WO1993003882A1 - Appareil et procede permettant de surveiller un traitement par faisceau laser - Google Patents

Appareil et procede permettant de surveiller un traitement par faisceau laser Download PDF

Info

Publication number
WO1993003882A1
WO1993003882A1 PCT/GB1992/001555 GB9201555W WO9303882A1 WO 1993003882 A1 WO1993003882 A1 WO 1993003882A1 GB 9201555 W GB9201555 W GB 9201555W WO 9303882 A1 WO9303882 A1 WO 9303882A1
Authority
WO
WIPO (PCT)
Prior art keywords
nozzle
laser
sensor
workpiece
acoustic
Prior art date
Application number
PCT/GB1992/001555
Other languages
English (en)
Inventor
William Maxwell Steen
David Justin Brookfield
Lin Li
Original Assignee
Cmb Foodcan Plc
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 Cmb Foodcan Plc filed Critical Cmb Foodcan Plc
Publication of WO1993003882A1 publication Critical patent/WO1993003882A1/fr

Links

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
    • B23K26/12—Working by laser beam, e.g. welding, cutting or boring in a special atmosphere, e.g. in an enclosure
    • B23K26/123—Working by laser beam, e.g. welding, cutting or boring in a special atmosphere, e.g. in an enclosure in an atmosphere of particular gases
    • 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
    • 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
    • B23K26/14—Working by laser beam, e.g. welding, cutting or boring using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor
    • 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
    • B23K26/14—Working by laser beam, e.g. welding, cutting or boring using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor
    • B23K26/142—Working by laser beam, e.g. welding, cutting or boring using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor for the removal of by-products
    • 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
    • B23K26/14—Working by laser beam, e.g. welding, cutting or boring using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor
    • B23K26/1462—Nozzles; Features related to nozzles
    • B23K26/1464—Supply to, or discharge from, nozzles of media, e.g. gas, powder, wire
    • B23K26/1476—Features inside the nozzle for feeding the fluid stream through the nozzle

Definitions

  • the present invention relates to an apparatus and method for monitoring laser material processing.
  • a multitude of techniques have already been investigated for detecting the weld quality during processing. These include the use of an acoustic mirror which detects the high frequency component of back reflected laser beam from the beam material interaction zone; an acoustic probe which detects the shock wave generated by the plasma and vapour; an acoustic workpiece which detects the workpiece internal stress waves generated.during laser welding; a photo-electric sensor for detecting plasma intensity, a probe laser for detecting melt ripple and plasma diagnosis; a pyrometer for detecting the temperature near the melt pool, and a video camera for monitoring the interaction zone shape.
  • acoustic sensor includes sensors sensitive to vibration in the sonic or ultrasonic range of frequency.
  • the sensor signal is affected.
  • Acoustic probe by positioning a metal probe near the melt pool but not in contact with the workpiece and an acoustic sensor in contact with the other end of the probe, laser generated plasma or vapour shock waves can be detected which have been found to be indicative of processing quality.
  • the probe has been reported in three forms: a metal bar, a plate, and attaching an acoustic sensor on the focusing lens holder. In all three forms, the probe is coupled to the sensor directly and the probe is facing the melt pool. Therefore they are subject to laser reflection and melt pool heat radiation, which affect the sensing repeatability and reliability.
  • a secondary object is to provide a means of in- process monitoring of variations in workpiece distance from the laser.
  • an apparatus for monitoring laser material processing of a workpiece comprising an acoustic sensor which is mounted to a laser nozzle support assembly, the latter assembly being thermally insulated from the nozzle itself.
  • the thermal insulation is achieved by means of an annular member made of heat insulating material and disposed between the nozzle support assembly and the nozzle.
  • the apparatus further comprises a protective shield, having a hole for the laser beam to pass through, the shield being disposed between the sensor and a workpiece location for shielding the sensor from direct heat radiation.
  • FIG. 1 is a diagrammatic illustration of one embodiment of an apparatus in accordance with the present invention for monitoring laser material processing
  • Figs. 2a - 2c shows typical response patterns for an acoustic nozzle in accordance with the present invention for various high speed laser can weld faults
  • Fig. 3 shows typical response patterns for an acoustic nozzle in accordance with the present invention for various laser cut qualities.
  • the present invention uses a development of the type 3 acoustic probe discussed hereinbefore.
  • the sensor 10 e.g. a piezoelectric detector or some other ultrasonic detector
  • the nozzle 14 is mounted in the path of the laser beam 16 downstream of a lens arrangement 18 and is used in most laser processing applications for applying gas to the melt area of the workpiece for either shroud, lens protection, or gas assist for the process.
  • the lens arrangement 18 is mounted in a lens holder 20 to which gas is applied via a gas inlet duct 22.
  • the workpiece is indicated at 24.
  • a plasma and vapour "cloud" is generated in the region marked by the reference numeral 26.
  • a typical melt pool on the workpiece is indicated at 28.
  • the face of the sensor 10 is arranged to be attached to a flat surface on the nozzle support assembly 12, preferably with vacuum grease between the opposed surfaces. If the nozzle assembly does not already have a suitable flat surface, then the provision of such a surface can be achieved by, for example, machining a suitable surface directly on an existing component, or by fixing a metal collar with a suitable flat surface onto the nozzle support assembly. A mechanical clamping device may be used to fix the sensor 10 onto the flat surface.
  • the nozzle assembly 12 is thermally insulated from the nozzle 14.
  • the temperature of the nozzle 14 is likely to rise during laser processing since it is directly facing the melt pool and the sensor would be likely to be affected if a large part of this temperature rise was communicated to it.
  • the insulation is achieved by the use of an insulating member 30, e.g. a ceramics or
  • the plastics member 30 can, for example, be in the form of an annular sleeve or bush. Further thermal insulation of the sensor 10 is achieved by the provision of a plate 32 of metal or heat insulation material disposed between the sensor
  • the plate 32 has an aperture 34 through which the laser beam passes to the workpiece.
  • the plate 32 which can be flat (as shown) or in the form of a curved enclosure, prevents the radiation of the reflected laser beam and heat from the workpiece from reaching the sensor 10.
  • the plate or curved enclosure 32 is not in contact with the sensor 10 or the nozzle assembly 12 and may or may not be in contact with the nozzle itself.
  • the sensor output is coupled to an r.m.s. converter 36 via a pre-amp 38 and filter 40.
  • the r.m.s. converter output can be fed to a data-logger 42.
  • These particular circuit devices 40,36,42 are optional and others may be used depending on the information format required.
  • the sensor signal source is mainly gas generated impact of the workpiece.
  • the system therefore works on a completely different principle to the previous acoustic sensory units. It can be used as a distance sensor, proximity sensor and edge detector as well as for processing quality monitoring. Experiments have been performed to evaluate the present device. These experiments have indicated that:
  • the sensing operation is not affected by the heat radiation, so that therefore the device is robust and provides repeatable results.
  • the output signal is cleaner and stronger than in the case of the known acoustic mirror.
  • the sensing is non-contact and is in real time.
  • the sensing is independent of workpiece moving directions and is therefore omni-directional.
  • Fig. 2 summarises typical sensor response patterns to different weld faults in high speed (500mm/sec. traverse) laser butt welding. The signal is obtained by smoothing the acoustic nozzle signal using an RMS circuit. The patterns shown in Fig. 2 are idealized. The effect of operating parameters during laser welding is found to be:
  • Laser power variation effect at either too high power or too low power the acoustic nozzle signal reduces. There is an optimum power value so that the acoustic nozzle signal is at peak; at the same time the weld quality is optimum.
  • Traverse speed effect During, say, laser lap welding, it is required that the workpiece traverses relative to the laser beam. It has been found that there is a peak acoustic signal response at a certain speed. Above or below this speed the acoustic sensor signal reduces. The weld bead appearance at the peak acoustic sensor signal appears optimum for lap welding.
  • Shroud gas flowrate effect In laser welding, inert gas (He, Ar, N2) is projected through the nozzle to the work area for the purpose of shroud and prevention of the hot particles reaching the lens in the lens holder.
  • the sensor signal response seems to increase linearly with the gas flowrate at a low flowrate region of, say, less than 200 litre/min.
  • gas flowrate is too high the principal signal source changes are described in the following.
  • Laser cutting monitoring For laser cutting, high pressure, high flowrate gas is used and injected through the coaxial nozzle to the laser generated melt pool to both blow away the molten material and to assist thermal input by chemical reaction (when 02 is used) .
  • the acoustic signal in this case is overwhelmed by the gas impact on the object below the nozzle. This signal is therefore dependent on gas pressure, flowrate and the object distance. The nearer the distance of the object to the workpiece the stronger the signal for the sub-sonic gas flow speed.
  • the acoustic nozzle is used as a distance sensor, a proximity sensor and workpiece edge detector.
  • the sensor signal is found to be very sensitive to object distance variations, especially at edges or holes.
  • the sensor response can clearly indicate this by a signal rise. If the cut kerf is too wide, the sensor signal response drops lower than for the normal cut. If there is dross or irregular holes, sensor response also fluctuates.
  • a good cut produces a smooth sensor response at a specified value, dependent on gas flowrate and nozzle stand off to the workpiece.
  • Fig. 3 summarizes the sensor response pattern for different cut qualities.
  • One advantage of the present sensor unit for laser cutting applications is that the signal is relatively insensitive to the workpiece material type so that, once calibrated, it can be used with different materials without changing the calibration.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Laser Beam Processing (AREA)

Abstract

Appareil et procédé permettant de surveiller un traitement par faisceau laser d'un élément à usiner, comprenant un capteur acoustique (10) monté sur un ensemble (12) de support d'ajutage pour laser qui est thermiquement isolé de l'ajutage lui-même par un élément thermo-isolant (30). On place également entre le capteur (10) et l'élément à usiner (24) un autre élément thermo-isolant se présentant sous forme d'une plaque (32) comportant un trou (34) que traverse le faisceau laser (16).
PCT/GB1992/001555 1991-08-24 1992-08-24 Appareil et procede permettant de surveiller un traitement par faisceau laser WO1993003882A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9118316.0 1991-08-24
GB9118316A GB2259269A (en) 1991-08-24 1991-08-24 Apparatus and method for monitoring laser material processing

Publications (1)

Publication Number Publication Date
WO1993003882A1 true WO1993003882A1 (fr) 1993-03-04

Family

ID=10700501

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1992/001555 WO1993003882A1 (fr) 1991-08-24 1992-08-24 Appareil et procede permettant de surveiller un traitement par faisceau laser

Country Status (3)

Country Link
AU (1) AU2449192A (fr)
GB (1) GB2259269A (fr)
WO (1) WO1993003882A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112975075A (zh) * 2019-12-16 2021-06-18 奥迪股份公司 用于监控焊接过程的系统

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002505199A (ja) * 1998-03-02 2002-02-19 エルパトローニク アクチエンゲゼルシヤフト 溶接シームを検査するための方法および装置
AU2002354327A1 (en) * 2002-11-08 2004-06-07 El.En S.P.A. Lasere machining device with ultrasound systemfor controlling the distance between the laser head and theworkpiece
JP5448042B2 (ja) * 2009-03-24 2014-03-19 株式会社スギノマシン レーザー加工装置、レーザー加工装置の製造方法、及びレーザー加工方法
GB2511036B (en) * 2013-02-15 2015-12-16 Rolls Royce Plc Process and Apparatus for Cleaning a Surface

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0294324A1 (fr) * 1987-05-18 1988-12-07 C.A. Weidmüller GmbH & Co. Outil d'usinage au laser
JPH03165979A (ja) * 1989-11-27 1991-07-17 Amada Co Ltd レーザ加工装置

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4932846A (fr) * 1972-07-27 1974-03-26

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0294324A1 (fr) * 1987-05-18 1988-12-07 C.A. Weidmüller GmbH & Co. Outil d'usinage au laser
JPH03165979A (ja) * 1989-11-27 1991-07-17 Amada Co Ltd レーザ加工装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 15, no. 404 (M-1168)15 October 1991 & JP,A,3 165 979 ( AMADA CO. LTD ) 17 July 1991 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112975075A (zh) * 2019-12-16 2021-06-18 奥迪股份公司 用于监控焊接过程的系统

Also Published As

Publication number Publication date
AU2449192A (en) 1993-03-16
GB9118316D0 (en) 1991-10-09
GB2259269A (en) 1993-03-10

Similar Documents

Publication Publication Date Title
US5304774A (en) Method and apparatus for monitoring weld quality
US5674415A (en) Method and apparatus for real time weld monitoring
JP5459922B2 (ja) 材料加工プロセスのプロセス・パラメータを測定する方法および装置
Sun et al. Sensor systems for real-time monitoring of laser weld quality
US5486677A (en) Method of and apparatus for machining workpieces with a laser beam
US8410392B2 (en) Machining device and method for machining material
Shao et al. Review of techniques for on-line monitoring and inspection of laser welding
KR100420722B1 (ko) 소재상에서의가공을위한빔또는제트를모니터하고위치결정하기위한방법및장치
Miyamoto et al. Development of in-process monitoring system for laser welding
US4477712A (en) Arc-welding seam-tracking applications employing passive infrared sensors
WO1993003881A1 (fr) Appareil et procede permettant de surveiller un traitement par faisceau laser
WO1993003882A1 (fr) Appareil et procede permettant de surveiller un traitement par faisceau laser
JP2012071340A (ja) レーザ加工装置
Li et al. In-process clad quality monitoring using optical method
GB2300534A (en) Automatic focussing of industrial laser beam
Haran et al. Optical signal oscillations in laser keyhole welding and potential application to lap welding
JP3603829B2 (ja) レーザ溶接の品質検査方法
KR200164249Y1 (ko) 레이저 가공장치
US5013886A (en) Real-time magnetic-flux breakthrough detection method and system for laser drilling
Haran et al. Process-control in laser welding utilising optical signal oscillations
US20060108341A1 (en) Method and installation for pointing a fine fluid jet, in particular in welding, or laser hardfacing
Kogel-Hollacher et al. Process monitoring or process control in laser materials processing
US6504383B1 (en) Device for monitoring welds
GB2281393A (en) Gas acoustic distance measuring probe
JP3323874B2 (ja) レーザ加工装置

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AU CA FI JP NO US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
WA Withdrawal of international application
NENP Non-entry into the national phase

Ref country code: CA