DE102018008873A1 - Method and apparatus for machining a workpiece with a jet - Google Patents

Abstract

Method for processing a workpiece with a beam, whereby a heat point (11) on the workpiece (3) and thus structure-borne sound waves (12) in the workpiece (3) are generated with the beam (4) and the structure-borne sound waves (12) are generated with a sensor (16) be detected.

Description

The invention relates to a method and an apparatus for processing a workpiece with a beam of high energy density, such as a beam processing machine, in particular for beam welding.

A variety of industrial beam processing machines, especially in welding processes especially those of the beam welding process use a variety of sensors for detecting the welding gap and the control of the beam to achieve the necessary quality and expression of the weld or machining a workpiece with a beam.

Machining a workpiece with a beam is understood to mean beam welding, such as, for example, laser beam welding, electron beam welding or plasma beam welding. Furthermore, in addition to the joining of workpiece parts, also jet cutting for cutting as processing, in particular electron beam cutting, laser beam cutting and plasma jet cutting or jet drilling, in particular electron beam drilling and laser drilling under machining a workpiece with a beam. The build-up welding, for example plasma jet spraying or the surface modification of a workpiece with a jet are also classified here. The processing can be carried out with the supply of an additional material, in particular welding filler material. For example, the filler materials may also be ceramic particles or hard materials dispersed in the surface and in near-surface layers. Also solders are to be understood as additional materials.

From the prior art, a variety of methods for guiding the beam during beam welding is known. Such is in the EP0770445B1 described. A disadvantage of this method is the need for two sensors to carry out. As a result, the process is more complicated. The method also does not disclose signal information indicative of the quality of the weld joint.

Further prior art is known, for example, from JPH04143084 (A). The apparatus and method teach the use of an ultrasonic probe to determine weld quality. A disadvantage of this device and method is the coupling of the ultrasonic probe for generating the ultrasound in the workpiece and simultaneous detection of the reflected signal.

Further prior art is for example off DE102010005896A1 known. The apparatus and method teach the use of a laser welding robot and a method for detecting the focal point by imaging techniques and the use of detectors to determine the position of the joint gap and the driving of the laser beam. However, the known method provides only information about the superficial design and position of the beam welding connection.

The object of the method and the device according to the invention is to overcome the disadvantages of the prior art, and to provide an economical method for machining a workpiece with a beam.

This object is achieved by a method according to the claims.

The method according to the invention is a method for processing a workpiece with a beam, wherein a heat point on the workpiece and thus structure-borne sound waves in the workpiece are generated with the beam and the structure-borne sound waves are detected with a sensor.

1. (i) positionieren eines Werkstücks zur Bearbeitung durch einen oder mehrere Strahlen, oder positionieren wenigstens zweier Werkstückteile zur Bearbeitung durch einen oder mehrere Strahlen zur Ausprägung einer Strahlbearbeitung, insbesondere Strahlschweiß- oder Lötverbindung
2. (ii) führen des Strahles und/oder des Werkstücks oder der Werkstückteile und Umlenken des Strahles zur Erzeugung einer lokalen Aufheizung an der Werkstückoberfläche zur Erzeugung von Körperschall im Werkstück
3. (iii) Messung der erzeugten Oberflächenbewegung des Körperschalls des Werkstücks mit einem Sensor

It is advantageous if the method according to the invention comprises the steps of

1. (I) position a workpiece for processing by one or more beams, or position at least two workpiece parts for processing by one or more beams for the expression of a beam processing, in particular beam welding or soldering connection
2. (ii) guiding the beam and / or the workpiece or the workpiece parts and deflecting the beam to produce a local heating on the workpiece surface to produce structure-borne noise in the workpiece
3. (iii) Measurement of the generated surface motion of the structure-borne noise of the workpiece with a sensor

The inventive method has the significant advantage that for the excitation of structure-borne noise, a high-energy beam is approximately massless, can be performed highly dynamically on any points of the workpiece, so not only generates frequencies that are orthogonal to the surface as in a pulse hammer or piezoelectric crystal be entered with the defined frequency. But one reaches one or more of the point propagating structure-borne sound waves and surface waves, such as longitudinally oscillating and transversely oscillating waves over a very wide frequency spectrum as a function of the duration of the heat pulse. Likewise, the method is executable so that one and the same point is cyclically excited. So can certain structure-borne sound wave patterns are achieved. Likewise, the excitation of structure-borne noise by the method according to the invention can be carried out in line form.

In all cases, the enormous advantage of non-contact stimulation of structure-borne noise is essential, thus an excitation occurs without coupling medium, which can also be used in vacuum such as electron beam welding equipment.

Another advantage is the wide freedom of the surface structure for excitation. In the case of piezocrystals, high demands are placed on the quality of the surface without coupling medium. By contrast, in the method according to the invention, it is possible to use both smooth but also rough, for example unprocessed, surfaces such as cast surfaces or saw-rough surfaces. Even structures such as ribs, engravings or similar raised as well as recessed form elements do not disturb the process.

The device according to the invention comprises a beam processing machine for processing a workpiece by a beam and / or welding at least two workpiece parts, a beam guiding mechanism for guiding the beam and / or at least one movement axis for moving the workpiece and / or the at least two workpiece parts and a sensor for detection the surface movement by structure-borne noise.

The expression according to the invention can also be a beam welding device for machining a workpiece by two or more jets or at least two workpiece parts. Such a beam-processing machine can have two or more beam-guiding mechanisms for guiding the beams and / or one or more movement axes for moving the workpiece and / or the at least two workpiece parts and one or more sensors for detecting the surface movement by structure-borne noise.

With the device mentioned above and the method mentioned above, it is possible in one embodiment to guide the jet highly dynamically and thus to machine a workpiece, while the execution of the processing by the jet generates a local heating of the surface by the jet. Due to the local temporal thermal expansion structure-borne noise is generated in the workpiece part. The structure-borne sound propagates through the workpiece and on the surface and is reflected back to interfaces, thereby producing surface movements, such as the back wall echo. The surface movements are detected by a sensor. The evaluation of the detected surface movement signal provides information about the geometry of the workpiece and / or quality of the machined workpiece. Likewise, this does not exist, or the weakening of an expected surface movement provides information about the extent of workpiece machining by the beam or the workpiece. In the simplest case, the sensor signal is monitored on a display, such as analog on an oscilloscope, or digitized on a display by operators.

With the above-mentioned device and the method mentioned above, it is also possible not only to process a workpiece but to form a welding and or solder joint through the beam to at least two workpiece parts. In this case, the welded connection can be executed over a certain geometric expression, for example over the entire thickness of the parts to be welded, and it is conceivable to produce the welded connection only over a defined welding depth, ie not over the entire cross section. The beam guidance generates local heating of the surface on one of the workpiece parts during the execution of the beam welding process. Due to the local thermal expansion, structure-borne noise is generated in the workpiece part. The structure-borne sound propagates through the workpiece part and on the surface and is thrown back to interfaces and thereby generates surface movements, for example a back wall echo. The surface movements are detected by a sensor. The evaluation of the detected surface movement signal provides information about the geometry of the workpiece parts and / or quality of the joined workpiece parts. Likewise, this does not exist, or the weakening of an expected surface movement provides information about the characteristics of the welded joint or machining of the workpiece by the beam. In the simplest case, the sensor signal is monitored on a display, such as analog on an oscilloscope, or digitized on a display by the operator.

In order to achieve a high-quality welding in the beam welding process, in particular electron-welding process, a highly accurate beam guidance on the weld joint of the workpieces to be joined is necessary. Geometrical deviations, such as the position of the weld joint, must be corrected in the beam guidance or in the workpiece positioning. For thickness tolerances of the workpieces, the parameters of the beam must be adapted to the extent of the weld to the deviations. For example, increasing the thickness of the workpieces to be joined will result in divergences such as incomplete penetration or insufficient seam exaggeration, and a large change in thickness may result in insufficient seam depth. Likewise leads one Reduced thickness, where appropriate, to sag the weld.

A further advantageous embodiment of the method is the storage of the sensor signal on a data memory. As a result, the signals can be assigned to the joined workpiece or the weld produced. Especially for quality assessment and batch tracking, these data are beneficial and can be used to improve quality and process. It is also conceivable evaluation of multiple data multiple welds to detect process capability fluctuations. Thus, it is possible to determine the tolerances of the workpiece parts as well as permissible material deviations such as alloying differences on their process capability. As a result, tolerances can be extended and previous processes such as the production and processing of the workpiece parts made more economical.

It is equally advantageous to supply the sensor signal to a programmable logic unit and to have it evaluated by a programmable logic unit. As a result, the signal is further billed and simplified for operators. An example simplification is the offsetting of the signal to information such as "okay" or "out of order". Other allocations can be, for example, the output of the calculated thickness information of a workpiece part. This results for example from the calculation of the duration of the structure-borne noise after the reflection at the boundary surface opposite the sensor.

A further advantageous embodiment is when the programmable logic controller is programmed so that the signal and / or other data such as process data of the beam source and the beam processing machine as input data for the calculation of the quality of the processing correlating valuation, in particular by a mathematical Model to allow an assessment of the quality. Such a mathematical model can also be a data pattern which is compared with validated data patterns.

A further advantageous embodiment is when the memory-programmable computer unit is programmed so that the calculated signal and / or other data such as process data of the beam source and the beam processing machine are used as input data for training an artificial neural network. The calculated input data are evaluated with the quality of the processing by a quality control. With the trained artificial neural network, the quality of the processing can then be assessed with a very high probability.

Likewise, it is advantageous to train the neural network with a simulation of the processing. In the process, a virtual model of the processing, for example a CAD model, is generated. The CAD model is transformed into a network of finite elements, such as hexahedra. The finite elements are assigned a material model of the material. With simulation software, the present, partially simplified model and the propagation of structure-borne noise can now be simulated. In a further step, the CAD model can be varied in its parameters. For example, the thickness of the workpiece can be changed in a defined gradation as in hundredths of a millimeter and the simulation model can be regenerated and evaluated. Thus, a free-scalable image of the reality can be generated and the influence of tolerances on the evaluation of the acquired sensor data can be determined with simulation. Since a freiskalierbares image of an already very simple processing with each additional scalable parameter in the number of solutions with their product grows and the simulation time of a finite element analysis (FEA) depending on the computing power can be time-consuming, it is advantageous to program a neural network , which is trained with the simulation results. A neural network is much easier and less time-consuming to evaluate in a software algorithm. Thus, while training the neural network, it takes a tremendous amount of time to perform the high number of simulations (FEA), but this can be accomplished through the programmed automatic generation of data such as the creation of the CAD model and the generation of the network of finite elements be automated. Ideally, a correspondingly powerful computer network can be used to train such a network. Whereas the trained neural network requires little computing power in its further application in software algorithms, for example the evaluation of the quality of the beam processing.

It is also advantageous if the trained neural network is further trained in the production process and further quality criteria. Thus, it is possible to enable adaptation, in particular machine learning, of the neural network via the current production.

Another characteristic provides to control the beam guidance by the programmable logic unit.

A further advantageous embodiment of the method is the regulation of the beam guidance a programmable logic unit by returning the sensor signal in the control loop of the beam guidance and / or beam generation. This will enable online process control.

A further advantageous embodiment of the method is the adjustment of the control of the beam guidance by a programmable logic unit by returning the sensor signal in the control loop of the beam guidance and / or beam generation. For example, can be done by measuring the thickness or the average thickness of the workpiece a balance of the expected maturities of the back wall echoes and so the process can be made more robust to tolerance variations in thickness. This will enable online blasting process control.

Particularly advantageous in generating the structure-borne noise by the beam as local heating is the broadband excitation of the workpiece part. Conventional sensors for generating structure-borne noise, such as piezocrystals, do not produce such broadband excitation. Due to the broadband excitation in a broad frequency spectrum, the sensor can detect the attenuation of certain frequencies in the signal and thus infer material properties such as the microstructure of the material. By way of example, it was possible with the method according to the invention to detect the structure change such as hardening of the material and the hardening depth during the machining with a jet. Such properties are otherwise detectable only destructive with Gefügeschliffen, microscopy and microhardness. Furthermore, the generation of structure-borne noise by a beam is an excitation in the workpiece part itself and it is possible even with a deflected beam, which is guided obliquely on the workpiece surface, possible to generate an excitation. Conventional sound generators preferably couple the signal across the surface in an orthogonal direction to the surface. For example, piezocrysts produce no or only small longitudinal waves in the surface. By contrast, a generated heat point also generates longitudinal waves in the surface due to the expansion. These longitudinal waves can preferably be used for transit time measurement on the surface and thus the position of interfaces to the excitation point can be determined. In particular, the distance of the heat point from a workpiece edge or joint connection can be determined. Thus, the method according to the invention can also detect the position of the joint gap and the beam guidance can be tuned to it.

In the expression of a beam welding connection, the microstructural change of the HAZ (heat-affected zone) across the weld joint from the unchanged base material of a workpiece part via a structural change as the coarse grain formation by the heat of the welding process to the structure by melting through the beam in the weld joint to structure change by the heat of the welding process second workpiece part to the unchanged base material of the second workpiece part. About the weld joint and the manifestation of the HAZ in the width across it can be assessed by the propagation delay and the attenuation by the structural change by the method according to the invention in the non-destructive quality.

Likewise, microstructural changes can be assessed non-destructively by welding a weld bead with or without welding filler to a workpiece by the method.

Likewise reflections and scattering of structure-borne noise at imperfections can be detected. Exemplary defects are pores and voids which form cavities. Also, binding errors are detectable which have no cavity, but have a phase boundary where no complete material bond is formed by melting the base material. This flaw may occur, for example, when the planar surfaces of the workpiece parts abut each other, but no fusion takes place by melting. For gluing, such an error is referred to as a kissing bond.

The method according to the invention can also be used if only a change in the surface or near-surface layer, such as a melting of only one workpiece part, in particular structural modification of the edge layer, is carried out by the beam. Such treatments are used, for example, for surface hardening or surface hardening. Also known by the cooling rate in the welding technology as t8 / 5 time depending on the alloy, the structure can be changed. Here, the lattice structure can change, for example with martensite, with the same chemical composition. Also, the grain size can be changed. Likewise, the distribution of different phases can change. Also, precipitates can lead to changes in the properties of the material.

The sound velocity of structure-borne noise also changes in different structures, since this is related to the elastic modulus. Chemically, the material has remained approximately the same in terms of composition. However, the structure of the structure described above is different. These transitions in the workpiece cause damping in the propagation of structure-borne noise. Thus, with the method according to the invention For example, a hardening layer thickness can be determined.

Likewise, the method according to the invention can be used for welding on a welding filler on at least one workpiece part. Welding additives are understood to mean solid wires, cored wires, strips and powders, which are supplied to the beam machining, in particular the welding process, or are applied to the workpiece part before or during beam machining. Likewise, when the material becomes molten, it can absorb or release elements when different materials are used. As a result, the damping is also changed and can be assessed non-destructively.

Assessment is the comparison of sensor signals with sensor signals from reference samples. With the reference samples, the sensor signal is determined by including all process parameters and then evaluated in terms of quality by means of exemplary microstructure, microscopy, hardness testing. For the process capability, sufficient reference samples are formed and a lower and upper tolerance limit are set. Thus, a determined sensor signal of a processing can be compared with the reference samples and, if it lies between the lower and upper tolerance, be judged as "OK". If the sensor signal is outside the tolerance range, it is judged to be "out of order". It is also advantageous to determine the reference samples by non-destructive testing such as computed tomography or X-ray.

The object for carrying out the method according to the invention is made possible by the device described below.

A beam welding system comprising a beam source, a beam guide for moving the beam relative to at least one workpiece table. A workpiece table for receiving at least one workpiece part. A sensor for detecting the surface movement of the at least one workpiece part. A display for displaying the sensor signal.

Furthermore, it is advantageous if the sensor is a vibrometer. Particularly advantageous is the use of a laser vibrometer. In a laser vibrometer, the surface movement is determined in a phase shift of the laser light by an interferometer. As a result, a particularly high-resolution detection of the surface movement is possible. Also advantageous is the non-contact detection of the surface movement by a laser vibrometer.

In a further embodiment of the invention, the sensor is connected to a memory-programmable computer unit. A data memory for storing the signal data can also be provided at this computer unit. Likewise, it is advantageous to run the data storage as a cloud and connect the computer unit through a communication link to a higher-level computer system. Preferred communication links are, for example, the widely used Profinet with a TCP / IP protocol. This enables high data transfer rates of up to 100 Mbit / s.

However, it is advantageous to carry out the control of the beam guidance and the billing of the control signal from the sensor data on separate memory-programmable computer units, wherein the control signal provided is provided cyclically in the control cycle of the programmable logic unit. Particularly advantageous is the execution of the rule and the beam guidance by a CNC memory programmable computer unit. Under CNC suitable synchronization for controlling several axes of motion in a certain, constant temporal cycle understood, whereby the movements generated are highly accurate.

A further advantageous embodiment of the device consists in the use of a movement axis for moving the workpiece table and the recorded workpiece at least relatively in a direction transverse to the beam. This makes it possible to process larger workpiece parts on the device.

Particularly advantageous is the control of the beam guidance in a defined area relative to the workpiece table and the regulation of the at least one movement axis of the workpiece table by the above-described programmable memory computer unit, wherein the movements can be superimposed to perform the method.

Likewise, it is conceivable that the at least one movement axis positions the at least one workpiece part on the workpiece table, the method is carried out by the beam guide and then the at least one movement axis moves the workpiece part to a further position and the method is executed. Here, the execution of the scheme is easier.

In an advantageous embodiment, the device has at least one movement axis for moving the sensor relative to the workpiece table.

When using a laser vibrometer, it is advantageous if the movement axis of the sensor moves the laser beam, for example by moving mirrors. As a result, a particularly dynamic movement of the point for detecting the surface movement of the workpiece part is possible.

When using a laser vibrometer, it is advantageous if the laser beam can be switched over an optical path to another point for detecting the surface movement of the workpiece part. By way of example, the beam can be switched over to another optical path by means of an activatable mirror. As a result, for example, the movements of the surface of the workpiece parts can be detected around the beam. For example, the beam can be detected in the direction of movement leading or lagging the surface movement. Likewise, the surface movement can be detected left and right of the beam in the direction of movement.

It is likewise expedient if the laser beam of the laser vibrometer is guided orthogonally onto the workpiece surface. Thus, mainly movements of the surface are detected in the orthogonal direction to the surface in the laser signal. Whereas structure-borne sound waves that propagate in the surface, such as longitudinal waves are hardly detected in the laser signal.

It is useful if the laser beam is at an oblique angle, i. is not orthogonally guided to the detection point. As a result, longitudinal waves and transverse waves of the surface can be detected.

It has proven particularly advantageous if the angle of the laser beam of the laser vibrometer with the surface can be changed. The more the angle is arranged out of the orthogonal direction to the surface, the larger the phase shift of the laser light of the laser vibrometer in the direction of the longitudinal wave in the surface.

It is advantageous if the device has a closed chamber in which the workpiece is processed. As a result, the chamber can be filled with a protective gas or a process gas, which is advantageous when using a laser beam. In this case, the chemical composition of the workpiece on the surface can change. For example, by using gases to harden the surface layer.

It is also possible to carry out the chamber as a vacuum chamber. Especially when using an electron beam.

Further advantageous embodiments and modifications of the invention will become apparent from the dependent claims and from the description in conjunction with the figures.

It should be noted at this point that the various variants of the method as well as the resulting advantages can be applied mutatis mutandis to the presented device and vice versa.

By way of introduction, it should be noted that the same parts are provided with the same reference numerals or the same component designations, wherein the disclosures contained in the entire description can be mutatis mutandis transferred to like parts with the same reference numerals or the same component designations. Also, the location information chosen in the description, such as top, bottom, side, etc. related to the immediately described and illustrated figure and are to be transferred to the new situation mutatis mutandis when a change in position. Furthermore, individual features or combinations of features from the exemplary embodiment shown and described can also represent independent, inventive or inventive solutions.

• 1 eine schematisch dargestellte Vorrichtung zur Bearbeitung zweier Werkstücketeile zur Ausprägung einer Schweißverbindung und Detektion der Oberflächenbewegung infolge der Ausbreitung eines durch einen Wärmepunkt erzeugten Körperschalls zur Regelung der Strahlführung;
• 2 eine schematisch dargestellte Vorrichtung zur Bearbeitung zweier Werkstücketeile zur Ausprägung einer Schweißverbindung und Detektion der Oberflächenbewegung infolge der Ausbreitung eines durch einen Wärmepunkt erzeugten Körperschalls zur Darstellung einer detektierten Fehlstelle;
• 3 eine schematisch dargestellte Vorrichtung zur Bearbeitung eines Werkstückteils zur Ausprägung einer Aufschweißung und Detektion der Oberflächenbewegung infolge der Ausbreitung und Dämpfung eines durch einen Wärmepunkt erzeugten Körperschalls zur Darstellung der Ermittlung der Ausprägung der Aufschweißung;
• 4 eine schematische Darstellung eines Werkstückteils und der Ausbreitung von Körperschall durch Wärmepunkte in der Draufsicht normal zum Strahl;

For a better understanding of the invention, this will be explained in more detail with reference to the following figures. Show it:

• 1 a schematically illustrated apparatus for processing two workpiece parts for the expression of a welded joint and detection of the surface movement due to the propagation of a structure-borne noise generated by a heat point for controlling the beam guidance;
• 2 a schematically illustrated device for processing two workpiece parts for the expression of a welded joint and detection of the surface movement due to the propagation of a structure-borne noise generated by a heat point to represent a detected defect;
• 3 a schematically illustrated apparatus for processing a workpiece part to the expression of a welding and detection of the surface movement due to the propagation and attenuation of a structure-borne noise generated by a heat point to illustrate the determination of the expression of the weld;
• 4 a schematic representation of a workpiece part and the propagation of structure-borne noise by thermal spots in plan view normal to the beam;

1 shows a schematically illustrated device ( 1 ) for machining two workpiece parts ( 2a . 2 B) to a workpiece ( 3 ) by means of a jet ( 4 ). The interface ( 5 ) forms by melting the workpiece parts ( 2a . 2 B ) the welded connection ( 6 ) out. The beam source ( 7 ) generates the beam and is guided by a beam guide ( 8th ) guided. The beam source ( 7 ) and the beam guide ( 8th ) are connected to a programmable logic unit ( 9 ) for controlling and controlling the jet ( 4 ) connected. So a deflected beam ( 4a) to any point on the surface ( 10 ) of the workpiece ( 3 ) or as shown here on workpiece part ( 2a) a heat point ( 11 ) produce. The generated structure-borne sound ( 12 ) runs through the workpiece part ( 2a) and will be on the opposite surface ( 13 ) reflected. The reflected structure-borne sound wave ( 14 ) generates a surface movement at the detection point ( 15 ). The sensor ( 16 ), for example, a laser vibrometer, detects the surface movement at the detection point ( 15 ) via a laser beam ( 17 ). The sensor signal ( 18 ) can be displayed via an ad ( 19 ) and or with the programmable logic unit ( 9 ) and or with a data memory ( 20 ). The programmable logic unit ( 9 ) can with a higher-level arithmetic unit, not shown, or a computer network via the communication link ( 21 ). The workpiece parts ( 2a . 2 B) are or the workpiece ( 3 ) is on a workpiece table ( 22 ) fixed. The workpiece table ( 22 ) can be moved via motion axes ( 24 ) relative to the base frame ( 23 ) are moved.

2 shows a schematically illustrated device ( 1 ) for machining two workpiece parts ( 2a . 2 B) to a workpiece ( 3 ) by means of a jet ( 4 ). The interface ( 5 ) forms by melting the workpiece parts ( 2a . 2 B) the welded connection ( 6 ) out. An error in the welded connection ( 6 ), for example, a binding error, breaks the weld joint and a part of the joint surface ( 5 ) remains unconnected. The beam source ( 7 ) generates the beam and is guided by a beam guide ( 8th ) to a deflected beam ( 4a) to any point on the surface ( 10 ) of the workpiece ( 3 ) or as shown here on workpiece part ( 2 B) guided and a heat point ( 11 ) generated. The generated structure-borne sound ( 12 ) runs through the workpiece part ( 2 B) and by the welded connection ( 6 ) and is on the opposite surface ( 13 ) reflected. The reflected structure-borne sound wave ( 14 ) generates a surface movement at the detection point ( 15 ). The sensor ( 16 ), for example, a laser vibrometer, detects the surface movement at the detection point ( 15 ) via a laser beam ( 17 ). The structure-borne sound wave ( 14a) in another reflection point of the surface ( 13 ) is at the interface ( 5 ) again and reaches the detection point ( 15a) not, shown in phantom here. As a result, the defect can be detected.

3 schematically shows a device ( 1 ) for machining a workpiece ( 3 ) for the expression of a weld-on ( 25 ). The beam ( 4 ) melts the surface ( 10 ) of the workpiece ( 3 ) on and by solidification of the molten bath ( 6a) arises the weld ( 25 ), which also by supplying a filler material or filler ( 26 ) other properties than the base material of the workpiece ( 3 ) may have. Likewise, by the cooling rate, a new material property of the workpiece in the weld ( 25 ) be generated. About the deflected beam ( 4a) gets on the surface ( 10a) the welding ( 25 ) a heat point ( 4 ) generates sound waves ( 14 ) and ( 14a ). A detection of the surface movement in the detection point ( 15 ) by a laser beam ( 17 ) allows, for example, the evaluation of the properties of the sound wave ( 14 ) and allows the determination of the expression of the connection of the weld ( 25 ). If the material properties are equal, the sound wave ( 14 ) less attenuated and less scattered or reflected. Microstructural changes of the weld ( 25 ) dissipate certain frequencies of broadband excitation. Likewise, a sound wave ( 14a) reflected at interfaces and can be detected in the detection point ( 15a) by a laser beam ( 17a) be detected. Interfaces also represent transitions in the material properties such as structural changes.

4 schematically shows the representation of a workpiece ( 3 ) consisting of the workpiece parts ( 2a) and ( 2 B ) on the workpiece table ( 22 ) normal to the beam ( 4 ). The welded connection ( 6 ) connects the workpiece parts ( 2 ) and ( 2 B ). At the time of welding, the area of the welded joint ( 6 ) a weld pool ( 6a) and molten. The welded connection ( 6 ) can be pronounced over the entire workpiece thickness (welded through) or else only have a certain thickness (welding depth). The deflected beam can cause heat spots ( 11 ) and ( 11a ) at any point on the workpiece part surface ( 10 ) produce. The structure-borne sound waves ( 12 ) and ( 12a ) spread in the excited workpiece part ( 2a) and depending on the presence of a welded joint ( 6 ) on the surface of the workpiece part ( 2 B) be detected. The interface ( 5 ) provides for the structure-borne sound wave ( 12a) represents an interface and reflects the structure-borne sound wave or attenuates the structure-borne sound wave ( 12a) so that the detection in the detection point ( 15a) only very weakly possible (dot-dashed arrow). A reflected structure-borne sound wave ( 12a) at the interface ( 5 ) generated in the detection point ( 15b) on the surface of the workpiece part ( 2a) a surface movement of the workpiece surface ( 10 ). By determining the Duration signal of the structure-borne sound wave ( 12a) in the detection point ( 15b) So can the location of the interface ( 5 ) are determined accurately. This makes it possible the beam guidance of the beam ( 4 ) to the location of the interface ( 5 ) and the quality and characteristics of the welded joint ( 6 ) are significantly improved. The properties of the welded joint ( 6 ), for example, via the detection of the structure-borne sound wave ( 12 ) be determined. For example, a plurality of heat points and detection points and sensor signals can be combined in any position. In addition, by time-dependent generation of heat points and detection points and detected sensor signals, a computational determination of the properties of the workpiece ( 3 ), in particular about the volume around the welded joint ( 6 ).

The embodiments show possible embodiments, it being noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but also various combinations of the individual embodiments are mutually possible and this variation possibility due to the teaching of technical action by representational invention in Can the expert working in this technical field.
The scope of protection is determined by the claims. However, the description and drawings are to be considered to interpret the claims. Individual features or combinations of features from the illustrated and described different embodiments may represent for themselves inventive solutions. The task underlying the independent inventive solutions can be taken from the description.
All information on ranges of values in objective description should be understood to include any and all sub-ranges thereof, eg the indication 1 to 10 to understand that all subsections, starting from the lower limit 1 and the upper limit 10 are encompassed, ie all subregions begin with a lower limit of 1 or greater and end at an upper limit of 10 or less, eg 1 to 1.7 or 3.2 to 8.1 or 5.5 to 10.
For the sake of order, it should finally be pointed out that, for better understanding of the structure, elements have been shown partially unmeshold and / or enlarged and / or reduced in size.

LIST OF REFERENCE NUMBERS

1

device

2a, 2b

Workpieces Parts

3

workpiece

4

beam

4a

deflected beam

5

interface

6

welded joint

7

beam source

8th

beamline

9

computer unit

10

surface

11

heat spot

12

structure-borne sound

13

opposite surface

14a-b

BAW

15a-b

detection point

16

sensor

17,17a

laser beam

18

sensor signal

19

display

20

data storage

21

communication link

22

Worktable

23

base frame

24

motion axes

25

hardfacing

26

Additional material / welding filler

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• EP 0770445 B1 [0004]
• DE 102010005896 A1 [0006]

Claims (15)

A method for processing a workpiece with a beam characterized in that the beam (4) a heat point (11) on the workpiece (3) and so structure-borne sound waves (12) in the workpiece (3) are generated and with a sensor (16) the structure-borne sound waves ( 12) are detected. Method according to Claim 1 characterized in that the beam is dynamically deflected during processing and the deflected beam (4a) generates the heat point (11) on the workpiece (3) and thus the structure-borne sound waves (12). Method according to Claim 1 characterized in that the sensor signal (18) of the sensor (16) is displayed on a display (19). Method according to Claim 1 characterized in that the sensor signal (18) is recorded on a data memory (20). Method according to Claim 1 characterized in that the sensor signal (18) is evaluated in a computer unit (9) for a quality assessment of the workpiece (3) processed by the beam (4). Method according to Claim 1 characterized in that the sensor signal (18) in a computer unit (9) via a communication link (21) is transferred to a higher-level computer system or data storage. Method according to Claim 1 characterized in that the sensor signal (18) in the computing unit (9) for the control of the beam guide (8) and / or the axes of movement (24) of the workpiece (3) is used. Method according to Claim 5 characterized in that an algorithm using a neural network is used on the arithmetic unit (9). Apparatus for processing a workpiece by a jet characterized in that a sensor (16) for measuring the surface movement of the workpiece (3) is arranged. Device after Claim 9 characterized in that the sensor (16) is a laser vibrometer. Device after Claim 10 characterized in that the laser vibrometer is directed obliquely on the surface of the workpiece (3). Device after Claim 9 characterized in that the sensor (16) relative to the surface of the workpiece (3) is displaceable. Device after Claim 9 characterized in that the beam (4) for processing the workpiece (3) is an electron beam. Device after Claim 9 characterized in that the beam (4) relative to the workpiece (3) is displaceable. Device after Claim 9 characterized in that the beam (4) relative to the workpiece (3) is displaceable and that a machining of the workpiece (3) by the beam (4) and a generation of a heat point (11) on the surface (10) of the workpiece (3) by a deflected beam (4a).

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