. With an increase in the density of the traverses and thus a decrease in the distance between the crossbars, it may be useful to attach the swivel arms to the carriage so that they can be replaced with a shorter distance between the crossbars, correspondingly shorter swivel arms.

At least two carriages which can be moved independently of one another are preferably mounted on each cross member, each carriage having a machining head. It is also possible for more than two carriages, for example three or four carriages, to be provided per traverse.

A plurality of light sources are preferably provided, each of which is assigned to one or more processing heads. The light sources are preferably lasers, in particular CO2 lasers or ND: YAG lasers. CO2 lasers are mainly used for melting or sintering plastic powder. ND: YAG lasers are used for melting or sintering metal powder. Such a CO2 laser has, for example, a light output of 30 W to 70 W and an ND: YAG laser of 100 W to 1,000 W and more. The light sources can also be light-emitting diodes, in particular special super-luminescence light-emitting diodes, and / or semiconductor lasers. By providing several light sources and several processing heads, which can be positioned independently of one another in the processing area, it is possible for powder to be melted or sintered simultaneously at several points in the processing area in order to produce a 3D component. This simultaneous melting or sintering of the powder increases the production speed of additive manufacturing with the present device compared to conventional devices. Even if the processing heads remain a little longer at the individual points, a high production speed can be achieved. This also makes it possible for light sources with a comparatively low light output to be used. This significantly lowers the cost of the device.

A multiplexer can be provided to distribute the light beam from one of the light sources to different beam guides. Such a multiplexer is preferably useful for very bright light sources with which the powder can be melted or sintered with short pulses. In the processing area, the device preferably has a powder bed in which there can be powder that is selectively melted by means of the light beam.

The powder can be a metal powder or a plastic powder.

The individual swivel arms can be arranged at different heights in order to avoid collisions when moving the swivel arms.

The individual light sources can be designed so that they emit light beams with different frequencies or different frequency ranges and / or different intensities. This allows the selective melting or sintering process to be controlled individually. This allows, for example, a control of the porosity of the product made with it.

The light beam can also be focused on the processing area to different degrees. The focusing can be set, for example, by means of an objective and / or a height adjustment of the processing heads.

With the device according to the invention, powder can be melted or sintered simultaneously in a powder bed at several points. An inert gas atmosphere, in particular a nitrogen and / or argon atmosphere, can be formed in the entire device. By using an inert gas atmosphere, oxidation of the powder or the component can be prevented during component production. With the formation and maintenance of the inert gas atmosphere, it is possible to filter dirt particles from the interior of the device in a simple manner.

According to a further aspect of the invention, a device for the generative production of components, in particular by means of selective melting or sintering, is provided, with a processing table with a preferably horizontal table top which forms a support surface for the powder bed, the processing table via a table top at least at least partially laterally delimiting wall, and the table top and the wall jointly define the processing area. The device is characterized in that the wall can preferably be moved perpendicular to the table top.

When manufacturing a component, the wall is moved vertically relative to the processing table after one or more component layers created. For this purpose, the top of the wall can form a flat surface with the table top of the processing table at the beginning of the component production. Powder is applied to the tabletop and smoothed out. A powder layer can have a thickness of about 20 μm - 100 μm. The first component layer is then created by connecting at least some of the powder particles. The connection can take place by melting and cooling, by sintering or by applying a binding agent locally. After the first component layer has been produced, the wall can be moved upwards by the fleas of the first component layer. In this way, a chamber is formed between the wall and the support surface. The powder bed is formed in this chamber. The powder bed comprises the component layer that has already been formed and the remaining powder that is not connected to one another. Then another layer of powder can be applied, smoothed out and a second component layer can be manufactured. The height of the wall can then be adjusted again by the thickness of the second component layer. The chamber formed by the wall and the support surface is enlarged in this way in the vertical direction and then comprises the two component layers and the remaining, non-interconnected powder material. The aforementioned steps are repeated until the component is completely manufactured. The wall, which is usually lighter than the machining table, can be moved with little effort. The wall can be moved according to one or more layers formed. It is advantageous if the processing table is designed to be stationary and not movable. The known structure, namely that the machining table is moved downwards relative to the stationary wall surrounding the machining table during component production, can thus be reversed. In the case of a device for the additive manufacturing of components with a base area of the processing table of 1.5 mx 1 m and a stroke of 0.5 m, a working volume of 0.75 m ³ results. If this working volume is filled with aluminum powder, the contents weigh about 2 t. In the case of steel powder, the weight is around 61. Since only the wall, which is usually significantly lighter than the processing table and the additively manufactured object on it, has to be moved, a small and inexpensive drive can be used. The structure of the Be work table can at the same time be designed to be particularly inexpensive but still stable, since the work table does not need to be moved. This further reduces the overall costs of the device.

An electric, pneumatic and / or hydraulic drive, for example, can be used to adjust the wall vertically.

The wall can be provided on its upper edge with an outwardly horizontally protruding collar, which prevents powder from falling onto a foundation in areas that are not intended for this. The collar can only be provided on one side of the powder bed or can be formed on several or even circumferentially.

The wall can be formed from several wall sections, wherein the Wandab sections can be moved individually and / or together. Individual sections of the wall can then be moved independently of one another. The wall can thus be adjusted to a large number of possible applications.

An order dispenser can be provided for applying powder to be selectively melted or sintered onto the processing table or onto the processing area. The order dispenser can be moved in the horizontal direction over the processing table in order to be able to distribute the powder over the entire processing area. The order dispenser can have a doctor blade or be coupled to a doctor blade, so that the powder applied is smoothed out. By using an order dispenser, the installation space or the base area of the device can be reduced, since a Vorratszylin can be dispensed with. The use of a supply cylinder instead of an order dispenser can, however, be advantageous in order to reduce the turbulence in the atmosphere inside the device, which is caused by the movement of the order dispenser. The wall can be moved together with at least one further component, preferably a light source and / or a processing head and / or a doctor blade and / or an application dispenser for applying powder material and / or a storage cylinder. It is particularly advantageous if the machining heads can be adjusted in height together with the wall. In this way it can be ensured that the processing heads always have the same distance from the processing area or from the surface of the powder bed. A complex setting of an optimal distance between the machining head and the machining area can thus be dispensed with, as can the re-focusing or setting of the optics of the machining head. The person skilled in the art knows which components, depending on the structure of the device, should preferably have a constant distance from the wall or from the processing area or from one another during component production. These components can be designed to be movable coupled with the wall. Only a single drive is then required to move these components relative to the machining table, which means that the structure is simple.

The wall can be moved depending on the thickness of the next component layer to be formed. It is possible for the individual component layers to have different thicknesses. Thus, during production, individual component layers can be made thicker than others if a high degree of partial accuracy is not important in the corresponding component areas. If, on the other hand, a high degree of dimensional accuracy is important in individual component areas, the component layer to be manufactured can have a smaller thickness. In this way, component production can be accelerated in individual component areas and thus as a whole. The component can thus be manufactured particularly quickly depending on the dimensional accuracy required in the respective areas.

In a preferred embodiment, a collecting device is provided, preferably designed as a collecting basin in order to receive excess powder that comes out of the processing area. During production, powder can get rich from the processing area, for example powder can be pushed through the squeegee from the processing table or from the table top or from the collar. This excess powder can be picked up by the collection device. In a particularly simple embodiment, the collecting device can be formed by a collecting or collecting basin into which the excess powder falls. This excess powder can then be collected and reused. The reservoir can be partially or fully dig be arranged around the work table, the wall and / or the collar, so that excess powder that is brushed from the work table, the wall and / or the collar can fall into the collecting basin.

A suction and a filter can be provided in order to suck off the excess powder, to filter it and to reuse it. The powder picked up by the collecting device is sucked off, then fed to a filter and conveyed back to the processing area in a circuit. The filter can filter out powder grains and / or dirt particles that are too large and / or already interconnected. A filter can, for example, have a filter size of 120 μm, so that only particles can pass through the filter which have a grain size of less than 120 μm. Depending on the powder and powder grain sizes used, different filter sizes can be used. The powder material cleaned in this way can be fed to a storage container and / or the order dispenser for reuse. Through this recirculation of the powder material, the material loss can be kept low. At the same time, it can be ensured that no powder grains that have already been connected to one another are reused or dirt particles are used. The use of already interconnected powder grains or dirt particles can lead to inaccuracies or flaws in the 3D component and have a negative effect on the stability or strength. The accuracy and quality of component production can still be ensured to a high degree by using an extraction system and a filter.

The work table can be tempered and kept at a predetermined temperature. In this way, stresses in the component, especially in the first layers, can be avoided. When Fierstellen a metal component, the work table can, for example, be heated to a temperature between 100 ° C and 300 ° C, preferably to a temperature between 150 ° C and 200 ° C. In the additive manufacturing of a plastic component, the temperature of the work table can be lower, for example between 40 ° C and 120 ° C, preferably between 60 ° C and 100 ° C. The temperature can be adapted to the material used.

Optics, in particular zoom optics, are preferably provided in order to change the focusing of the emitted light beam. The focusing of the light beam can easily be adapted to different distances from the processing area. At the same time, the energy input and the irradiated area can be changed through targeted focus adjustment. According to a further aspect of the invention, a device for the generative production of components, in particular by means of selective melting or sintering, is provided with at least one movable component, preferably a processing head and / or a processing table and / or a wall and / or a doctor blade and / or an order dispenser, and a drive for moving the movable component. The device is characterized in that at least one distance sensor is provided for preferably electro-optical distance measurement. The distance sensor can be arranged on or on the movable component and measure the distance to another object or the distance between the sensor and the other object. However, it is also possible for the distance sensor to be arranged on another object and to measure the distance to the movable component. In this way, the distance between the movable component and another object can be measured and determined at any time.

The distance sensor is preferably arranged in a stationary manner in order to measure the distance between the sensor and the movable component. In this way, the distance between a fixed point and the moving component can be measured and determined at any time. The movable component can have a reference object, the distance sensor detecting the reference object and measuring the distance to the reference object. A reflector, in particular a prism reflector, for example, can be used as the reference object. The distance sensor can be designed to be pivotable in order to be able to be aligned with the reference object.

The distance can be measured by means of triangulation and / or measurement of the phase position and / or measurement of the transit time. When measuring the distance by measuring the phase position, a laser beam is emitted. The phase shift of the reflected laser beam or its modulation with respect to the emitted beam depends on the distance. This phase shift can be measured and used to determine the distance traveled. The distance measurement by measuring the phase position has a high degree of accuracy. With laser triangulation, a light beam is focused on the measurement object and observed with a camera located next to it in the sensor, a spatially resolving photo diode or a CCD line. If the distance between the measuring object and the sensor changes, the angle at which the point of light is observed also changes and thus the position of its image on the photo receiver. The distance between the object and the laser projector is calculated from the change in position with the help of the angle functions. Distance measurement using triangulation is simple, inexpensive and yet very precise. When measuring the transit time, a light pulse or a modulated light beam is emitted. sends. The transit time is the time that the light beam needs to run from the source to a reflector, usually a retroreflector, and back to the source. By measuring this transit time, the distance between the source and the object can be determined using the speed of light. As an alternative or in addition, sensors can also be used for distance measurement that scan lines or areas or planes, or that can carry out spatial measurements, such as stereo cameras for three-dimensional localization of one or more objects. Corresponding sensors do not have to be designed to be pivotable due to their large recording area.

Instead of optical sensors, other sensors, such as ultrasonic sensors or sensors that determine the distance using the transit time of radio waves, can also be used.

In an advantageous embodiment, a control and regulating device is provided which is designed such that the movable component can be moved into a target position depending on the measured distance between the distance sensor and the movable component. The use of distance sensors together with a control and regulation system enables the use of an inexpensive and particularly light movement device for moving the movable component. An inexpensive and lightweight movement device has a low level of accuracy in positioning, but can therefore be moved particularly quickly. The position of the movable component can be regulated as a function of the distance between the movable component and the distance sensor. The closer the moving component approaches its target position, the slower the component can be moved. In this way it can be ensured that the movable component can reach the target position exactly. The movement device can be designed simply and, above all, light and inexpensive, since the precision of the movement and positioning is ensured by the distance measurement and the regulation in a closed control loop. Proportional controllers, so-called P controllers, proportional-integral controllers, so-called PI controllers, and / or proportional-integral-differential controllers, so-called PID controllers, can be used as controllers in the control loop.

Two, preferably three, distance sensors for distance measurement between the distance sensors and the movable component can be provided in order to determine the spatial position of the movable component. If the movable component is only moved in one plane, that is, in two dimensions, its position can be precisely determined by measuring the distance from two distance sensors. By measuring of three distances between the movable component and three stationary arranged distance sensors, the spatial position of the movable component can be determined exactly in three dimensions. If the movable component is only moved in one direction, a sensor can also be sufficient for distance measurement.

In a preferred embodiment, more than three distance sensors and at least two movable components are provided, each movable component being detectable in every position by at least three distance sensors for distance measurement. A distance sensor can be used to measure the distance between you and the two moving components. Depending on the positions of a first movable component, a distance sensor can be covered by this first movable component in such a way that a distance measurement to a second movable component is not possible. In such a case, the distance can be measured using another sensor that has direct optical access to the second movable component. This enables different or the same distance sensors to be used for each position determination of a movable component by distance measurement.

The distance sensors can be arranged in a stationary manner in the device, for example connected to the foundation of the device via a carrier. The distance sensors can determine the position of the surface of the powder bed via a distance measurement and then determine the position of a movable component, for example a machining head, with the aid of a further distance measurement. The processing head can be moved into a target position depending on the position of the powder bed, i.e. the fleas of the powder bed, in order to set the required distance between the processing head and the surface of the powder bed. One or more machining heads can be moved into their desired position with the aid of the control and regulating device described above. It is also possible that one or more distance sensors are connected to or arranged on a processing head and the distance between the processing head and the powder bed surface is determined in order to then move the processing heads to a target distance from the surface of the powder bed.

In addition, it is also possible for the position of one or more processing heads to be set as a function of the position of the movable wall, in particular an upper edge and / or a horizontal surface. To determine the distance between Seeing the movable wall and the processing head, one or more distance sensors can be connected to the processing head and / or arranged in a stationary manner in the device.

Instead of the position of one or more processing heads, the position of a traverse or another component of a direction of movement, for example a slide, can be determined and positioned relative to the movable wall or the surface of the powder bed. For this purpose, one or more distance sensors can be connected directly to the crossbeam and measure the distance to the surface of the powder bed.

In the same way, a doctor blade can also be positioned relative to the powder bed surface or a movable wall. For this purpose, at least one distance sensor can be connected to the doctor blade or arranged in a stationary manner in the device.

It is also possible to position an order dispenser depending on the position of the movable wall or the powder bed surface. For this purpose, the order dispenser can have at least one distance sensor or at least one distance sensor can be arranged in a stationary manner in the device.

The movable wall can also move relative to the surface of the powder bed, for example to a position that is one layer thicker than the powder bed. For this purpose, it is advantageous if the distance sensors are arranged in a stationary manner in the device.

In addition, it is also possible to move a storage cylinder relative to a machining table. In the case of a device of the aforementioned type, the processing table can also be moved in a controlled manner. For example, after the completion of a component layer, the processing table can be lowered by a defined layer thickness in order to be able to apply a new powder layer. In this way, the distance between the processing heads and the surface of the powder layer can be kept constant for each component layer to be created. The distance sensors are then preferably arranged in a stationary manner in the device.

It is also possible for several components to be coupled to one another together. For example, a squeegee can be positioned together with one or more processing heads and / or together with an order dispenser at a distance from the surface of the powder bed that is required in each case in the vertical direction. Of the vertical distance between the doctor blade and the processing heads and / or the order dispenser is then the same at all times.

Each movable component can be assigned three distance sensors for distance measurement. The same three distance sensors can be assigned to the same movable component for each distance measurement. However, it is also possible for the distance sensors to be reassigned to a component for each distance measurement. In this way, with each new distance measurement, each movable component can be assigned partially or completely different distance sensors than with a previous distance measurement.

According to a further aspect of the invention, a device for the generative production of components, in particular by means of selective melting or sintering, is provided, with a glass plate, the surface of which forms a support surface for powder, a processing area above the glass plate, a light source for generating a light beam, a processing head arranged below the glass plate, which is either coupled to the light source with a beam guide so that the light beam is guided to the processing head, or the light source is arranged directly on the processing head so that a light beam from the processing head through the glass plate onto the processing head can be steered processing area, wherein the processing head is movably mounted so that the light beam is directed to different points in the processing area who can. The device is characterized in that several processing heads are provided for each directing a bundle of light rays through the glass plate onto the processing area, the processing heads each being arranged on a slide which can be moved along a traverse.

With the aforementioned device, powder can be deposited on the surface of the glass plate, for example with the aid of an order dispenser. The glass plate forms a support surface for the powder. A doctor blade can be provided to smooth the powder layer. A support body can then be placed on the powder layer. A light beam can be directed from a processing head, which is arranged below the glass plate, through the glass plate to the corresponding areas with powder. The powder can be selectively melted or sintered and connected to one another, whereby a first component layer is formed on the support body. The component layer formed can then be raised together with the support body. For this purpose, a lifting device for supporting gripping and lifting of the component or the component layers may be provided in the vertical direction. The powder still on the glass plate can be removed from it. Powder can then be applied again to the glass plate. The component layer that has already been formed can be placed on the applied powder. By redirecting a light beam onto the processing area, the new component layer can be formed and connected to the first component layer. These steps can be repeated as often as required until the component is completely formed. The component will be manufactured from top to bottom. With this structure of the device, material can be saved, since the powder can only be deposited in the areas where a component layer is to be formed. It is then not necessary to cover the entire glass plate with powder. The glass plate has to bear significantly less weight, since the component is held by the lifting device and the glass plate only carries the powder bed for the new component layer to be formed. The already formed component layers are freely accessible and not surrounded by powder. The component can therefore be processed further during production, for example by machining the component.

The embodiments of the invention described above can, if necessary, be combined with one another. The above-described aspects of the invention are not restricted to the combinations of features of the invention that are predetermined by the selected paragraph formatting.

Further features of the present invention emerge from the following description of the invention with reference to the drawings and the drawings themselves. All of the features described and / or illustrated form the subject matter of the present invention by themselves or in any combination, regardless of how they are summarized in the claims or their interdependencies.

The invention is explained in more detail below by way of example with reference to the drawings. The drawings show schematically in:

FIG. 1 shows a process chamber of a device for the additive manufacturing of components in a lateral sectional view,

FIG. 2 shows a storage cylinder and a powder bed in a plan view with several processing heads, which can be freely arranged above the powder bed, in a plan view, FIG. 3a shows a swivel arm for positioning a processing head, a beam guide being formed from a light guide which extends from a light source to the processing head,

FIG. 3b shows a further swivel arm which has a light source at its free end in the side view,

FIG. 3c shows a further swivel arm in which a beam guide is designed as a light guide, which extends from the light source to the swivel joint of the swivel arm, with a beam guide designed by means of reflector elements being provided along the swivel arm, in a schematic, lateral sectional view,

FIG. 3d shows a further swivel arm with a pumped laser, the light pump and resonator being arranged spatially separated in a side view,

Figure 3e shows a further swivel arm in which a beam guide is designed as a light guide, which extends from the light source to the swivel arm and its end remote from the light source is arranged parallel to the swivel arm and points to the free end of the swivel arm 18, with the free end of the Swivel arm a reflector element for deflecting the light beam is seen in front of, in a schematic, lateral sectional view,

FIG. 4 shows a second embodiment of a process chamber of a device for the generative production of components in a lateral sectional view,

FIG. 5 shows a swivel arm for positioning a machining head with sensors for detecting the spatial position of the machining head in a side view,

FIG. 6 shows a sequence for setting the spatial position of the machining head shown in FIG

FIG. 7 shows a processing table with a glass plate and several processing heads, which can be freely arranged below the glass plate, in a side sectional view.

An exemplary embodiment of a device for the generative production of components, which is briefly referred to as "3D printer" 1 in the present case, is explained below Storage cylinder 4 is located (FIG. 1, FIG. 2). In the storage cylinder 4, a storage piston 5 is arranged, which can be raised or lowered vertically by means of a first floating piston / cylinder unit 6. The powder bed 3 is likewise formed from a cylindrical body and approximately rectangular in plan view, in which a production piston 7 is mounted so as to be vertically displaceable and which can be actuated by means of a second reciprocating piston / cylinder unit 8. The powder bed forms a processing area in which a 3D component 31 can be produced.

The storage cylinder 4 and the powder bed 3 are located in the process chamber 2. The powder bed 3 is arranged adjacent to the storage cylinder 4. A doctor blade 9 is provided which can be moved in the direction of movement 10 (FIG. 1) in such a way that a powder 11 held therein can be spread into the powder bed 3 from the supply cylinder 4. With the doctor blade 9, a superficial powder layer of the storage cylinder 4 is thus transferred to the upper surface in the powder bed 3. By gradually raising the storage piston 5 and gradually lowering the production piston 7, the surface of the powder 11 in the powder bed 3 and in the storage cylinder 4 can be kept at approximately the same level.

In the area above the powder bed 3, a movement device 12 for moving a plurality of processing heads 13 is provided.

The movement device 12 comprises a plurality of cross members 14 which extend transversely over the powder bed 3. The traverses 14 are arranged parallel to one another. In the present embodiment, three cross members 14 are provided (Figure 1, Figure 2). The middle Tr verse 14 is arranged slightly higher than the two outer traverses 14.

The traverses 14 have an approximately rectangular cross-section, each with a rail profile 16 protruding on the vertical longitudinal side surfaces 15, which extend over the entire length of the traverse 14 (Fig. 3a-3e). On the rail profiles 16 each of the traverse 14 two carriages 17 are mounted in the longitudinal direction of the traverses 14 displaceable Lich. The carriages 17 can be moved automatically along the respective traverse 14 by means of a drive device. The drive device can comprise a drive belt which is driven by an external motor and which is coupled to the respective carriage 17. However, a drive mechanism, such as a drive wheel driven by a motor, can also be provided in the carriage 17 itself. In principle, it is also possible to drive the slide by means of a linear motor, in which case the corresponding drive means and counter-drive means are to be provided on the slide 17 and on the traverse 14. A swivel arm 18 is arranged on the slide 17 by means of a swivel joint 19. The swivel arm 18 is rotatably supported by the swivel joint 19 about a vertical swivel axis 20. A stepping motor (not shown) for rotating the swivel arm 18 about the swivel axis 20 is provided on the slide 17. At the end of the swivel arm 18 remote from the swivel axis 20, the machining head 13 is provided, which in the exemplary embodiment shown in FIG. The processing head 13 is arranged in such a way that a light beam 24 guided in the light guide is emitted vertically downwards.

The light guide is formed from a flexible optical fiber. The optical fiber can be, for example, a glass fiber or an optical polymer fiber.

The stepper motor and the pivot joint 19 are net angeord very close to the pivot axis. As a result, the essential mass of the parts rotatable with the swivel arm 18 is concentrated around the swivel axis 20. The pivot arm 18 itself is comparatively light, so that the moment of inertia of rotation is low and the pivot arm 18 can be rotated quickly and precisely about the pivot axis 20.

The light guide 21 leads to a light source 25 which is arranged a little away from the pivot arm 18. The light source 25 is preferably a laser, in particular a CO2 laser or an ND: YAG laser or a fiber laser. The light source 25 can also be a semiconductor laser or a light-emitting diode, in particular a super-luminescence light-emitting diode.

An array of light sources 25 can also be provided, which has a light source 25 for each processing head 13.

Further embodiments of the swivel arm are explained below, which are designed in exactly the same way as the embodiment described above with reference to FIG. 3a, unless otherwise specified.

In an alternative embodiment of the swivel arm 18 (FIG. 3b), the light source 25 together with the optical lens 23 is arranged directly at the end of the swivel arm 18 remote from the swivel axis 20 such that a light beam 24 can be emitted vertically downwards. Otherwise, the swivel arm 18 is designed in exactly the same way as in the embodiment according to FIG. 3a explained above. According to a further embodiment (FIG. 3c), a beam guide is from the light source

25 up to the slide 17 by means of a light guide 26 and along the pivot arm 18 by means of reflector elements 27, 28. In the present embodiment, the reflector elements 27, 28 are each designed as a mirror. However, they can also be represented by other optical elements that deflect a light beam, such as prisms or the like.

The pivot arm 18 is designed as a hollow plastic tube, which can in particular consist of a fiber-reinforced plastic. Such a plastic pipe is very light and stiff.

The swivel joint 19 has a vertically extending through opening or through hole 29. Adjacent above the through hole 29, the end of the light guide 26 remote from the light source 25 is arranged together with a coupling lens 30, so that the light beam generated by the light source 25 is transmitted via the light guide 26 and from there coupled into the through hole 29 of the swivel joint 19 . A first reflector element 27 is arranged below the through hole 29 and deflects the light beam 24 in such a way that the light beam 24 is directed in the direction of the free end of the pivot arm 18. At the free end of the pivot arm 18 remote from the pivot axis 20, the second reflector element 28 is arranged, which deflects the light beam 24 vertically downwards. Optionally, an optical lens 30 for bundling the light beam can be provided in the beam path between the end of the light guide 26, which is arranged adjacent to the pivot joint 19, and the second reflecting element 28. Instead of the optical lens 30, an objective can also be provided with which the degree of focusing of the light beam can be changed.

The first and / or second reflector element 27, 28 can be shaped in such a way, for example as a parabolic mirror or free-form mirror, so that it bundles the reflected light. As a result, it is not necessary to arrange an optical lens in the beam path, or an optical lens with a low refractive power can be provided in the beam path.

When the machining head 13 is moved by means of the swivel arm 18, the light guide

26 is only moved along the cross member 14 with its end arranged in the slide 17. The swivel arm 18 can execute a rotary movement which has no influence on the position of the light guide 26. This makes it possible for the swivel arm 18 to perform one or more complete rotations without affecting the functionality of the Light guide 26 is impaired because it is not taken along with such a rotary movement of the pivot arm 18.

With such an arrangement one can thus provide a plurality of machining heads 13 each Weil by means of a swivel arm on a slide 17 which can be moved along the crossbars 14, whereby it is ensured that the individual light guides 26 cannot get tangled with one another. This makes it easy to create a 3D printer 1 which has at least eight, preferably at least twelve, and in particular at least sixteen processing heads, all of which can be acted upon by a light beam 24 at the same time or virtually simultaneously.

The light sources 25 can generate the light beam in continuous operation (cw) or in pulsed operation (pw). In the case of a pulsed light source 25 with a high light intensity, it can also be useful to assign a light source 25 to several processing heads 13, a multiplexer then being arranged between the light source 25 and the respective processing heads 13 so that the multiplexer generated by the light source Light beam is clearly fed to one of the plurality of processing heads 13. The change between the individual processing heads 13 can take place so quickly that the change is so fast compared to the melting or sintering process that the individual processing heads 13 coupled to it can be viewed as being impacted almost simultaneously with a bundle of light beams 24.

Another embodiment of the swivel arm (FIG. 3d) has as a light source a pumped laser with a light pump 32 and a resonator 33, which are connected to one another via a light guide 34. The resonator comprises an active medium, which preferably consists of a solid body and which is excited or pumped by means of pump light 35 emitted by the light pump 32.

The resonator 33 is arranged together with the optical lens 23 directly at the end of the pivot arm 18 remote from the pivot axis 20 in such a way that a light beam 24 can be emitted vertically downwards. The light pump 32 is arranged on the slide 17 in such a way that it does not take part in the pivoting movement of the pivot arm. The light pump 32 usually comprises one or more semiconductor lasers and a heat sink with cooling fins. The light pump is much heavier than the resonator 33 and the optical lens 23. Since only the resonator 33 and the optical lens 23 and not the light pump 32 are moved, the rotational inertia of the swing arm 18 is ge ring. In this embodiment, the light pump 32 is arranged on the slide 17. The light pump 32 can, however, also be arranged independently or remotely from the carriage 17.

This embodiment can also be modified in such a way that instead of the light guide 34, a beam guide with reflector elements is provided, as shown in FIG. 3c. Then the light guide 34 can either be omitted completely or only be guided as far as the slide 17 if the light pump is arranged at a distance from the slide 17.

An ND: YAG laser is preferably used as the pumped laser and one or more laser diodes with a wavelength of 808 nm are used as the light pump. However, another laser, such as a Yb: YAG laser, can also be provided.

According to a further embodiment (FIG. 3 e), a beam guide is formed from the light source 25 to the pivot arm 18 by means of a light guide 26. The light guide 26 is guided from the light source 25 to the swivel arm 18, the light guide 26 with its end remote from the light source 25 being arranged below the swivel arm 18 in the region of the slide 17. The light guide 26 is connected to the swivel arm 18 in such a way that the light guide 26 is guided along the swivel arm in the region of the slide 17 and its end remote from the light source 25 points to the free end of the swivel arm 18. At the free end of the pivot arm 18, a reflector element 28 is arranged, which is designed as a mirror. The reflector element 28 can, however, also be represented by other means of deflecting a light beam 24 of the optical element, such as a prism or the like, for example.

A light beam 24 emitted by the light source 25 is transmitted by the light guide 26 and emitted at its end remote from the light source 25 such that the light beam 24 is directed along the pivot arm 18 in the direction of the reflector element 28, preferably parallel to the pivot arm. At the free end of the swivel arm 18, the second reflector element 28 is arranged, which deflects the light beam 24 downwards onto the processing area. Optionally, an optical lens 30 for bundling the light beam 24 can be provided in the beam path between the end of the light guide 26 and the reflector element 28. Instead of the optical lens 30, an objective can also be provided in order to be able to change the degree of bundling of the light beam 24 and / or the reflector element 28 can be designed to be correspondingly curved.

When the machining head 13 is moved by means of the swivel arm 18, only the end of the light guide 26 remote from the light source 25 is carried along. The swivel arm 18 can be made particularly light in this embodiment, since only small loads have to be absorbed. A correspondingly designed swivel arm 18 has only a low rotational moment of inertia, so that it can be swiveled quickly to any rotational position. The movement of the slide 17 can also take place particularly quickly due to the low weight of the pivot arm 18.

With such an arrangement, a plurality of processing heads 13 can be provided, each by means of a swivel arm 18, on a slide 17 that can be moved along the crossbars 14, whereby it is ensured that the individual light guides 26 cannot get tangled with one another. This makes it easy to create a 3D printer 1 which has at least eight, preferably at least twelve, and in particular at least sixteen processing heads 13, all of which can be acted upon by a bundle of light rays 24 at the same time or virtually at the same time.

In the present embodiment, the traverses 14 and thus also the pivot arms 18 attached to them are arranged at different levels (FIG. 1: middle traverse higher than the lateral traverses), so that the pivot arms 18, which are arranged on the central traverse 14, do not can collide with the pivot arms 18 which are arranged on the outer cross members 14. The level of the pivot arms 18 can also be designed differently if all the crossbars are arranged at the same height. This can be accomplished, for example, in that the swivel joints 19 are attached to the individual carriage 17 at different heights.

In the exemplary embodiment explained above, the cross members 14 are arranged in a stationary manner. In the context of the invention, however, it is possible that the traverses can be moved horizontally and transversely to their longitudinal direction. Such a configuration of the movement device 12, however, requires a more complex control so that the individual pivot arms 18 do not collide. The arrangement with stationary cross members 14 is therefore generally preferred. Such a configuration of the movement device 12 allows the 3D printer to be easily scaled, for example by attaching additional carriages to the existing crossbars or by attaching one or more additional crossbars in order to increase the production speed.

In the embodiment explained above, the pivot arms 18 are not adjustable in the vertical direction Rich. In the context of the invention, however, it is possible either to provide a device for adjusting the vertical position of the swivel arm 18 on the slide 17 o- to train the crossbars 14 and / or the entire movement device 12 in the vertical posi tion adjustable. This can be particularly useful in order to create sufficient space for the movement of the squeegee between the powder bed 3 and the swivel arms 18 when wiping the powder bed 3 by means of the squeegee 9 and after the squeegee 9 is located outside the area of the powder bed 3 the pivot arms 18 are lowered in order to be as close as possible to the surface of the powder in the powder bed 3 with the processing heads 13.

The light sources 25 for the individual processing heads 13 can be designed identically and each generate a light beam with the same intensity and the same frequency or the same frequency range. In the context of the invention, however, it is also possible, please include to provide different light sources for the different processing heads, with which light with different frequencies or frequency ranges is emitted and / or with different intensities. Light sources can also be provided with which the wavelength of the light can be tuned over a certain range. Such lasers, which can be tuned in frequency, are known and generally have a semiconductor amplifier.

An advantage of the present invention is that at the same time, through the multiple processing heads 13, different points of the powder 11 located in the powder bed 3 can be exposed to light and thus heat and can be melted or sintered at the same time. As a result, the manufacturing process is parallelized and significantly accelerated compared to conventional 3D printers. A 3D component 31 (FIG. 1) can thus be generated very quickly.

The processing heads 13 can be positioned very precisely above the powder bed 3, as a result of which highly precise 3D components can be manufactured.

The movement device 12 for the processing heads 13 is very simple and can be produced much more cost-effectively compared to 3D printers with a similar performance.

A first embodiment of a second embodiment is explained below. The second exemplary embodiment, like the first exemplary embodiment, comprises a process chamber 2, a powder bed 3, a doctor blade 9 and at least one processing head 13. Identical parts of the second exemplary embodiment are denoted by the same reference symbols as in the first exemplary embodiment. The above explanations apply to the same parts, provided that they are below no other statements are made in this regard. The process chamber 2 can have a device for supplying an inert gas atmosphere in order to avoid oxidation of the powder 11 during the production of the component.

A processing table 36 with a table top 37 is provided in the process chamber 2.

The processing table 36 has temperature control channels 38 in order to control the table top 37, also called Aufla gefläche, to a desired temperature. By tempering the table top 38, stresses in the component, in particular layers in the first component, can be reduced or completely reduced or prevented.

In the process chamber 2, the processing head 13 is provided on a movement device 12 (not shown in FIG. 4) in the same way as in the first exemplary embodiment, in order to direct a light beam 24 onto the processing table 36. The processing head 13 can, however, also be arranged in a stationary manner and the light beam emitted by the processing head can be directed to any point in the powder bed 3 with a deflection device, which has, for example, two movable mirrors.

Instead of a single machining head 13, a movement device 12 with a plurality of machining heads 13 can also be provided, as is shown in FIGS. 1 to 3d.

An order dispenser 39 is provided in the process chamber, which has a storage chamber 40 for powder 11 and a closable application opening 41 through which the powder 11 can leave the storage chamber 40 for application to the processing table 36. The order dispenser 39 has a doctor blade 9 for smoothing the powder 11 applied in the powder bed 3.

The machining table 36 is surrounded by a wall 42 in the horizontal direction. The wall 42 encloses the table top 37 of the processing table 36 with little play.

The wall 42 is connected to a foundation 44 of the 3D printer 1 via a plurality of lifting cylinders 43. The lifting cylinders 43 can adjust the height of the wall 42 relative to the machining table 36 in the vertical direction. The wall 42 can thus protrude upwards a little at the side of the processing table 36 and thus delimit a cavity which forms the 3 bed powder. The machining table 36 can be connected to the foundation 44 via dampers in order to reduce or prevent the transmission of shocks and vibrations to the machining table 36. The order dispenser 39 is coupled to a movement mechanism (not shown) with which the order dispenser 39 can be moved horizontally across the processing table 36 and thus parallel to the table top 37 of the processing table 36. The movement mechanism of the order dispenser 39 is coupled to the wall 42 in such a way that the movement mechanism is raised or lowered together with the wall 42. As a result, a lower edge 45 of the doctor blade 9 is always at the level of an upper edge 46 of the wall 42.

The height adjustment of the wall 42 can be coupled to other components in the process chamber. In this way, the machining head 13 can also be moved together with the wall 42. In this way, the vertical distance between the processing table 36 and the processing head 13 or between the processing head 13 and the wall 42 remains constant for each component layer to be produced. The light beam 24 then does not have to be re-focused on the production level fo before each production of a further component layer. The process management of the component production can thereby be accelerated.

The wall 42 can be provided at its upper edge with an outwardly horizontally vorste existing collar 47, which prevents powder from falling on the foundation in areas that are not intended for this purpose. The collar 47 can only be provided on one side of the powder bed 3 or can be formed on several or even circumferentially.

A collecting device, in the form of a collecting basin 48, is arranged around the processing table 36 or around the collar 47 in order to collect excess powder 11 that is brushed off, for example, by the doctor blade 9 from the processing table 36 or collar 47.

The collecting basin 48 is attached to a suction device 49 which feeds the collected powder 11 to a filter 50. In the filter 50, particles above a certain grain size are retained, for example particles with a grain size of more than 120 μm. Corresponding particles to be filtered out can, for example, be dirt particles or powder particles that are already connected to one another. The powder material filtered in the filter 50 is then fed via a supply line 51 to the order dispenser 39 for reuse. In this way, a recirculating circuit is created, through which excess powder 11 can be reused, as a result of which material savings can be achieved.

In this embodiment, the processing table 36 can be designed to be particularly simple and therefore inexpensive, since the processing table 36 does not have to be moved. In the Additive manufacturing of components, the machining table 36 must be designed to carry high loads due to the high material density. If the processing table has, for example, a support surface of 1.5 mx 1 m and a stroke of 0.5 m, the result is a working volume of 0.75 m ³ . If this working volume is filled with aluminum powder, the contents weigh about 2 t. In the case of steel powder, the weight is about 61. The components to be moved, such as the wall 42 and possibly other components (order dispenser 39, doctor blade 9, processing head 13), are significantly lighter than a processing table 36 with a large working volume. It is therefore possible to move these components with a drive with a significantly smaller dimension, whereby the acquisition costs but also the operating costs can be reduced. At the same time, the structure of the 3D printer 1 is also simplified.

In Figure 4, the process chamber 2 is shown at the beginning of the additive manufacturing of a component. To apply the powder 11 to the processing table 36, the order dispenser 39 moves in the direction of movement 10 over the entire processing table 36. The powder 11 applied is smoothed out by the doctor blade 9. Subsequently, the first component layer can be formed by a light beam 24. After the first component layer has been produced, the wall 42 is moved upwards by the height of the first component or powder layer. The order dispenser 39, coupled with the wall 42, is moved upwards by the same height. The aforementioned steps are then repeated until the component is completely manufactured. The wall 42 forms together with the Bear processing table 36 a powder bed 3 that grows with the height.

The wall 42 can be moved depending on the thickness of the next component to be formed layer. It is possible that the component layers each have different thicknesses. Thus, during production, individual component layers can be made thicker than others if a high degree of partial accuracy is not important in the corresponding component areas. In this way, component production can be accelerated in individual component areas and thus also take place particularly quickly overall. If, on the other hand, a high degree of dimensional accuracy is important in individual component areas, the component layer to be manufactured can have a small thickness. The component can thus be manufactured particularly quickly, depending on the dimensional accuracy required in the respective areas.

According to a second embodiment of the second embodiment, the moving device 12 for the machining head (s) 13 can be mechanically decoupled from the wall 42 so that both can be moved independently of one another (FIG. 5). The machining heads 13 are each connected to a traverse 14 via a swivel arm 18, a swivel joint 19 and a slide 17. In contrast to the first exemplary embodiment, a vertical movement device is provided on the slide 17, so that the machining head is arranged to be movable in the vertical direction. In FIG. 5, only a single machining head 13 is shown for the sake of a simpler visual representation.

The processing head 13 has an optical lens 23 in order to focus the light beam 24 emitted by it onto the surface of the powder bed. In the process chamber 2, three distance sensors 52 are arranged in a stationary manner. The distance sensors 52 are designed for electro-optical distance measurement between the distance sensors 52 and the processing head 13. To measure the distance between the distance sensors 52 and the machining head 13, a reference element 53, for example a reflector, in particular a prism reflector, for optical bundles of rays 54 is arranged on the machining head 13. ,

The distance sensors 52 are stationary but pivotable in the process chamber 2 so that a respective optical beam 54 emitted by the distance sensor 52 can be tracked to the reference element 53. The distance sensors 52 are connected to a control and regulating device 55. From the three measured distances between tween the machining head 13 and the three distance sensors 52, the spatial posi tion of the machining head 13 can be determined exactly. With the help of the control and regulation device 55, the machining head 13 can be moved precisely to a desired position in three-dimensional space. The positioning of the machining head 13 is regulated via the distance measurements.

This makes it possible to decouple the movement of the processing head 13 from the movement of the wall 42 and still focus the emitted light beam 24 exactly on the surface of the powder bed.

Preferably, one or more reference elements 53 are provided on the wall 42, in particular its upper edge, which can be scanned by the distance sensors in order to determine the height of the wall 42. In this way, the relative position of the machining head (s) 13 and the wall 42 can be detected.

Instead of detecting the height of the wall 42, the height of the powder bed 3 can also be scanned with a suitable sensor. The processing heads 13 can then be aligned directly with regard to the height of the powder bed 3. The drive with which the slide 17 and the swivel joint 19 are moved is controlled by the control and regulation device 55 as a function of the current position of the machining head 13. For this purpose, the machining head 13 can be moved more slowly the closer it comes to its target position. In this way, the machining head 13 can be transferred exactly into a target position with a favorable and inherently not very exact movement device 12, the accuracy of the position being determined solely by the distance measurement by means of the distance sensors 52. In this way, the overall costs of the 3D printer 1 can be reduced, since the distance sensors 52 are inexpensive and, at the same time, a more cost-effective movement device 12 or a more cost-effective drive can be used.

The structure shown in FIG. 5 for controlling and regulating a processing head 13 can also be used to precisely position other components, for example a squeegee 9, an order dispenser 39, a wall 42 or any other movable component with the aid of a control loop.

In the second exemplary embodiment, optical distance sensors 52 are used to measure the distances between the reference elements 53 and the distance sensors 52. Such distance sensors 52 are inexpensive and have a very high resolution. You can determine the distance to the reference element 53 by means of triangulation. In the case of triangulation, an optical beam 54, for example a laser beam, is focused on the measuring object and observed with a camera located next to it in the distance sensor 52, a spatially resolving photodiode or a CCD line. If the distance between the measuring object and the sensor changes, the angle at which the point of light is observed also changes and thus the position of its image on the photo receiver. The distance between the object and the laser projector is calculated from the change in position with the aid of the angle functions. Distance measurement using triangulation is very simple and inexpensive. If the accuracy requirements are low, the radiation from a light-emitting diode can also be used as a light beam.

The distance can also be measured by measuring the phase position. When measuring the phase position, an optical beam 54, for example a laser beam, is emitted. The phase shift of the reflected laser beam compared to the emitted beam is distance-dependent. This phase shift can be measured and used to determine the distance traveled. The distance measurement by measuring the phase position has a high degree of accuracy. When measuring the distance over the transit time, a brief light pulse, a constant light beam or a light modulation is emitted. The pulse transit time is the time it takes for the light beam to travel from the source to a reflector and back to the source. By measuring this transit time, the distance between the source and the object can be determined using the speed of light.

For distance measurement it is also possible to use sensors that scan lines or areas or planes, such as stereo cameras for three-dimensional localization of one or more objects. Corresponding sensors do not have to be designed to be pivotable due to their large recording area.

The aforementioned distance sensors 52 are manufactured and sold by the company Micro-Epsilon, for example.

Regardless of the type of sensors, the advantage is that the position of the processing heads can be set very precisely due to the control loop. This can also be used to determine the position of the machining heads, which can only be moved in one plane, according to the first exemplary embodiment.

For precise positioning, the actual position of the movable component, for example the machining head 13, can be detected after the start (FIG. 6). Flierzu the stand between the machining head 13 and the respective distance sensor 52 can be measured. The actual position is detected by a distance measurement with the aid of the distance sensors 52 from FIG. 5. The actual position of the machining head can be determined in a simple manner from the three distance measurements. If the actual position corresponds to the target position, no further action is required and component production can be continued.

The position of the movable component, for example the machining head 13, can be determined absolutely in space. However, the position of the movable component can also be determined relative to another component. In the latter case, the distance between the two components is determined. The actual position of the movable component can be regulated in any spatial direction or in relation to each axis individually and one after the other until the target position is reached. However, it is also possible to regulate the position of the movable component in all three spatial directions or with respect to all axes at the same time.

The distance sensors 52 can be arranged in a stationary manner in the process chamber 2 of the 3D printer 1; for example, the distance sensors 52 can be connected to the foundation 44 of the 3D printer 1 via a carrier. The distance sensors 52 can determine the position of the surface of the powder bed 3 via a distance measurement and then determine the position of a movable component, for example a machining head 13, with the aid of a further distance measurement. The processing head 13 can be moved into a target position depending on the position of the powder bed 3, i.e. the height of the powder bed 3, in order to set a required distance between the processing head 13 and the surface of the powder bed 3. One or more machining heads 13 can be moved into their desired position with the aid of the control and regulating device 55 described above. It is also possible that one or more distance sensors 52 are connected to a processing head 13 or are arranged on this and the distance between the processing head 13 and the powder bed surface is determined directly in order to then set the processing heads 13 to a target distance from the surface of the To move powder beds 3.

If the actual position does not correspond to the target position, the position of the processing head 13 is then modified. For this purpose, a drive can be started and the Verfahrgeschwin speed of the machining head 13 can be set as a function of the distance between the actual position and the target position. The smaller the distance between the actual position and the target position, the lower the travel speed that can be selected. After a defined time unit and / or a defined distance covered, the actual position can be recorded again and then modified if necessary. It is also possible to record the actual position continuously. In this way a closed control loop can be created. This regulation makes it possible to transfer the machining head 13 exactly into a desired position with a simple, inexpensive and inherently not very exact movement device 12. The accuracy of the positioning is determined solely by the distance measurement by means of the distance sensors 52.

In addition, it is also possible for the position of the machining heads 13 to be set as a function of the position of the movable wall 42, in particular an upper edge and / or a horizontal surface. At least one distance sensor can be used for this purpose 52 connected to the processing heads 13 or arranged in a stationary manner in the 3D printer 1.

Instead of the position of one or more machining heads 13, the position of a cross member 14 or another component of a direction of movement 12, for example a slide 17, can be determined and positioned relative to the movable wall 42 or the surface of the powder bed 3. For this purpose, the cross member 14 can have one or more distance sensors 52 and measure the distance to the surface of the powder bed 3.

In the same way, a doctor blade 9 can also be positioned relative to the powder bed surface or a movable wall 42. One or more distance sensors 52 can then be connected to the doctor blade 9 and / or arranged in a stationary manner in the process chamber 2.

It is also possible to position an order dispenser 39 as a function of the position of the movable wall 42 or the surface of the powder bed 3. For this purpose, the order dispenser 39 can have at least one distance sensor 52 and / or at least one distance sensor 52 can be arranged in a stationary manner in the process chamber 2 of the 3D printer 1.

The movable wall 42 can also be moved relative to the surface of the powder bed 3, for example to a position that is one layer thickness higher than the powder bed 3. For this purpose, it is advantageous if the distance sensors 52 are arranged in a stationary manner in the process chamber 2 and determine the distance between the movable wall 42 and the surface of the powder bed 3.

In addition, it is also possible to move a storage cylinder 4 relative to a processing table. In known 3D printers 1, the processing table 36, formed as a production piston 7, can also be moved in a controlled manner. For example, after the completion of a component layer, the production piston can be lowered by a defined layer thickness in order to be able to apply a new powder layer. The distance sensors 52 are then preferably arranged in a stationary manner in the process chamber 2 of the 3D printer 1.

Several moving components can also be coupled together. For example, a doctor blade 9 together with one or more processing heads 13 and / or together with an order dispenser 39 can be regulated at a distance from the surface of the powder bed 3 that is necessary in the vertical direction be positioned. The vertical distance between the doctor blade 9 and the processing heads 13 and / or the order dispenser 39 is then the same at all times.

Another embodiment of a third embodiment is explained below. The same parts in the third exemplary embodiment are denoted by the same reference numerals as in the first and second exemplary embodiments. The above explanations apply to the same parts, unless otherwise stated below.

In the process chamber 2, a glass plate 56 is arranged horizontally as a table top 37 of the processing table 36. A movement device 12 for moving a plurality of processing heads 13 is provided below the glass plate 56.

The movement device 12 comprises three cross members 14 which extend below the glass plate 56 transversely. The traverses 14 are arranged parallel to one another. In the present embodiment, the middle cross member 14 is slightly lower than the two äuße Ren cross members 14 are arranged.

As described in FIGS. 1 and 2, the movement device 12 has two carriages 17, each with a swivel arm 18, on each traverse 14. At least one machining head 13 is arranged on each of the pivot arms 18. The pivot arm 18 can be designed as in Figures 3a-3d.

In the process chamber 2, a support body 57 is arranged above the glass plate, on the sen underside 58 of which the component is manufactured. The first component layer is formed on the underside 58 and can be connected to the support body 57. The support body 57 can be moved or adjusted together with the component 31 in the vertical direction of movement 59. For this purpose, a lifting device 60 can be provided for gripping and lifting the component 31.

For the generative production of a 3D component 31, powder 11 can only be deposited on the entire glass plate 56 by an order dispenser 39 (not shown in FIG. 6). The glass plate 53 serves as a support surface for the powder 11. The powder can be smoothed out by a doctor blade 9, not shown in FIG. 6, whereby a powder layer 61 is formed. The support body 57 is then placed on the powder 11. The powder 11 is then emitted by the processing heads 13 with the aid of the light beam bundles 24 selectively melted or sintered and bonded to form a component layer. The component layer can then be connected to the support body. The component layer is then raised together with the support body 57. The lifting device 60 can be used to support gripping and lifting of the component layer. The unused powder 11 can then be removed from the glass plate 56 in order to prevent individual powder grains connected to one another from being used in the production of the next component layer. The order dispenser 39 can then again place powder 11 on the glass plate and a new powder layer 61 can be formed. The component is then placed on the new powder layer 61. The powder material is melted or sintered, whereby a new component layer is formed, which is connected to the previous component layer at the same time. The aforementioned steps are repeated until the component 31 is completely manufactured. The component 31 is manufactured in this way from top to bottom.

Reference list

1 3D printer 35 32 light pump

2 process chamber 33 resonator

3 powder bed 34 light guides

4 storage cylinder 35 pump light

5 storage piston 36 machining table

6 reciprocating piston / cylinder unit 40 37 table top

7 production piston 38 temperature control channel

8 reciprocating piston / cylinder unit 39 order dispenser

9 squeegee 40 storage chamber

10 Direction of movement 41 Order opening

11 powder 45 42 wall

12 movement device 43 lifting cylinder

13 Processing head 44 Foundation

14 Traverse 45 lower edge

15 long side surface 46 edge

16 rail profile 50 47 collar

17 sledges 48 reservoirs

18 Swivel arm 49 Extraction

19 swivel joint 50 filters

20 swivel axis 51 supply line

21 light guide 55 52 distance sensor

22 end 53 reference element

23 Optical lens 54 Beam bundle

24 light beam 55 control and regulation device

25 light source 56 glass plate

26 light guide 60 57 support body

27 reflector element 58 underside

28 Reflector element 59 Direction of movement

29 through opening 60 lifting device

30 Optical lens 61 powder layer

31 3D component 65

Claims

1. Device for the generative production of components, in particular by means of selective melting or sintering, with a light source (25) for generating a light beam (24), a processing head (13) which is either coupled to the light source (25) with a beam guide, so that the light beam (24) leads to the processing head (13) ge, or the light source (25) is arranged directly on the processing head (13) so that a light beam (24) can be directed from the processing head (13) to a processing area , wherein the processing head (13) is movably mounted so that the light beam (24) can be directed to different locations in the processing area, and several processing heads (13) are provided for each directing a light beam (24) onto the processing area, and the Machining heads are each arranged on a slide (17) which can be moved along a traverse (14), the Bear processing heads (13) are each arranged on one of the carriages (17) by means of a swivel arm (18) which can be swiveled about a vertical swivel axis (20).

2. Device according to claim 1, characterized in that the pivot arms are designed with a length of at least 5 cm.

3. Apparatus according to claim 1 or 2, characterized in that at least along the pivot arms (18) the beam guide for the respective light beam (24) is formed by means of reflector elements (27, 28).

4. Device according to one of claims 1 to 3, characterized in that the pivot arms (18) are made of plastic, in particular fiber-reinforced plastic, and / or are removed on each of a pivot axis (20) At the end a reflector element (28) is provided for directing the respective light beam (24) onto the processing area.

5. Device according to one of claims 1 to 4, characterized in that one of the light sources (25) or one resonator (33) each as a light source ( 25) serving laser are arranged.

6. Device according to one of claims 1 to 5, characterized in that several beam guides are provided and at least partially designed as light guides (21, 26).

7. Device according to one of claims 1 to 6, characterized in that a plurality of cross members (14) arranged parallel to one another and in one plane are provided.

8. Apparatus according to claim 7, characterized in that the cross members (14) are arranged in a stationary manner.

9. Device according to one of claims 1 to 8, characterized in that at least two independently movable carriages (17) are mounted on each traverse (14), each carriage (17) having a processing head (13).

10. Device according to one of claims 1 to 9, characterized in that several light sources (25), in particular an array of light-emitting diodes and / or semiconductor lasers, are provided, each light source (25) being assigned to one or more processing heads (13) .

11. Device according to one of claims 1 to 10, characterized in that that a multiplexer is provided for distributing the light beam from one of the light sources (25) to different beam guides which each lead to one of the processing heads (13).

12. Device according to one of claims 1 to 11, characterized in that a control device is provided which is designed such that several processing heads (13) can be moved simultaneously and / or can be acted upon by a light beam (24) at the same time.

13. Device according to one of claims 1 to 12, characterized in that a powder bed (3) is provided which forms the processing area.

14. Device for the generative production of components, in particular by means of selective melting or sintering, preferably according to one of claims 1 to 13, with a loading work table (36) with a preferably horizontal table top (37) which has a support surface for a powder bed (3 ), wherein the processing table (36) has a wall (42) which at least partially laterally delimits the table top (37), and where the table top (37) and the wall (42) jointly define the processing area, characterized in that the wall (42) is preferably movable perpendicular to the table top (37).

15. The device according to claim 14, characterized in that the wall (42) can be moved together with at least one further component, preferably a light source (25) and / or a processing head (13) and / or a doctor blade (9) and / o an order dispenser (39) and / or a storage cylinder (4).

16. Device according to one of claims 1 to 15, characterized in that an order dispenser (39) is provided for applying powder (11) to be selectively melted or sintered onto the table top (37).

17. Device according to one of claims 1 to 16, characterized in that a collecting device is provided, preferably designed as a collecting basin (48) in order to receive excess powder (11) that has come out of the processing area.

Device according to claim 17, characterized in that a suction device (49) and a filter (50) are provided in order to be able to suction off, filter and reuse the excess powder.

19. Device for the generative production of components, in particular by means of selective melting or sintering, preferably according to one of claims 1 to 18, with at least one movable component, preferably a processing head (13) and / or a processing table (36) and / or a wall (42) and / or a doctor blade (9) and / or an order dispenser (39), and a drive for moving the movable component, characterized in that at least one distance sensor (52) is provided for preferably electro-optical distance measurement.

20. The device according to claim 19, characterized in that the distance sensor (52) is arranged stationary in order to measure the distance between the distance sensor (52) and the moving component.

21. The device according to claim 19 or 20, characterized in that a control and regulating device (55) is provided, which is designed such that the moveable component as a function of the measured distance between the distance sensor (52) and the moveable Component can be moved into a target position.

22. Device according to one of claims 19 to 21, characterized in that two, preferably three distance sensors (52) for distance measurement between the stand sensors (52) and the movable component are provided in order to determine the spatial position of the movable component.

23. Device according to one of claims 19 to 22, characterized in that at least three distance sensors (52) and at least two movable components are provided, each component being detectable in every position by at least three distance sensors (52) for distance measurement.

24. Device according to one of claims 19 to 22, characterized in that three distance sensors (52) are permanently assigned to each movable component for distance measurement.

25. Device for the generative production of components, in particular by means of selective melting or sintering, preferably according to one of claims 1 to 13, with a Glass plate (56), the surface of which forms a support surface for powder (11), a processing area above the glass plate (56), a light source (25) for generating a light beam (24), a processing head (56) arranged below the glass plate (56) 13), which is either coupled to the light source (25) with a beam guide so that the light beam (24) is guided to the processing head (13), or the

The light source (25) is arranged directly on the processing head (13) so that a light beam (24) can be directed from the processing head (13) through the glass plate (56) to the processing area, the processing head (13) being movably mounted, so that the light beam (24) can be directed to different points in the processing area, characterized in that several processing heads

(13) are provided for directing a bundle of light rays (24) through the glass plate (53) onto the processing area, the processing heads (13) each being arranged on a slide (17) which can be moved along a cross-member (14).