DE102017215268A1 - Method for laser deposition welding - Google Patents

Abstract

In the method for additive production of a component (WER) by means of laser deposition welding, the component is produced at the same time by means of at least two or more robots (ROB1, ROB2) respectively designed for laser deposition welding.

Description

The invention relates to a method for laser deposition welding and a laser deposition welding machine.

In the field of additive manufacturing, it is known to produce a workpiece generatively by laser deposition welding.

For this purpose, a design model of the workpiece is regularly used, which is created by CAD (CAD = "Computer Aided Design") and is available in digital form. This design model includes i.a. the geometric shape of the workpiece as a surface or solid.

For the preparation of laser deposition welding (LMD = Laser Metal Deposition) itself, the geometric shape of the workpiece is subdivided into individual planes whose spacing is determined by the build-up height of the laser deposition welding process. This process is regularly supported by CAM (CAM = Computer Aided Manufacturing). By means of CAM, depending on the parameters decisive for the laser deposition welding process, points are determined for each individual plane at which the geometric shape of the workpiece intersects the plane. In contrast, at locations where the contour intersecting the plane is filled, additional points corresponding to a fill pattern are provided within the contour. As far as in the context of the present invention of laser deposition welding is mentioned, this is synonymous with LMD to understand.

A multi-axis system or a machine tool or a robot drives these points along a trajectory or travel path connecting these points and melts a metal powder supplied through a nozzle along this travel path with a laser. The molten metal powder is deposited on the deeper parts already processed part of the workpiece, where the metal solidifies quickly. The point at which the multi-axis system or the machine tool or the robot deposits the metal is also referred to in the context of the present application as a spatial operating point or tool center point (TCP).

Although complex workpiece geometries can be realized in additive manufacturing by means of laser deposition welding, there are still some limitations in this method: the size of a workpiece to be manufactured is limited by the working space of the multi-axis system, the machine tool or the robot. Furthermore, fabrication by laser deposition welding requires a considerable amount of time.

It is therefore an object of the invention to provide an improved process for additive production by means of laser deposition welding, by means of which, in particular, fundamentally arbitrarily large workpieces can be produced. It is another object of the invention to provide an improved manufacturing device for additive manufacturing by laser deposition welding, by means of which in particular arbitrarily large workpieces can be manufactured. In particular, should be possible with the method according to the invention and by means of the manufacturing device according to the invention a more rapid additive manufacturing.

This object of the invention is achieved with a method for additive production by laser deposition welding with the features specified in claim 1 and with a manufacturing device for additive production by means of laser deposition welding with the features specified in claim 10. Preferred embodiments of the invention will become apparent from the accompanying dependent claims, the following description and the drawings.

The method according to the invention is a method for the additive production of a component by laser deposition welding, in which the component is produced at the same time by means of at least two or more robots each designed for laser deposition welding. As far as in the context of the present application of "component" is mentioned, this term is synonymous with "workpiece" used.

The use of several robots in the additive manufacturing of components advantageously allows for the one hand, the production of components with larger dimensions and on the other hand, the reduction of manufacturing time: In particular, components are not in terms of their size as usual in the art on the working space of a production machine, such as one single robot, limited. Depending on requirements, several and in principle any number of robots can be arranged for laser deposition welding instead. In addition, according to the invention, a significantly greater build-up rate is possible by means of the use of several robots.

Advantageously, in the method according to the invention, the component is produced in successive layers, each layer being produced at the same time by means of the at least two robots. In principle, the method according to the invention fits into the established procedures in additive manufacturing, in particular in the layered structure.

In the method according to the invention, a quantity of laser deposition welding points, in particular one, is expediently Laser deposition welding trajectory, intended for the production of the component. In this development, each laser deposition spot of this quantity is allocated to one, in particular exclusively one, specific robot in this development of the invention.

Suitably, in the method according to the invention, each of the robots is assigned a working space within which the robot can laser-weld laser deposition welds. Suitably, the working space is defined by, for example, a range of a robotic arm supporting a laser and a powder nozzle of the robot.

In a preferred development of the method according to the invention, each of the robots has a spatial operating point, wherein each of the robots is assigned an exclusivity environment around this operating point, wherein no robot is assigned a laser deposition weld point within the exclusivity environment of another of the robots. Such an exclusivity environment is used to block an area around the TCP (ie the spatial operating point) of a robot for the entry of other robots in order to avoid collisions and too narrow processing distances.

In the method according to the invention, each of the robots is preferably assigned an initial laser deposition weld point.

Suitably, in the method according to the invention, each of the robots is assigned, starting from a respectively assigned laser deposition weld point, such a sufficiently small or as little as possible spaced succeeding laser deposition weld point, which is arranged within the working space of the robot and not already assigned to one of the robots and not within the exclusivity environment one of the other robots is arranged. Expediently, the laser deposition welding point which is as closely spaced as possible is in fact the next adjacent laser deposition spot.

Preferably, in the method according to the invention, it is checked for each of the robots for an associated subsequent laser deposition weld spot whether the robot has to start anew for laser deposition welding at the subsequent laser deposition weld point. Such attachment (such as the laser or the nozzle or an articulated arm of the robot) causes delays in the manufacturing process and should be avoided if possible. The method according to the invention expediently keeps the undesired process of reassembly.

In an advantageous development of the invention, in the method, the amount of laser deposition welds of at least one layer or the entire component is assigned to robots in such a way that as rare a robot for laser deposition welding at the subsequent laser deposition weld has to start again. Ideally, a quality criterion is used for the rare new start of the robot. Expediently, such a quality criterion is the frequency of the requirement of a robot to start new laser deposition welding at the subsequent laser deposition weld point. Advantageously, one or more parameters are / are varied in the method, so that an assignment of laser deposition welding points to robots can be made on the basis of the quality criterion, suitably such that the new preparation is minimized as far as possible in its frequency. Preferably, the initial laser deposition welds form such a parameter.

The production device according to the invention for additive production by laser deposition welding has at least two or more robots. The manufacturing device is designed to carry out the method and in particular has a control unit which is designed to carry out the method.

Suitably, in the manufacturing device according to the invention, the robots and / or the control unit are signal-connected to one another.

As a result of the signal connection of the control unit and / or robots, the robots can synchronously synchronize with each other. In particular, it can be ensured by means of the signal connection that the method is interrupted in the event of a fault of one of the robots.

The invention will be explained in more detail with reference to embodiments shown in the drawing.

• 1 den Ablauf eines Ausführungsbeispiels eines erfindungsgemäßen Verfahrens zur additiven Fertigung durchgeführt mittels eines Ausführungsbeispiels einer erfindungsgemäßen Fertigungseinrichtung zur additiven Fertigung mittels Laserauftragsschweißens schematisch in einer diagrammatischen Darstellung,
• 2 die Fertigungseinrichtung bei der Durchführung des erfindungsgemäßen Verfahrens gem. 1 schematisch in einer perspektivischen Darstellung,
• 3 einen Verfahrensschritt des erfindungsgemäßen Verfahrens gem. 1 zur Zuordnung von Schweißpunkten zu einem Roboter der erfindungsgemäßen Fertigungseinrichtung schematisch in einer diagrammatischen Darstellung sowie
• 4 eine mittels des erfindungsgemäßen Verfahrens erfolgte Zuordnung von Schweißpunkten zu zwei Robotern der erfindungsgemäßen Fertigungseinrichtung schematisch in einer Draufsicht.

Show it:

• 1 the sequence of an embodiment of a method according to the invention for additive manufacturing carried out schematically by means of an embodiment of a manufacturing device according to the invention for additive manufacturing by laser deposition welding in a diagrammatic representation,
• 2 the manufacturing device in the implementation of the method according to the invention. 1 schematically in a perspective view,
• 3 a process step of the method according to the invention. 1 for assignment from welding points to a robot of the manufacturing device according to the invention schematically in a diagrammatic representation and
• 4 an allocation of welding points to two robots of the production device according to the invention, carried out by means of the method according to the invention, schematically in a plan view.

This in 1 illustrated inventive method for additive manufacturing by laser deposition welding is by means of a manufacturing device according to the invention ( 2 ) for additive manufacturing of a workpiece.

This is done first in a first step PCAD a CAD model of a workpiece WHO used. The CAD model contains the complete spatial geometry of the workpiece to be machined WHO ,

In a second process step PCAM is the spatial geometry of the CAD model of the workpiece WER means CAM in levels numbered from 1 to k and further to n L divided. This is done in advance by means of CAM the orientation of the workpiece WHO optimized relative to these planes such that the workpiece WHO is efficient to manufacture. In this process step, those points are then along which the workpiece is laser-deposited by welding WHO to be welded.

In a subsequent process step PALG becomes the workpiece WHO along these levels by means of two robots Rob1 . rob2 made ( 1 and 2 ). In further, not specifically illustrated embodiments, instead of two robots Rob1 . rob2 In principle, more than two robots, for example three or four robots, for the production of the workpiece WHO Find employment.

Each of the robots Rob1 . rob2 has a workspace WOSP1 . WOSP2 within, within which the robot Rob1 . rob2 at the points by means of its respective spatial operating point TCP1 . TCP2 laser deposition welding can. The workrooms WOSP1 . WOSP2 expediently overlap at least partially at the location of the workpiece WHO , Furthermore, the robots point Rob1 . rob2 According to the invention, in each case one process area PB1 . PB2 on, which for each other the robot Rob1 . rob2 is considered locked, to collisions and too narrow processing distances between the spatial operating points TCP1 . TCP2 to avoid.

For the production of the workpiece WHO is in the process step PALG First determine which points of which of the robots Rob1 . rob2 to be welded:

First of all, for each one of the robots Rob1 . rob2 proceed as follows (s. 3 ):

The robot has a spatial operating point or TCP on which the robot deposits metal by laser deposition welding. This TCP is determined by the method step IP to a first point at which the workpiece is to be manufactured.

Starting from this one starting point forming point P (k0) of the robot is, if not already all points of the plane L are allocated (ie case N in the branch between IP and FCP in 2 ), for each robot by means of a method step FCP the inside of the plane L nearest next point P (k + 1) at which laser deposition welding is intended.

Is this next adjacent point P (k + 1) in the workspace of each robot and became this next adjacent point P (k + 1) not yet by the robot itself or each other's robot Rob1 . rob2 allocates and is this next adjacent point P (k + 1) not locked by the proximity to another of the robots (thus occurs case Y in the branch after FCP one), this point becomes P (k + 1) by the robot by means of the method step AP allocated (otherwise the case occurs N and a new new allowable next adjacent point is searched for, ie a new point for which the case Y entry).

Subsequently, the Euclidean distance of the newly allocated point becomes P (k + 1) to the previous allocated point P (k) by means of the method step CD calculated. Lies the Euclidean A was within a standard range (specified by a CAM software) (case N in the junction between CD and DSTOP), the next point is determined P (k + 2) and the procedure starts again.

If the distance exceeds the normal range between two processing points (case Y in the junction between CD and DSTOP ), so will the point P (k) by means of the method step DSTOP as a laser stop point and the point P (k + 1) by means of the method step DStart defined as a laser start point and as a starting point by means of the method step ASTART allocated.

Subsequently, the determination of the next point also takes place P (k + 2) and the continuation of the procedure. The process is terminated when all points of a level L are allocated (case Y in the junction between IP and FCP ).

The points can each be separately for each level L the respective robots Rob1 . rob2 can be assigned or it can be the levels L be processed in parallel.

In the method according to the invention is in the process step PALG the number of laser starting points and the laser endpoints is determined and as a measure of the quality of the assignment of the points at which laser-deposition welding is to be carried out to the respective robots Rob1 . rob2 used. This assignment is in the process step PALG optimized, in the illustrated embodiment such that the starting points P (k0) of the individual robot Rob1 . rob2 be varied, for example, such that the number of laser starting points is minimized.

Subsequently, in the method according to the invention, the assigned points become control commands for the individual robots Rob1 . rob2 translated and to the robots Rob1 . rob2 transfer, so the robots Rob1 . rob2 can actually carry out laser deposition welding.

In the process, all are robots Rob1 . rob23 connected to each other via a bus system (not shown in the drawing). By means of this bus system, each of the robots Rob1 . rob2 the operating status of the other robots Rob1 . rob2 Interrogate. Because to avoid collisions is only the simultaneous production of the workpiece WHO with all the robots Rob1 . rob2 one level L allowed. In case of error one of the robots Rob1 . rob2 is a pause of the rest of the robot Rob1 . rob2 required.

The robots Rob1 . rob2 together with the bus system form a production plant according to the invention.

In the 4 for example, points marked by crosses and circles P1 top left are the robot Rob1 assigned while the points P2 bottom right of the robot rob2 assigned. The points extend over a spatial dimension of horizontally and vertically each 300 millimeters.

Claims (11)

Method for the additive production of a component (WER) by means of laser deposition welding, in which the component is produced at the same time by means of at least two or more robots (ROB1, ROB2) respectively designed for laser deposition welding. Method according to Claim 1 in which the component (WER) is manufactured in successive layers (L), each layer (L) being produced at the same time by means of the at least two robots (ROB1, ROB2). Method according to one of the preceding claims, in which a set of laser deposition welding points (P (k), P (k + 1), P (k + 2)), in particular a laser deposition welding trajectory, for the production of the component is determined, each laser deposition weld point (P (k), P (k + 1), P (k + 2)) of this set is assigned to one, in particular only, one particular robot. Method according to one of the preceding claims, in which each of the robots (ROB1, ROB2) is assigned a working space within which the robot can laser-weld laser deposition welding points (P (k), P (k + 1), P (k + 2)). Method according to the preceding claim, in which each of the robots (ROB1, ROB2) has a spatial operating point (TCP1, TCP2), wherein each of the robots (ROB1, ROB2) is assigned an exclusivity environment around this operating point (TCP1, TCP2), none Robot (ROB1, ROB2) a Laserauftragsschweißpunkt (P (k), P (k + 1), P (k + 2)) within the exclusivity environment of another of the robot (ROB1, ROB2) is assigned. Method according to one of the preceding claims, in which each of the robots is assigned an initial laser deposition weld point. Method according to one of the preceding claims, in which each of the robots, starting from a respectively assigned laser deposition weld point, is assigned such a sufficiently small or as little as possible spaced subsequent laser deposition weld point, which is arranged within the working space of the robot and not already assigned to one of the robots and not within the exclusivity environment of one of the other robots is arranged. Method according to one of the preceding claims, wherein it is checked for each of the robots for an associated subsequent laser deposition weld, whether the Robot for laser deposition welding at the subsequent laser deposition weld has to start again. Method according to one of the preceding claims, in which the quantity of laser deposition welding points (P (k), P (k + 1), P (k + 2)) of at least one layer or of the entire component is assigned to robots such that a robot is as rare as possible for laser deposition welding at the subsequent laser deposition weld has to start again. Manufacturing device for additive production by means of laser deposition welding with at least two or more robots (ROB1, ROB2), which is designed to carry out the method, and in particular has a control unit which is designed for carrying out the method. Manufacturing device according to the preceding claim, in which the robots (ROB1, ROB2) and / or the control unit are signal-connected to one another.

Images