WO2000067945A1 - Device for removing material from workpieces by means of a laser beam - Google Patents
Device for removing material from workpieces by means of a laser beam Download PDFInfo
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- WO2000067945A1 WO2000067945A1 PCT/DE2000/001383 DE0001383W WO0067945A1 WO 2000067945 A1 WO2000067945 A1 WO 2000067945A1 DE 0001383 W DE0001383 W DE 0001383W WO 0067945 A1 WO0067945 A1 WO 0067945A1
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- laser
- pulse
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Classifications
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- 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
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- 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
- B23K26/36—Removing material
- B23K26/38—Removing material by boring or cutting
- B23K26/382—Removing material by boring or cutting by boring
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- 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
- B23K26/36—Removing material
- B23K26/40—Removing material taking account of the properties of the material involved
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- 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
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/50—Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
Definitions
- the invention relates to a device for removing material from a workpiece by means of a laser beam with the features of the preamble of the independent claims.
- Such a device usually comprises a laser arrangement for generating a laser beam from at least one laser pulse, which has parameter values at least for laser wavelength, pulse duration, pulse spacing and laser intensity.
- Devices of this type are used in particular to drill holes with the highest precision in a workpiece.
- the invention is described below with reference to a laser drilling device, it is clear that the measures according to the invention can also be applied to other devices which cause a precise material removal by means of a laser beam on a workpiece, regardless of whether this material removal takes the form of a drilling, Milling or cutting process or the like. he follows.
- the material When a laser hole is formed, the material is removed or expelled by liquefaction and evaporation at the point of impact of the laser beam.
- the precision of such a laser drilling is incomplete expelled material, which mainly deposits as a melt in the borehole, is significantly impaired.
- the laser intensity can be increased to improve the material output. This increases the vapor pressure generated by the laser beam and thus also the material output. However, an increased vapor pressure also results in an increased shielding of the laser beam, which reduces the drilling speed and the maximum achievable drilling depth.
- the device according to the invention in particular if it is designed as a laser drilling device for machining workpieces made of solid material, has the advantage that the laser system works with at least two types of laser pulses, one type of laser pulse being selected by a suitable choice of its parameter values, e.g. when drilling, with regard to a maximum drilling depth and
- Drilling speed is designed, while the other laser pulse type is optimized by a corresponding selection of its parameter values, for example when drilling with regard to a maximum material output.
- the at least two types of laser pulses can be matched to one another in such a way that, for example in the case of a laser drilling device, there are optimal values for the maximum achievable drilling depth, for the drilling speed and for the precision of the drilling.
- the invention is based on the knowledge that e.g. in laser drilling, the values for drilling depth, drilling progress and drilling quality depend particularly strongly on certain parameter values of the laser pulse. The important ones
- Parameter values are laser wavelength and pulse duration.
- an interaction of electromagnetic radiation with a plasma present in the borehole increases with the laser wavelength; the interaction increases proportionally to the square of the laser wavelength.
- a larger laser wavelength has a stronger interaction with the plasma and thus causes a greater plasma formation and e ne greater pressure increase in the plasma, while a shorter laser wavelength forms less plasma and also passes through the plasma relatively unhindered.
- a shorter laser wavelength therefore results in a higher drilling speed and a greater maximum drilling depth, while a larger laser wavelength improves the drilling quality.
- the laser arrangement can be designed such that it generates a laser beam in which at least one laser pulse of one type follows at least one laser pulse of the other type. In this way, for example, when laser drilling
- Drilling phases with high drilling speed and drilling phases with strong material drive can be generated with the help of a single laser beam.
- the laser arrangement can be designed such that it generates two coaxial laser beams, one of which consists of at least one laser pulse of one type and the other of at least one laser pulse of the other type. In this way, one laser beam causes a high drilling speed and the other laser beam produces a high drilling quality.
- the laser arrangement can have two laser generators or lasers, one of which generates a laser beam with at least one laser pulse of one type and the other generates a laser beam with at least one laser pulse of the other type, the laser arrangement then also having an optical arrangement which interconnects the lasers and aligns their laser beams coaxially.
- Laser arrangements e.g. optimized either to achieve a high drilling speed or to achieve a high drilling precision, can be put together to form the device according to the invention, which uses the advantages of both lasers.
- the pulse duration of at least one of the laser pulse types can be approximately as long as the time required to carry out a material removal process, in particular a drilling.
- FIG. 1 is a circuit diagram-like Pzip view of a device according to the invention in a first embodiment
- Fig. 2 is a circuit diagram-like P ⁇ nzipdargna the
- a laser arrangement 1 m in a first embodiment according to FIG. 1 has a pulsed laser 2 suitable for drilling, which in particular can be a well-switched solid-state laser.
- This laser 2 generates a laser beam 3, which is symbolized by a solid line.
- This laser beam 3 is constructed from laser pulses that have a specific laser wavelength
- this laser wavelength is 1064 nm, which is the fundamental wavelength of this laser type
- the laser beam 3 is fed to a frequency multiplier 4, m the laser pulse by frequency multiplication can be generated with a shorter laser wavelength.
- a frequency multiplier 4 usually consists of a crystal or of crystals that generate at least one associated harmonic wavelength from a fundamental wavelength.
- the shorter laser wavelength is thus preferably a harmonic wavelength to the fundamental wavelength of the respective laser type; with an Nd: YAG aser, the harmonic wavelengths are, for example, 532 nm, 355 nm, 266 nm shorter laser wavelength can be used.
- From the frequency multiplier 4 there emerges a first laser beam 5, shown with a solid line, the laser pulses of which have a longer laser wavelength, and a second laser beam 6, shown with a broken line, whose laser pulses have a shorter laser wavelength.
- the laser beams 5 and 6 strike a first splitter mirror 7, which consists, for example, of a dielectric coated glass plate and has a high transmission for the longer laser wavelength and a high reflection for the shorter laser wavelength.
- a beam interrupter 8 or 9 is arranged, for example by a mechanical interrupter, a so-called “chopper” or from an electrically controllable one
- Beam switches eg Pockels cell
- the two laser beams 5 and 6 are brought together again via a second splitter mirror 10 and aligned coaxially to one another.
- the second divider mirror 10 also preferably consists of a dielectrically coated glass plate with high transmission for the larger laser wavelength and high reflection for the smaller laser wavelength.
- laser pulses of one type can alternate with laser pulses of the other type (e.g. with a shorter laser wavelength). It is also possible to alternate a series of laser pulses of one type with a series of laser pulses of the other type. For a specific application, it can also be expedient to let the two laser beams 5 and 6 or their laser pulses strike the respective workpiece simultaneously.
- a laser arrangement 11 in a device according to the invention is equipped with a pulsed laser 12 suitable for drilling, preferably with a solid-state laser, which has a resonator 13, in which a laser crystal 19 is arranged, for example is designed as a rod crystal or slab stall.
- a first Brewster window 14 and a second Brewster window 15 are arranged in a resonator 13 of the laser arrangement on both sides of the laser 12, with the aid of which a linear polarization of the laser beam generated by the laser 12 is carried out.
- a Pockels cell 16 is also arranged in the resonator 13, which is switched free running for laser pulses with a predetermined longer pulse duration and works as a good switch for laser pulses with a predetermined shorter pulse duration.
- the long pulse duration can be 150 ⁇ s, for example, while the short pulse duration is 10 ns, for example.
- an end mirror 17 and a coupling-out mirror 18 are arranged in the resonator 13.
- the Brewster windows 14 and 15 are not required.
- another suitable Q-switch can also be used. It is also possible to construct the device 11 with different laser wavelengths in order to adapt the coupling for shifted materials. In the device 11 according to FIG. 2, the laser excitation can take place both with flash lamps and with diodes.
- the laser arrangement 11 can be operated in accordance with a second exemplary embodiment in such a way that laser pulses with a long pulse duration and laser pulses with a short pulse duration alternate.
- a series of laser pulses of one type e.g. with a long one
- Pulse duration follow a series of laser pulses of the other type (eg with a short pulse duration).
- the pulse duration of one laser pulse type is at least a factor IO 3 greater or smaller than the pulse duration of the other laser pulse type. In this way, it is possible in particular to rapidly advance the hole to be drilled into a workpiece in a workpiece during a first drilling phase with laser pulses with the longer pulse duration and to clean or close this hole during a second drilling phase with laser pulses with the short pulse duration specify.
- the laser arrangement 11 superimposes different laser wavelengths on the different pulse durations.
- different laser wavelengths can be applied to the different pulse durations.
- the respective laser arrangement has at least two laser systems, each of which generates a laser beam with a laser pulse type, the parameter values of the laser pulses in the laser systems being different.
- Such a laser arrangement then has a corresponding optical arrangement in order to align the different laser beams coaxially with one another.
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- Mechanical Engineering (AREA)
- Laser Beam Processing (AREA)
- Lasers (AREA)
Abstract
Description
Vorrichtung zum Materialabtragen bei Werkstücken mittels LaserstrahlDevice for removing material from workpieces using a laser beam
Stand der TechnikState of the art
Die Erfindung betrifft eine Vorrichtung zum Abtragen von Material bei einem Werkstück mittels eines Laserstrahles mit den Merkmalen des Oberbegriffes der unabhängigen Ansprüche.The invention relates to a device for removing material from a workpiece by means of a laser beam with the features of the preamble of the independent claims.
Eine derartige Vorrichtung umfaßt üblicherweise eine Laseranordnung zur Erzeugung eines Laserstrahles aus wenigstens einem Laserpuls, der Parameterwerte zumindest für Laserwellenlänge, Pulsdauer, Pulsabstand und Laserintensität aufweist .Such a device usually comprises a laser arrangement for generating a laser beam from at least one laser pulse, which has parameter values at least for laser wavelength, pulse duration, pulse spacing and laser intensity.
Vorrichtungen dieser Art werden insbesondere dazu verwendet, in einem Werkstück Bohrungen mit höchster Präzision auszubilden. Obwohl die Erfindung im folgenden mit Bezug auf eine Laserbohrvorrichtung beschrieben ist, ist klar, daß die erfindungsgemäßen Maßnahmen auch bei anderen Vorrichtungen anwendbar sind, die mittels Laserstrahl bei einem Werkstück eine präzise Materialabtragung bewirken, unabhängig davon, ob diese Materialabtragung nach Art eines Bohr-, Fräs- oder Schneidvorganges od.dgl. erfolgt.Devices of this type are used in particular to drill holes with the highest precision in a workpiece. Although the invention is described below with reference to a laser drilling device, it is clear that the measures according to the invention can also be applied to other devices which cause a precise material removal by means of a laser beam on a workpiece, regardless of whether this material removal takes the form of a drilling, Milling or cutting process or the like. he follows.
Beim Ausbilden einer Laserbohrung wird an der Auftreffstelle des Laserstrahls das Material durch Verflüssigung und Verdampfung abgetragen bzw. ausgetrieben. Die Präzision einer derartigen Laserbohrung wird durch unvollständig ausgetriebenes Material, das sich vor allem als Schmelze im Bohrloch ablagert, erheblich beeinträchtigt. Um den Materialaustrieb zu verbessern, kann die Lasermtensitat gesteigert werden. Dadurch erhöht sich der durch den Laserstrahl erzeugte Dampfdruck und damit auch der Mateπalaustrieb . Ein erhöhter Dampfdruck bewirkt jedoch gleichzeitig eine verstärkte Abschirmung des Laserstrahls, wodurch sich die Bohrgeschwindigkeit sowie die maximal erreichbare Bohrtiefe reduzieren.When a laser hole is formed, the material is removed or expelled by liquefaction and evaporation at the point of impact of the laser beam. The precision of such a laser drilling is incomplete expelled material, which mainly deposits as a melt in the borehole, is significantly impaired. The laser intensity can be increased to improve the material output. This increases the vapor pressure generated by the laser beam and thus also the material output. However, an increased vapor pressure also results in an increased shielding of the laser beam, which reduces the drilling speed and the maximum achievable drilling depth.
Dieser Zusammenhang wird damit begründet, daß sich beim Laserbohren im Bohrloch Plasma bildet, das die Laserstrahlung teilweise absorbiert und somit abschwächt, so daß sich die Bohrgeschwindigkeit und die maximal erreichbare Bohrtiefe verringern. Gleichzeitig wird das Plasma durch das teilweise Absorbieren des Laserstrahls erwärmt, wodurch sich im Plasma der Druck erhöht, was dazu führt, daß sich der Mater alaustrieb und somit die Bohrpräzision verbessert. Außerdem bewirkt das Plasma eine Glättung und Aufweitung der Bohrungswandung.This relationship is justified by the fact that during laser drilling, plasma forms in the borehole, which partially absorbs the laser radiation and thus weakens it, so that the drilling speed and the maximum achievable drilling depth decrease. At the same time, the plasma is heated by the partial absorption of the laser beam, which increases the pressure in the plasma, which means that the material expels and thus improves the drilling precision. In addition, the plasma smoothes and widens the wall of the hole.
Vorteile der ErfindungAdvantages of the invention
Die erfindungsgemäße Vorrichtung, insbesondere wenn sie als Laserbohrvorπchtung zum Bearbeiten von Werkstücken aus massivem Material ausgebildet ist, hat demgegenüber den Vorteil, daß die Laseranlage mit wenigstens zwei Typen von Laserpulsen arbeitet, wobei der eine Laserpulstyp durch eine geeignete Wahl seiner Parameterwerte, z.B. beim Bohren, hinsichtlich einer maximalen Bohrtiefe undThe device according to the invention, in particular if it is designed as a laser drilling device for machining workpieces made of solid material, has the advantage that the laser system works with at least two types of laser pulses, one type of laser pulse being selected by a suitable choice of its parameter values, e.g. when drilling, with regard to a maximum drilling depth and
Bohrgeschwindigkeit ausgelegt ist, während der andere Laserpulstyp durch eine entsprechende Auswahl seiner Parameterwerte, z.B. beim Bohren hinsichtlich eines maximalen Materialaustπebes optimiert ist . Die wenigstens zwei Laserpulstypen können daoei so aufeinander abgestimmt werden, daß sich .beispielsweise bei einer Laserbohrvorrichtung optimale Werte für die maximal erreichbare Bohrtiefe, für die Bohrgeschwindigkeit und für die Präzision der Bohrung ergeben.Drilling speed is designed, while the other laser pulse type is optimized by a corresponding selection of its parameter values, for example when drilling with regard to a maximum material output. The at least two types of laser pulses can be matched to one another in such a way that, for example in the case of a laser drilling device, there are optimal values for the maximum achievable drilling depth, for the drilling speed and for the precision of the drilling.
Die Erfindung beruht dabei auf der Erkenntnis, daß z.B. beim Laserbohren die Werte für Bohrtiefe, Bohrfortschritt und Bohrqualität von bestimmten Parameterwerten des Laserpulses besonders stark abhängen. Die insoweit wichtigenThe invention is based on the knowledge that e.g. in laser drilling, the values for drilling depth, drilling progress and drilling quality depend particularly strongly on certain parameter values of the laser pulse. The important ones
Parameterwerte sind Laserwellenlange und Pulsdauer.Parameter values are laser wavelength and pulse duration.
Beispielsweise nimmt eine Wechselwirkung elektromagnetischer Strahlung mit einem im Bohrloch vorhandenen Plasma mit der Laserwellenlänge zu; die Wechselwirkung nimmt dabei proportional zum Quadrat der Laserwellenlänge zu. Das bedeutet, daß eine größere Laserwellenlänge eine stärkere Wechselwirkung mit dem Plasma aufweist und somit eine stärkere Plasmabildung sowie e ne größere Druckerhöhung im Plasma bewirkt, während eine kürzere Laserwellenlänge weniger Plasma bildet und außerdem relativ ungehindert durch das Plasma hindurchtritt. Somit bewirkt eine kürzere Laserwellenlänge eine höhere Bohrgeschwindigkeit sowie eine größere maximale Bohrtiefe, während eine größere Laserwellenlänge die Bohrqualität verbessert.For example, an interaction of electromagnetic radiation with a plasma present in the borehole increases with the laser wavelength; the interaction increases proportionally to the square of the laser wavelength. This means that a larger laser wavelength has a stronger interaction with the plasma and thus causes a greater plasma formation and e ne greater pressure increase in the plasma, while a shorter laser wavelength forms less plasma and also passes through the plasma relatively unhindered. A shorter laser wavelength therefore results in a higher drilling speed and a greater maximum drilling depth, while a larger laser wavelength improves the drilling quality.
Ein ähnlicher Zusammenhang ergibt sich durch die Auswahl der Pulsdauer, insbesondere m Verbindung m t einer damit abgestimmten Laserintensität . Während eine längere Pulsdauer selbst bei geringerer Laserintensität einen schnelleren Bohrfortschritt bewirkt und dabei weniger Plasma bildet, sorgt eine kürzere Pulsdauer, insbesondere bei höherer Laserintensität, für eine stärkere Plasmabildung, die Ablagerungen auf der Bohrungswand verhindert bzw. beseitigt, wodurch sich die Bohrprazision erhöht. Entsprechend einer vorteilhaften Ausfuhrungsform kann die Laseranordnung so ausgestaltet sein, daß sie einen Laserstrahl erzeugt, bei dem mindestens ein Laserpuls des einen Typs auf wenigstens einen Laserpuls des anαeren Typs folgt. Auf diese Weise können z.B. beim LaserbohrenA similar relationship arises from the selection of the pulse duration, in particular in connection with a laser intensity coordinated therewith. While a longer pulse duration leads to faster drilling progress and less plasma, even with a lower laser intensity, a shorter pulse duration, especially with higher laser intensity, ensures stronger plasma formation, which prevents or eliminates deposits on the bore wall, which increases drilling precision. According to an advantageous embodiment, the laser arrangement can be designed such that it generates a laser beam in which at least one laser pulse of one type follows at least one laser pulse of the other type. In this way, for example, when laser drilling
Bohrphasen mit hoher Bohrgeschwindigkeit und Bohrphasen mit starkem Mateπalaustrieb mit Hilfe eines einzigen Laserstrahls erzeugt werden.Drilling phases with high drilling speed and drilling phases with strong material drive can be generated with the help of a single laser beam.
Bei einer Variante kann die Laseranordnung so ausgestaltet sein, daß sie zwei koaxiale Laserstrahlen erzeugt, von denen der eine aus wenigstens einem Laserpuls des einen Typs und der andere aus wenigstens einem Laserpuls des anderen Typs besteht. Auf diese Weise bewirkt der eine Laserstrahl eine hohe Bohrgeschwindigkeit und der andere Laserstrahl eine hohe Bohrqualität .In a variant, the laser arrangement can be designed such that it generates two coaxial laser beams, one of which consists of at least one laser pulse of one type and the other of at least one laser pulse of the other type. In this way, one laser beam causes a high drilling speed and the other laser beam produces a high drilling quality.
Bei einer anderen Ausfuhrungsform kann die Laseranordnung zwei Lasergeneratoren oder Laser aufweisen, von denen der eine einen Laserstrahl mit mindestens einem Laserpuls des einen Typs und der andere einen Laserstrahl mit mindestens einem Laserpuls des anderen Typs erzeugt, wobei die Laseranordnung dann auch eine Optikanordnung aufweist, die die Laser zusammenschaltet und deren Laserstrahlen koaxial ausrichtet. Durch diese Maßnahmen können bestehendeIn another embodiment, the laser arrangement can have two laser generators or lasers, one of which generates a laser beam with at least one laser pulse of one type and the other generates a laser beam with at least one laser pulse of the other type, the laser arrangement then also having an optical arrangement which interconnects the lasers and aligns their laser beams coaxially. Through these measures, existing
Laseranordnungen, die z.B. entweder zur Erzielung einer hohen Bohrgeschwindigkeit oder zur Erzielung einer hohen Bohrpräzision optimiert sind, zur erfindungsgemäßen Vorrichtung zusammengesetzt werden, die die Vorteile beider Laser nutzt.Laser arrangements, e.g. optimized either to achieve a high drilling speed or to achieve a high drilling precision, can be put together to form the device according to the invention, which uses the advantages of both lasers.
Bei einer besonderen Ausfuhrungsform kann die Pulsdauer wenigstens eines der Laserpulstypεn etwa so groß sein wie die Zeitdauer, die zur Durchführung eines Materialabtragungsvorganges, insbesondere einer Bohrung, erforderlich ist. Weitere wichtige Merkmale und Vorteile der erfmdungsgemaßen Vorrichtung ergeben sicn aus den Unteranspruchen, aus den Zeichnungen und aus der zugehörigen Figurenbeschreibung anhand der ZeichnungenIn a special embodiment, the pulse duration of at least one of the laser pulse types can be approximately as long as the time required to carry out a material removal process, in particular a drilling. Further important features and advantages of the device according to the invention result from the subclaims, from the drawings and from the associated description of the figures with reference to the drawings
Zeichnungdrawing
Ausfuhrungsbeispiele der erfmdungsgemaßen Vorricntung sind m den Zeichnungen dargestellt und werden m folgenden naher erläutert Es zeigen, jeweils schematisch,Exemplary embodiments of the device according to the invention are shown in the drawings and are explained in more detail in the following.
Fig. 1 eine schaltplanartige Pπnzipdarstellung einer Vorrichtung nach der Erfindung m einer ersten Ausführungsform und1 is a circuit diagram-like Pzip view of a device according to the invention in a first embodiment and
Fig. 2 eine schaltplanartige Pπnzipdarstellung derFig. 2 is a circuit diagram-like Pπnzipdarstellung the
Vorrichtung nach der Erfindung m einer zweiten Ausfuhrungsform.Device according to the invention in a second embodiment.
AusfuhrungsbeispielePractical examples
Entsprechend Fig. 1 weist bei einer als Laserbohrvorrichtung ausgebildeten Vorrichtung nach der Erfindung eine Laseranordnung 1 m einer ersten Ausführungsform entsprechend Fig. 1 einen zum Bohren geeigneten gepulsten Laser 2 auf, der insbesondere ein gutegeschalteter Festkörperlaser sein kann. Dieser Laser 2 generiert einen Laserstrahl 3, der durch eine durchgezogene Linie symbolisiert ist. Dieser Laserstrahl 3 ist aus Laserpulsen aufgebaut, die eine bestimmte Laserwellenlange aufweisenAccording to FIG. 1, in a device designed as a laser drilling device according to the invention, a laser arrangement 1 m in a first embodiment according to FIG. 1 has a pulsed laser 2 suitable for drilling, which in particular can be a well-switched solid-state laser. This laser 2 generates a laser beam 3, which is symbolized by a solid line. This laser beam 3 is constructed from laser pulses that have a specific laser wavelength
Beispielsweise betragt diese Laserwellenlange bei einem Nd:YAG-Laser 1064 nm, das ist die Grundwellenlangε dieses Laser-TypsFor example, in the case of an Nd: YAG laser, this laser wavelength is 1064 nm, which is the fundamental wavelength of this laser type
Der Laserstrahl 3 wird einem Frequenzvervielfacher 4 zugeleitet, m dem durch Frequenzvervielfachung Laserpulse mit einer kürzeren Laserwellenlange erzeugt werden. Ein Frequenzvervielfacher 4 besteht üblicherweise aus einem Kristall oder aus Kristallen, die aus einer Grundwellenlange wenigstens eine zugehörige harmonische Wellenlange erzeugen. Die kürzere Laserwellenlange ist somit vorzugsweise eine harmonische Wellenlange zur Grundwellenlange des jeweiligen Laser-Typs ; bei einem Nd:YAG- aser betragen d e harmonischen Wellenlangen z.B. 532 nm, 355 nm, 266 nm. Anstelle der Grundwellenlange als längere Laserwellenlange und einer harmonischen Wellenlange als kürzere Laserwellenlange können auch eine harmonische Wellenlange als längere Laserwellenlange und eine der darauf folgenden harmonische Wellenlange als kürzere Laserwellenlange verwendet werden. Aus dem Frequenzvervielfacher 4 tritt somit ein mit durchgezogener Linie dargestellter erster Laserstrahl 5 aus, dessen Laserpulse eine größere Laserwellenlange aufweisen, sowie ein mit unterbrochener Linie dargestellter zweiter Laserstrahl 6, dessen Laserpulse eine kürzere Laserwellenlänge aufweisen.The laser beam 3 is fed to a frequency multiplier 4, m the laser pulse by frequency multiplication can be generated with a shorter laser wavelength. A frequency multiplier 4 usually consists of a crystal or of crystals that generate at least one associated harmonic wavelength from a fundamental wavelength. The shorter laser wavelength is thus preferably a harmonic wavelength to the fundamental wavelength of the respective laser type; with an Nd: YAG aser, the harmonic wavelengths are, for example, 532 nm, 355 nm, 266 nm shorter laser wavelength can be used. From the frequency multiplier 4 there emerges a first laser beam 5, shown with a solid line, the laser pulses of which have a longer laser wavelength, and a second laser beam 6, shown with a broken line, whose laser pulses have a shorter laser wavelength.
Nach dem Frequenzvervielfacher 4 treffen die Laserstrahlen 5 und 6 auf einen ersten Teilerspiegel 7, der beispielsweise aus einer dielektrisch beschichteten Glasplatte besteht und eine hohe Transmission für die längere Laserwellenlange und eine hohe Reflexion für die kürzere Laserwellenlange aufweist. In den durch den Teilerspiegel 7 getrennten Strahlwegen der beiden Laserstrahlen 5 und 6 ist jeweils ein Strahlunterbrecher 8 bzw. 9 angeordnet, d e beispielsweise durch einen mechanischen Unterbrecher, einen sogenannten „Chopper" oder aus einem elektrisch ansteuerbarenAfter the frequency multiplier 4, the laser beams 5 and 6 strike a first splitter mirror 7, which consists, for example, of a dielectric coated glass plate and has a high transmission for the longer laser wavelength and a high reflection for the shorter laser wavelength. In each of the beam paths of the two laser beams 5 and 6, which are separated by the splitter mirror 7, a beam interrupter 8 or 9 is arranged, for example by a mechanical interrupter, a so-called “chopper” or from an electrically controllable one
Strahlschalter , z.B. Pockelszelle , gebildet sind. Nach den Strahlunterbrechern 8 und 9 werden die beiden Laserstrahlen 5 und 6 über einen zweiten Teilerspiegel 10 wieder zusammengeführt und koaxial zueinander ausgerichtet. Auch der zweite Teilerspiegel 10 besteht vorzugsweise aus einer dielektrisch beschichteten Glasplatte mit hoher Transmission f r die größere Laserwellenlange und hoher Reflexion für die kleinere Laserwellenlange.Beam switches, eg Pockels cell, are formed. After the beam breakers 8 and 9, the two laser beams 5 and 6 are brought together again via a second splitter mirror 10 and aligned coaxially to one another. The second divider mirror 10 also preferably consists of a dielectrically coated glass plate with high transmission for the larger laser wavelength and high reflection for the smaller laser wavelength.
Durch eine entsprechende Betätigung der Strahlunterbrecnεr 8 und 9 können beispielsweise Laserpulse des einen Typs (z.B mit größerer Laserwellenlange) mit Laserpulsen des anderen Typs (z.B mit kürzerer Laserwellenlange) einander abwechseln. Ebenso ist es möglich, eine Serie von Laserpulsen des einen Typs mit einer Serie von Laserpulsen des anderen Typs abzuwechseln. Für eine bestimmte Anwendung kann es auch zweckmäßig sein, die beiden Laserstrahlen 5 und 6 bzw. deren Laserpulse gleichzeitig am jeweiligen Werkstück auftreffen zu lassen.By correspondingly actuating the beam interrupters 8 and 9, for example, laser pulses of one type (e.g. with a longer laser wavelength) can alternate with laser pulses of the other type (e.g. with a shorter laser wavelength). It is also possible to alternate a series of laser pulses of one type with a series of laser pulses of the other type. For a specific application, it can also be expedient to let the two laser beams 5 and 6 or their laser pulses strike the respective workpiece simultaneously.
Entsprechend Fig. 2 ist eine Laseranordnung 11 bei einer ebenfalls als Laserbohrvorrichtung ausgebildeten Vorrichtung nach der Erfindung mit einem zum Bohren geeigneten gepulsten Laser 12, vorzugsweise mit einem Festkörperlaser, ausgestattet, der einen Resonator 13 aufweist, m dem ein Laserkristall 19 angeordnet ist, das beispielsweise als Rod- Kristall oder Slab-Kπstall ausgebildet ist. In einem Resonator 13 der Laseranordnung sind beiderseits des Lasers 12 ein erstes Brewsterfenster 14 sowie ein zweites Brewsterfenster 15 angeordnet, mit deren Hilfe eine lineare Polarisation des vom Laser 12 erzeugten Laserstrahles durchgeführt wird. Im Resonator 13 ist außerdem eine Pockelszelle 16 angeordnet, die für Laserpulse mit einer vorgegebenen längeren Pulsdauer freilaufend geschaltet ist und für Laserpulse mit einer vorbestimmter kürzeren Pulsdauer als Guteschalter arbeitet. Die lange Pulsdauer kann beispielsweise 150 μs betragen, wahrend die kurze Pulsdauer beispielsweise 10 ns betragt.2, a laser arrangement 11 in a device according to the invention, also designed as a laser drilling device, is equipped with a pulsed laser 12 suitable for drilling, preferably with a solid-state laser, which has a resonator 13, in which a laser crystal 19 is arranged, for example is designed as a rod crystal or slab stall. A first Brewster window 14 and a second Brewster window 15 are arranged in a resonator 13 of the laser arrangement on both sides of the laser 12, with the aid of which a linear polarization of the laser beam generated by the laser 12 is carried out. A Pockels cell 16 is also arranged in the resonator 13, which is switched free running for laser pulses with a predetermined longer pulse duration and works as a good switch for laser pulses with a predetermined shorter pulse duration. The long pulse duration can be 150 μs, for example, while the short pulse duration is 10 ns, for example.
Des weiteren sind m Resonator 13 ein Endspiegel 17 sowie ein Auskoppelspiegel 18 angeordnet. Bei einer Ausführung mit einem Slab-Kristall sind die Brewsterfenster 14 und 15 nicht erforderlich. Anstelle einer Pockelszelle 16 kann auch ein anderer geeigneter Güteschalter verwendet werden. Außerdem ist es möglich, die Vorrichtung 11 mit unterschiedlichen Laserwellenlangen aufzubauen, um die Emkopplung für verschiebene Materialien anzupassen. Bei der Vorrichtung 11 gemäß Fig. 2 kann die Laseranregung sowohl mit Blitzlampen als auch mit Dioden erfolgen.Furthermore, an end mirror 17 and a coupling-out mirror 18 are arranged in the resonator 13. In a version with a slab crystal, the Brewster windows 14 and 15 are not required. Instead of a Pockels cell 16, another suitable Q-switch can also be used. It is also possible to construct the device 11 with different laser wavelengths in order to adapt the coupling for shifted materials. In the device 11 according to FIG. 2, the laser excitation can take place both with flash lamps and with diodes.
Zur Durchführung einer Laserbohrung kann gemäß einem zweiten Ausführungsbeispiel die Laseranordnung 11 so betrieben werden, daß sich Laserpulse mit langer Pulsdauer und Laserpulse mit kurzer Pulsdauer abwechseln. Ebenso kann eine Serie von Laserpulsen des einen Typs (z.B. mit langerTo carry out a laser drilling, the laser arrangement 11 can be operated in accordance with a second exemplary embodiment in such a way that laser pulses with a long pulse duration and laser pulses with a short pulse duration alternate. Likewise, a series of laser pulses of one type (e.g. with a long one
Pulsdauer) auf eine Serie von Laserpulsen des anderen Typs (z.B. mit kurzer Pulsdauer) folgen. Die Pulsdauer des einen Laserpulstyps ist dabei wenigsten um einen Faktor IO3 großer oder kleiner als die Pulsdauer des anderen Laserpulstyps. Auf diese Weise ist es insbesondere möglich, während einer ersten Bohrphase mit Laserpulsen mit der längeren Pulsdauer in einem Werkstück die darin einzubringende Bohrung rasch bis zu einer gewünschten Bohrtiefe voranzutreiben und während einer zweiten Bohrphase mit Laserpulsen mit der kurzen Pulsdauer diese Bohrung zu säubern bzw. zu präzisieren.Pulse duration) follow a series of laser pulses of the other type (eg with a short pulse duration). The pulse duration of one laser pulse type is at least a factor IO 3 greater or smaller than the pulse duration of the other laser pulse type. In this way, it is possible in particular to rapidly advance the hole to be drilled into a workpiece in a workpiece during a first drilling phase with laser pulses with the longer pulse duration and to clean or close this hole during a second drilling phase with laser pulses with the short pulse duration specify.
Weiterhin ist ein Ausführungsbeispiel möglich, bei dem die Laseranordnung 11 den unterschiedlichen Pulsdauern unterschiedliche Laserwellenlängen überlagert. Außerdem können die unterschiedlichen Pulsdauern mit unterschiedlichen Laserwellenlängen beaufschlagt werden.Furthermore, an exemplary embodiment is possible in which the laser arrangement 11 superimposes different laser wavelengths on the different pulse durations. In addition, different laser wavelengths can be applied to the different pulse durations.
Im Unterschied zu den gezeigten Ausführungsbeispielen, in denen die Laserstrahlen mit sich in ihren Parameterwerten unterscheidenden Laserpulsen innerhalb eines Lasersystems erzeugt werden, sind auch andere Ausführungsformen möglich, bei der die jeweilige Laseranordnung wenigstens zwei Lasersysteme aufweist, die jeweils einen Laserstranl mit einem Laserpulstyp erzeugen, wobei sicn die Parameterwerte der Laserpulse bei den Lasersystemen unterscheiden. Eine solche Laseranordnung weist dann eine entsprechende Optikanordnung auf, um die unterschiedlicnen Laserstrahlen koaxial zueinander auszurichten. In contrast to the exemplary embodiments shown, in which the laser beams with laser pulses differing in their parameter values within a laser system Other embodiments are also possible in which the respective laser arrangement has at least two laser systems, each of which generates a laser beam with a laser pulse type, the parameter values of the laser pulses in the laser systems being different. Such a laser arrangement then has a corresponding optical arrangement in order to align the different laser beams coaxially with one another.
Claims
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP00936661A EP1097021A1 (en) | 1999-05-06 | 2000-05-03 | Device for removing material from workpieces by means of a laser beam |
| JP2000616958A JP2002543984A (en) | 1999-05-06 | 2000-05-03 | Workpiece removal equipment using laser |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19920813.1 | 1999-05-06 | ||
| DE19920813A DE19920813A1 (en) | 1999-05-06 | 1999-05-06 | Device for removing material from workpieces using a laser beam |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2000067945A1 true WO2000067945A1 (en) | 2000-11-16 |
Family
ID=7907138
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/DE2000/001383 Ceased WO2000067945A1 (en) | 1999-05-06 | 2000-05-03 | Device for removing material from workpieces by means of a laser beam |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP1097021A1 (en) |
| JP (1) | JP2002543984A (en) |
| DE (1) | DE19920813A1 (en) |
| WO (1) | WO2000067945A1 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GR20020100116A (en) * | 2002-03-01 | 2003-11-17 | Ιδρυμα Τεχνολογιας Και Ερευνας (Ι.Τ.Ε.) | Method and system for cleaning surfaces with the use of laser pulses of two different wavelengths |
| EP1389158B1 (en) * | 2001-05-24 | 2005-08-03 | Advanced Dicing Technologies Ltd. | Dual laser cutting of wafers |
| DE10119033B4 (en) * | 2001-04-18 | 2005-11-03 | Robert Bosch Gmbh | Method for balancing a resonator in an oscillator |
| WO2006024585A1 (en) * | 2004-09-02 | 2006-03-09 | Hitachi Via Mechanics, Ltd. | Laser light source, method for machining workpieces by means of pulsed laser radiation |
| EP3335900A1 (en) * | 2016-12-13 | 2018-06-20 | Giesecke+Devrient Currency Technology GmbH | Laser cutting and laser discolouration of security documents |
| WO2018162356A1 (en) * | 2017-03-07 | 2018-09-13 | Robert Bosch Gmbh | Method and device for shaping radiation for laser processing |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| DE10358927B4 (en) | 2003-12-16 | 2021-09-09 | Carl Zeiss Meditec Ag | Laser device and method for material processing by means of laser radiation |
| DE102004013475B4 (en) * | 2004-03-18 | 2007-01-25 | Lasertec Gmbh | Method and device for removing material |
| JP2005338137A (en) * | 2004-05-24 | 2005-12-08 | Yokogawa Electric Corp | Laser light source device |
| DE102007062182A1 (en) | 2007-12-21 | 2009-06-25 | Robert Bosch Gmbh | Injection valve for injecting fuel, into mixture processing apparatus in fuel injection or exhaust system of internal-combustion engine, has blowhole formed in ceramic body using laser which transmits pulses with extremely small pulse time |
| DE102011000768B4 (en) * | 2011-02-16 | 2016-08-18 | Ewag Ag | Laser processing method and laser processing apparatus with switchable laser arrangement |
| CN109044526B (en) * | 2018-07-03 | 2024-05-07 | 瑞尔通(苏州)医疗科技有限公司 | Dual wavelength laser and laser therapeutic instrument |
| CN113210856B (en) * | 2021-04-22 | 2022-07-19 | 广东工业大学 | PCB short-wavelength pulse laser drilling method and related drilling device |
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- 2000-05-03 JP JP2000616958A patent/JP2002543984A/en active Pending
- 2000-05-03 EP EP00936661A patent/EP1097021A1/en not_active Withdrawn
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| WO1986002301A1 (en) * | 1984-10-16 | 1986-04-24 | Advanced Laser Systems, Inc. | Laser drilling apparatus and method |
| DE4207169A1 (en) * | 1992-03-06 | 1993-09-09 | Siemens Solar Gmbh | Laser operations on a workpiece with uneven surface - where distances between workpiece and laser are measured during intervals between working pulses |
| US5635089A (en) * | 1993-07-13 | 1997-06-03 | University Of Florida | Ceramic, metal and composite materials having increased surface area |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10119033B4 (en) * | 2001-04-18 | 2005-11-03 | Robert Bosch Gmbh | Method for balancing a resonator in an oscillator |
| US7148762B2 (en) | 2001-04-18 | 2006-12-12 | Robert Bosch Gmbh | Method for adjusting a resonator in an oscillator |
| EP1389158B1 (en) * | 2001-05-24 | 2005-08-03 | Advanced Dicing Technologies Ltd. | Dual laser cutting of wafers |
| GR20020100116A (en) * | 2002-03-01 | 2003-11-17 | Ιδρυμα Τεχνολογιας Και Ερευνας (Ι.Τ.Ε.) | Method and system for cleaning surfaces with the use of laser pulses of two different wavelengths |
| EP1340556A3 (en) * | 2002-03-01 | 2003-12-17 | Foundation for Research and Technology-Hellas (FO.R.T.H.), Institute of Electronic Structure and Laser | A method and device for cleaning surfaces using temporarily coincidental laser pulses of two different wavelengths |
| WO2006024585A1 (en) * | 2004-09-02 | 2006-03-09 | Hitachi Via Mechanics, Ltd. | Laser light source, method for machining workpieces by means of pulsed laser radiation |
| EP3335900A1 (en) * | 2016-12-13 | 2018-06-20 | Giesecke+Devrient Currency Technology GmbH | Laser cutting and laser discolouration of security documents |
| WO2018162356A1 (en) * | 2017-03-07 | 2018-09-13 | Robert Bosch Gmbh | Method and device for shaping radiation for laser processing |
| US11440136B2 (en) | 2017-03-07 | 2022-09-13 | Robert Bosch Gmbh | Method and device for shaping radiation for laser processing |
Also Published As
| Publication number | Publication date |
|---|---|
| DE19920813A1 (en) | 2001-06-28 |
| EP1097021A1 (en) | 2001-05-09 |
| JP2002543984A (en) | 2002-12-24 |
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