WO1989001385A1 - Workpiece-machining device - Google Patents

Workpiece-machining device Download PDF

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Publication number
WO1989001385A1
WO1989001385A1 PCT/DE1988/000424 DE8800424W WO8901385A1 WO 1989001385 A1 WO1989001385 A1 WO 1989001385A1 DE 8800424 W DE8800424 W DE 8800424W WO 8901385 A1 WO8901385 A1 WO 8901385A1
Authority
WO
WIPO (PCT)
Prior art keywords
workpiece
radiation
laser
wavelength
heat
Prior art date
Application number
PCT/DE1988/000424
Other languages
German (de)
French (fr)
Inventor
Friedrich Dausinger
Werner Müller
Eckart Von Roda
Original Assignee
Robert Bosch Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Publication of WO1989001385A1 publication Critical patent/WO1989001385A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/03—Observing, e.g. monitoring, the workpiece
    • B23K26/032—Observing, e.g. monitoring, the workpiece using optical means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/03—Observing, e.g. monitoring, the workpiece
    • B23K26/034—Observing the temperature of the workpiece
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/06—Surface hardening
    • C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation

Definitions

  • the invention relates to a workpiece processing device according to the preamble of the main claim.
  • a device for machining workpieces by means of laser beams has become known which allows an accurate, direct temperature measurement of a heated area of the workpiece to be machined.
  • the device is equipped with a radiation detector which is exposed to the heat radiation of the workpiece heated by the laser beam.
  • the radiation detector emits an output signal which is dependent on the strength of the thermal radiation and which is evaluated for the power control of the laser.
  • the zone of the workpiece to be processed, for example to be hardened, is heated by the laser beam, which essentially has a single, relatively large wavelength.
  • the intensity of the heat radiation emitted as a result of the local heating of the workpiece is measured and the power of the laser beam is controlled as a function of the intensity of the measured heat radiation.
  • the heating of the workpiece zone is ended as soon as the measured intensity reaches a predetermined threshold value.
  • the laser is either switched off or the laser beam is interrupted by means of a cover which can be introduced into the beam path. Good results can be achieved with this because the Workpiece surface is no longer heated and not at a higher temperature than is required for the respective processing.
  • the radiation detector is arranged in such a way that it is hit directly by the heat radiation emanating from the workpiece.
  • the workpiece machining device according to the invention with the characterizing features of the main claim has the advantage that it is suitable for temperature-controlled or temperature-controlled machining of both external and internal workpiece surfaces by means of laser radiation with constant accuracy of the temperature measurement.
  • Each heat treatment process on a workpiece can be carried out in a temperature-controlled or temperature-controlled manner.
  • a particularly advantageous embodiment of the device consists in that a heat reflection filter is used as the reflector, which filter is essentially transparent to the radiation with the wavelength of the laser radiation and is essentially impermeable to the heat radiation emanating from the workpiece.
  • FIG. 1 An embodiment of the invention is shown in the drawing and explained in more detail in the following description.
  • the figure shows an overall schematic view of the workpiece machining device.
  • 1 designates a laser which is known per se and which emits a beam 2 which is essentially of a single wavelength.
  • a workpiece 3 to be machined with an inner bore 4 is arranged on an adjustable support (not shown) in such a way that the bottom 5 of the bore 4 is heated by the laser beam 2, for example for the purpose of surface hardening.
  • a mirror 6 is arranged, which deflects the radiation in the direction of the workpiece 3.
  • a focusing device 7, for example in the form of a lens, lies between the mirror 6 and the workpiece 3 in the beam path of the laser beam 2 in order to focus it on the bottom 5 of the bore 4 or at another desired location on the workpiece.
  • the heat radiation emanating from the workpiece 3 when it is heated (IR radiation of the wavelength 780 nm-1 mm) is recorded by a radiation detector 9 which responds to the wavelength range of this radiation.
  • a reflector 10 designed as a plane plate is arranged in the beam path 2 of the laser 1, which is transparent to the laser radiation 2 while deflecting the heat radiation 8 emitted by the workpiece 3 in the direction of the detector 9.
  • the latter supplies an electrical output signal which is proportional to the strength of the heat radiation 8 and which, after amplification, is fed as an actual value to a control circuit 11 to which the laser 1 is connected.
  • the control circuit 11 endeavors to keep the laser power, ie the energy of the beam 2, at a setpoint previously entered in the control circuit.
  • a carbon dioxide (CO) laser whose radiation has a wavelength of approximately 10.6 ⁇ m is preferably used as the laser.
  • Pyroelectric detectors can be used as radiation detectors, which have their greatest sensitivities at wavelengths of approximately 800 nm - 5 ⁇ m.
  • the wavelength and the intensity of the heat radiation of the workpiece 3 depend on its temperature. When the temperature rises, the intensity of the heat radiation increases and its peak wavelength shifts in the direction of smaller wavelengths. However, the values always differ significantly from the wavelength of the laser radiation, which in the case of a CO laser is considerably longer-wave than the thermal radiation of the workpiece 3. It is thus possible to determine the temperatures in the area in which the workpiece is heated to measure directly. The workpiece can thus always be brought to the same temperature, regardless of the output power of the laser.
  • That part of the heat radiation of the heated workpiece 3 which is coaxial or parallel to the laser beam 2 is detected and evaluated in the proposed workpiece processing device.
  • This part of the heat radiation is reflected out of the beam path at one point - in the exemplary embodiment between deflecting mirror 6 and laser 1 - and fed to the radiation detector 9. Since the wavelengths of the heat radiation and the laser radiation differ significantly from one another, a clean separation by means of a heat reflection filter 12 is possible, which is impermeable to the heat radiation 8 but essentially transparent to the laser radiation 2.
  • the heat reflection filter 12 is applied in the form of, for example, a vapor-deposited coating on a carrier which is transparent to the laser radiation 2, for example a glass plate 13.
  • the heat reflection filter 11 is preferably designed as a multilayer interference filter with a blocking area for the heat radiation 8 emanating from the workpiece 3 and a pass-through area for the laser radiation 2.
  • the workpiece machining device described is preferably used for surface hardening of workpieces, with the advantage that internal zones, for example bores and the like, can also be hardened in a heat-controlled manner.
  • the device can also be used for cutting and welding materials, the radiation detector 9 ensuring that the power of the laser 1 is in each case based on a predetermined setpoint. Both the surface treatment and the joining and separating are possible with a minimum of heat introduced, the beam guidance allowing a heat-controlled treatment in difficult to access places.
  • the laser selected is a CO laser with an initial wavelength of approximately 10.6 ⁇ m
  • lasers which work at a different wavelength can also be used.
  • a YAG laser could be used, the radiation of which has a wavelength of approximately 1.06 ⁇ m. It is essential that the wavelength of the laser radiation differs from the wavelength of the IR radiation emitted by the heated workpiece.
  • the parallel beam guidance of the cavity radiation to the laser radiation enables precise heat treatment at every point on the workpiece that can be reached by the laser beam.

Abstract

The invention concerns a workpiece-machining device with a laser (1) and a radiation detector (9) exposed to the thermal radiation (8) from the heated workpiece (3) for regulating the output of the laser (1). A reflector (10) permeable to the laser radiation (2) is arranged in the path of the laser beam and directs the thermal radiation (8) from the workpiece (3) to the detector (9) located outside the path of the laser beam.

Description

WerkstückbearbeitunσsVorrichtung Workpiece processing device
Stand der TechnikState of the art
Die Erfindung geht aus von einer Werkstück-Bearbeitungsvorrichtung nach der Gattung des Hauptanspruchs. Durch die DE-OS 22 00 696 ist eine Einrichtung zur Bearbeitung von Werkstücken mittels Laserstrah¬ len bekannt geworden, welche eine genaue, direkte Temperaturmessung eines erhitzten Bereiches des zu bearbeitenden Werkstückes erlaubt. Hierzu ist die Einrichtung mit einem Strahlungsdetektor ausgerüstet, welcher der Wärmestrahlung des vom Laserstrahl erhitzten Werkstücks ausgesetzt ist. Der Strahlungsdetektor gibt ein von der Stärke der Wärmestrahlung abhängiges Ausgangssignal ab, das zur LeistungsSteue¬ rung des Lasers ausgewertet wird. Die zu bearbeitende, beispielswei¬ se zu härtende Zone des Werkstücks wird durch den Laserstrahl aufge¬ heizt, der im wesentlichen eine einzige, relativ große Wellenlänge aufweist. Die Intensität der infolge der örtlichen Erhitzung des Werkstücks abgegebenen Wärmestrahlung wird gemessen und die Leistung des Laserstrahls in Abhängigkeit von der Intensität der gemessenen Wärmestrahlung gesteuert. Die Aufheizung der Werkstückzone wird be¬ endet, sobald die gemessene Intensität einen vorgegebenen Schwell¬ wert erreicht. Hierzu wird der Laser entweder abgeschaltet oder der Laserstrahl mittels einer in den Strahlengang einbringbaren Abdek- kung unterbrochen. Damit lassen sich gute Resultate erzielen, da die Werkstückoberfläche nicht länger und nicht mit höherer Temperatur erhitzt wird als es für die jeweilige Bearbeitung erforderlich ist. Der Strahlungsdetektor ist bei der bekannten Vorrichtung so angeord¬ net, daß er von der vom Werkstück ausgehenden Wärmestrahlung direkt getroffen wird. Dies bedeutet, daß die Steuerung des Lasers nur dann zufriedenstellend funktioniert, wenn außenliegende Zonen eines Werk¬ stücks bearbeitet werden, die der Strahlungsdetektor "sehen" kann. Für die Bearbeitung innenllegender Flächen von Werkstücken, wie Boh¬ rungen, Innengewinde und dergleichen ist die bekannte Einrichtung hingegen nicht oder weniger gut geeignet, da die Wärmestrahlung zum Detektor hin durch das Werkstück abgeschirmt ist.The invention relates to a workpiece processing device according to the preamble of the main claim. From DE-OS 22 00 696, a device for machining workpieces by means of laser beams has become known which allows an accurate, direct temperature measurement of a heated area of the workpiece to be machined. For this purpose, the device is equipped with a radiation detector which is exposed to the heat radiation of the workpiece heated by the laser beam. The radiation detector emits an output signal which is dependent on the strength of the thermal radiation and which is evaluated for the power control of the laser. The zone of the workpiece to be processed, for example to be hardened, is heated by the laser beam, which essentially has a single, relatively large wavelength. The intensity of the heat radiation emitted as a result of the local heating of the workpiece is measured and the power of the laser beam is controlled as a function of the intensity of the measured heat radiation. The heating of the workpiece zone is ended as soon as the measured intensity reaches a predetermined threshold value. For this purpose, the laser is either switched off or the laser beam is interrupted by means of a cover which can be introduced into the beam path. Good results can be achieved with this because the Workpiece surface is no longer heated and not at a higher temperature than is required for the respective processing. In the known device, the radiation detector is arranged in such a way that it is hit directly by the heat radiation emanating from the workpiece. This means that the control of the laser only works satisfactorily if external zones of a workpiece are machined, which the radiation detector can "see". In contrast, the known device is not or less well suited for the processing of internal surfaces of workpieces, such as bores, internal threads and the like, since the heat radiation to the detector is shielded by the workpiece.
Vorteile der ErfindungAdvantages of the invention
Die erfindungsgemäße Werkstückbearbeitungsvorrichtung mit den kenn¬ zeichnenden Merkmalen des Hauptanspruchs hat demgegenüber den Vor¬ teil, daß sie zum temperaturgesteuerten bzw. temperaturgeregelten Bearbeiten sowohl außen- als auch innenliegender Werkstückflächen mittels LaserStrahlung bei gleichbleibender Genauigkeit der Tempe¬ raturmessung geeignet ist. Jeder Wärmebehandlungsprozeß an einem Werkstück kann so temperaturgesteuert bzw. temperaturgeregelt aus¬ geführt werden.In contrast, the workpiece machining device according to the invention with the characterizing features of the main claim has the advantage that it is suitable for temperature-controlled or temperature-controlled machining of both external and internal workpiece surfaces by means of laser radiation with constant accuracy of the temperature measurement. Each heat treatment process on a workpiece can be carried out in a temperature-controlled or temperature-controlled manner.
Durch die in den Unteransprüchen aufgeführten Maßnahmen sind vor¬ teilhafte Weiterbildungen und Verbesserungen der im Hauptanspruch vorgeschlagenen Werkstück-Bearbeitungsvorrichtung möglich. Eine besonders vorteilhafte Ausgestaltung der Vorrichtung besteht darin, daß als Reflektor ein Wärmereflexionsfilter dient, welches im we¬ sentlichen durchlässig ist für die Strahlung mit der Wellenlänge der Laserstrahlung und im wesentlichen undurchlässig ist für die vom Werkstück ausgehende Wärmestrahlung. ZeichnungThe measures listed in the subclaims enable advantageous further developments and improvements of the workpiece machining device proposed in the main claim. A particularly advantageous embodiment of the device consists in that a heat reflection filter is used as the reflector, which filter is essentially transparent to the radiation with the wavelength of the laser radiation and is essentially impermeable to the heat radiation emanating from the workpiece. drawing
Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung darge¬ stellt und in der nachfolgenden Beschreibung näher erläutert. Die Figur zeigt eine schematische Gesamtansicht der Werkstück-Bearbei¬ tungsvorrichtung.An embodiment of the invention is shown in the drawing and explained in more detail in the following description. The figure shows an overall schematic view of the workpiece machining device.
Beschreibung des AusführungsbeispielsDescription of the embodiment
In der Figur ist mit 1 ein Laser an sich bekannter Bauart bezeich¬ net, der ein im wesentlichen eine einzige Wellenlänge aufweisendes Strahlenbündel 2 aussendet. Ein zu bearbeitendes Werkstück 3 mit ei¬ ner Innenbohrung 4 ist auf einem nicht gezeigten, verstellbaren Trä¬ ger so angeordnet, daß der Boden 5 der Bohrung 4 durch den Laser¬ strahl 2, beispielsweise zwecks Oberflächenhärtung erhitzt wird. Im Wege des Strahlenbündels 2 ist ein Spiegel 6 angeordnet, welcher die Strahlung in Richtung des Werkstücks 3 umlenkt. Eine beispielsweise als Linse ausgebildete Fokussiereinrichtung 7 liegt zwischen Spiegel 6 und Werkstück 3 im Strahlengang des Laser-Strahlenbündels 2, um dieses am Boden 5 der Bohrung 4 oder an einer anderen gewünschten Stelle des Werkstücks zu fokussieren. Die vom Werkstück 3 bei dessen Erhitzung ausgehende Wärmestrahlung (IR-Strahlung der Wellenlänge 780 nm - 1 mm) wird von einem auf den Wellenlängenbereich dieser Strahlung ansprechenden Strahlungsdetektor 9 aufgenommen. Zu diesem Zweck ist im Strahlengang 2 des Lasers 1 ein als Planplatte ausge¬ bildeter Reflektor 10 angeordnet, welcher für die Laserstrahlung 2 durchlässig ist, während er die vom Werkstück 3 abgegebene Wärme¬ strahlung 8 in Richtung des Detektors 9 ablenkt. Letzter liefert ein der Stärke der Wärmestrahlung 8 proportionales elektrisches Aus¬ gangssignal, das nach Verstärkung als Istwert einem Regelkreis 11 zugeführt wird, an den der Laser 1 angeschlossen ist. Der Regelkreis 11 ist bestrebt, die Laserleistung, d.h. die Energie des Strahlen¬ bündels 2 auf einem zuvor in den Regelkreis eingegebenen Sollwert zu halten. Als Laser wird vorzugsweise ein Kohlendioxyd-(C0 )-Laser verwen¬ det, dessen Strahlung eine Wellenlänge von etwa 10,6 um aufweist. Als Strahlungsdetektoren können pyroelektrische Detektoren benutzt werden, die bei Wellenlängen von etwa 800 nm - 5 um ihre größte Empfindlichkeiten aufweisen. Die Wellenlänge und die Intensität der Wärmestrahlung des Werkstücks 3 sind von dessen Temperatur abhängig. Bei einem Temperaturanstieg nimmt die Intensität der Wärmestrahlung zu und ihre Spitzenwellenlänge verschiebt sich in Richtung kleinerer Wellenlängen. Die Werte unterscheiden sich aber immer deutlich von der Wellenlänge der Laserstrahlung, die bei einem CO -Laser erheb¬ lich langwelliger ist als die Wärmestrahlung des Werkstücks 3. Es ist somit möglich, die Temperaturen in dem Bereich, in dem das Werk¬ stück aufgeheizt wird, direkt zu messen. Das Werkstück kann damit immer auf gleiche Temperatur gebracht werden, unabhängig von der Ausgangsleistung des Lasers.In the figure, 1 designates a laser which is known per se and which emits a beam 2 which is essentially of a single wavelength. A workpiece 3 to be machined with an inner bore 4 is arranged on an adjustable support (not shown) in such a way that the bottom 5 of the bore 4 is heated by the laser beam 2, for example for the purpose of surface hardening. In the path of the beam 2, a mirror 6 is arranged, which deflects the radiation in the direction of the workpiece 3. A focusing device 7, for example in the form of a lens, lies between the mirror 6 and the workpiece 3 in the beam path of the laser beam 2 in order to focus it on the bottom 5 of the bore 4 or at another desired location on the workpiece. The heat radiation emanating from the workpiece 3 when it is heated (IR radiation of the wavelength 780 nm-1 mm) is recorded by a radiation detector 9 which responds to the wavelength range of this radiation. For this purpose, a reflector 10 designed as a plane plate is arranged in the beam path 2 of the laser 1, which is transparent to the laser radiation 2 while deflecting the heat radiation 8 emitted by the workpiece 3 in the direction of the detector 9. The latter supplies an electrical output signal which is proportional to the strength of the heat radiation 8 and which, after amplification, is fed as an actual value to a control circuit 11 to which the laser 1 is connected. The control circuit 11 endeavors to keep the laser power, ie the energy of the beam 2, at a setpoint previously entered in the control circuit. A carbon dioxide (CO) laser whose radiation has a wavelength of approximately 10.6 μm is preferably used as the laser. Pyroelectric detectors can be used as radiation detectors, which have their greatest sensitivities at wavelengths of approximately 800 nm - 5 μm. The wavelength and the intensity of the heat radiation of the workpiece 3 depend on its temperature. When the temperature rises, the intensity of the heat radiation increases and its peak wavelength shifts in the direction of smaller wavelengths. However, the values always differ significantly from the wavelength of the laser radiation, which in the case of a CO laser is considerably longer-wave than the thermal radiation of the workpiece 3. It is thus possible to determine the temperatures in the area in which the workpiece is heated to measure directly. The workpiece can thus always be brought to the same temperature, regardless of the output power of the laser.
Wie bereits erwähnt, wird bei der vorgeschlagenen Werkstück-Bearbei¬ tungsvorrichtung derjenige Teil der Wärmestrahlung des erhitzten Werkstücks 3 erfaßt und ausgewertet, welcher koaxial bzw. parallel zum Laserstrahl 2 verläuft. Dieser Teil der Wärmestrahlung wird an einer Stelle - im Ausführungsbeispiel zwischen Umlenkεpiegel 6 und Laser 1 - aus dem Strahlengang ausgespiegelt und dem Strahlendetek¬ tor 9 zugeführt. Da die Wellenlängen der Wärmestrahlung und der Laserstrahlung deutlich voneinander abweichen, ist eine saubere Trennung mittels eines Wärmereflexionsfilters 12 möglich, welches für die Wärmestrahlung 8 undurchlässig, für die Laserstrahlung 2 hingegen im wesentlichen durchlässig ist. Das Wärmereflexionsfilter 12 ist in Form eines beispielsweise aufgedampften Belags auf einem für die Laserstrahlung 2 durchlässigen Träger, beispielsweise einer Glasplatte 13, aufgebracht. Vorzugsweise ist das Wärmereflexionsfil¬ ter 11 als Mehrschichten-Interferenz-Filter mit einem Sperrbereich für die vom Werkstück 3 ausgehende Wärmestrahlung 8 und einem Durch¬ laßbereich für die Laserstrahlung 2 ausgebildet. Die beschriebene Werkstück-Bearbeitungsvorrichtung wird vorzugsweise zum Oberflächenhärten von Werkstücken verwendet, mit dem Vorteil, daß auch innenliegende Zonen, beispielsweise Bohrungen und der¬ gleichen, wärmegeregelt gehärtet werden können. Darüber hinaus ist die Vorrichtung aber auch zum Schneiden und Schweißen von Werkstof¬ fen einsetzbar, wobei der Strahlungsdetektor 9 dafür sorgt, daß sich die Leistung des Lasers 1 jeweils an einem vorgegebenen Sollwert orientiert. Sowohl die Oberflächenbehandlung als auch das Fügen und Trennen sind mit einem Minimum an eingebrachter Wärme möglich, wobei die Strahlführung eine wärmegeregelte Behandlung an schwierig zu¬ gänglichen Stellen erlaubt.As already mentioned, that part of the heat radiation of the heated workpiece 3 which is coaxial or parallel to the laser beam 2 is detected and evaluated in the proposed workpiece processing device. This part of the heat radiation is reflected out of the beam path at one point - in the exemplary embodiment between deflecting mirror 6 and laser 1 - and fed to the radiation detector 9. Since the wavelengths of the heat radiation and the laser radiation differ significantly from one another, a clean separation by means of a heat reflection filter 12 is possible, which is impermeable to the heat radiation 8 but essentially transparent to the laser radiation 2. The heat reflection filter 12 is applied in the form of, for example, a vapor-deposited coating on a carrier which is transparent to the laser radiation 2, for example a glass plate 13. The heat reflection filter 11 is preferably designed as a multilayer interference filter with a blocking area for the heat radiation 8 emanating from the workpiece 3 and a pass-through area for the laser radiation 2. The workpiece machining device described is preferably used for surface hardening of workpieces, with the advantage that internal zones, for example bores and the like, can also be hardened in a heat-controlled manner. In addition, however, the device can also be used for cutting and welding materials, the radiation detector 9 ensuring that the power of the laser 1 is in each case based on a predetermined setpoint. Both the surface treatment and the joining and separating are possible with a minimum of heat introduced, the beam guidance allowing a heat-controlled treatment in difficult to access places.
Obwohl bei der bevorzugten Ausführungsform der gewählte Laser ein CO -Laser mit einer Ausgangsweilenlänge von etwa 10,6 um ist, können auch Laser verwendet werden, die mit einer anderen Wellenlän¬ ge arbeiten. So könnte beispielsweise ein YAG-Laser verwendet wer¬ den, dessen Strahlung eine Wellenlänge von etwa 1,06 um aufweist. Wesentlich ist, daß sich die Wellenlänge der Laserstrahlung von der Wellenlänge der vom erhitzten Werkstück abgegebenen IR-Strahlung un¬ terscheidet. Die parallele Strahlführung der Hohlraumstrahlung zur Laserstrahlung macht eine präzise Wärmebehandlung an jeder, vom Laserstrahl zu erreichenden Stelle des Werkstücks möglich. Although in the preferred embodiment the laser selected is a CO laser with an initial wavelength of approximately 10.6 μm, lasers which work at a different wavelength can also be used. For example, a YAG laser could be used, the radiation of which has a wavelength of approximately 1.06 μm. It is essential that the wavelength of the laser radiation differs from the wavelength of the IR radiation emitted by the heated workpiece. The parallel beam guidance of the cavity radiation to the laser radiation enables precise heat treatment at every point on the workpiece that can be reached by the laser beam.

Claims

Ansprüche Expectations
1. Werkstückbearbeitungsvorrichtung, insbesondere zum Oberflächen¬ härten von Werkstücken, mit einem Laser, der eine im wesentlicher: eine einzige Wellenlänge aufweisende Strahlung erzeugt sowie mit ei¬ ner Fokussiervorrichtung zum Bündeln des Laserstrahls auf dem Werk¬ stück und einem Strahlungsdetektor, welcher der Wärmestrahlung des erhitzten Werkstücks ausgesetzt ist und ein von der Stärke dieser Strahlung abhängiges Ausgangssignal liefert, das zur Leistungεsteue- rung des Lasers ausgewertet wird, dadurch gekennzeichnet, daß im Strahlengang des Lasers (1) ein für die Strahlung mit der Wellenlän¬ ge des Laserstrahls (2) durchlässiger Reflektor (10) angeordnet ist, welcher vom Werkstück (3) abgegebene Wärmestrahlung (8) zu dem au¬ ßerhalb des Strahlengangs angeordneten Strahlungsdetektor (9) lenkt.1. Workpiece processing device, in particular for surface hardening of workpieces, with a laser which essentially produces radiation having a single wavelength and with a focusing device for focusing the laser beam on the workpiece and a radiation detector which detects the heat radiation of the is exposed to a heated workpiece and provides an output signal which is dependent on the strength of this radiation and which is evaluated for the power control of the laser, characterized in that in the beam path of the laser (1) one for the radiation with the wavelength of the laser beam (2) Permeable reflector (10) is arranged, which directs heat radiation (8) emitted by the workpiece (3) to the radiation detector (9) arranged outside the beam path.
2. Werkstückbearbeitungsvorrichtung nach Anspruch 1, dadurch gekenn¬ zeichnet, daß als Reflektor (10) ein Wärmereflexionsfilter (12) dient, welches im wesentlichen durchlässig ist für die Strahlung mit der Wellenlänge des Laserstrahls (2) und im wesentlichen undurchläs¬ sig ist für die vom Werkstück (3) ausgehende Wärmestrahlung (8).2. Workpiece processing apparatus according to claim 1, characterized gekenn¬ characterized in that a heat reflection filter (12) is used as the reflector (10) which is substantially transparent to the radiation with the wavelength of the laser beam (2) and is substantially impermeable to the heat radiation (8) emanating from the workpiece (3).
3. Werkstückbearbeitungsvorrichtung nach Anspruch 2, dadurch gekenn¬ zeichnet, daß das Wärmereflexionsfilter (12) als Mehrschichten-In¬ terferenzfilter mit einem Sperrbereich für die vom Werkstück (3) ausgehende Wärmestrahlung (8) und einem Durchlaßbereich für die Laserstrahlung (2) ausgebildet ist. 3. Workpiece machining device according to claim 2, characterized gekenn¬ characterized in that the heat reflection filter (12) is designed as a multilayer interference filter with a blocking area for the heat radiation (8) emanating from the workpiece (3) and a passband for the laser radiation (2) .
4. Werkstückbearbeitungsvorrichtung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß der Laser (1) ein Kohlen- dioxydlaser ist, der einen Laserstrahl mit einer Wellenlänge von etwa 10,6 um abgibt. 4. Workpiece processing device according to one of the preceding claims, characterized in that the laser (1) is a carbon dioxide laser which emits a laser beam with a wavelength of about 10.6 µm.
PCT/DE1988/000424 1987-08-08 1988-07-07 Workpiece-machining device WO1989001385A1 (en)

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DE19873726466 DE3726466A1 (en) 1987-08-08 1987-08-08 WORKPIECE MACHINING DEVICE

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WO1994006943A1 (en) * 1992-09-24 1994-03-31 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e. V. Process for changing the microstructure of metallic rails
WO2015197249A1 (en) * 2014-06-27 2015-12-30 Robert Bosch Gmbh Method for producing a component element
US10583668B2 (en) 2018-08-07 2020-03-10 Markem-Imaje Corporation Symbol grouping and striping for wide field matrix laser marking

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DE4025851A1 (en) * 1990-08-16 1992-02-20 Messerschmitt Boelkow Blohm DEVICE FOR MEASURING REFLECTED RADIATION
DE4028974A1 (en) * 1990-09-12 1992-03-19 Siemens Ag Determining the optimal focal point of laser beam - by measuring time for max. light intensity for each focal distance and lowest pt. on resultant graph plotting distance against time
DE4310409C2 (en) * 1993-03-31 1998-01-15 Dresden Ev Inst Festkoerper Method and device for beam diagnosis in the defined laser irradiation
DE9403822U1 (en) * 1994-03-08 1995-07-06 Thyssen Laser Technik Gmbh Monitoring device for laser radiation
DE10259177B4 (en) * 2002-12-18 2010-11-04 Robert Bosch Gmbh Method for carrying out a welding process

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WO1994006943A1 (en) * 1992-09-24 1994-03-31 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e. V. Process for changing the microstructure of metallic rails
WO2015197249A1 (en) * 2014-06-27 2015-12-30 Robert Bosch Gmbh Method for producing a component element
CN106471137A (en) * 2014-06-27 2017-03-01 罗伯特·博世有限公司 Method for manufacturing element
US10583668B2 (en) 2018-08-07 2020-03-10 Markem-Imaje Corporation Symbol grouping and striping for wide field matrix laser marking

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