激光焊接PRECITEC_QUALITY CONTROL IN WELDING PROCESS.ppt

1、Process Monitoring forLaser Welding Systems,General presentation with focus on in process“ monitoring.,Requirements on process monitoring Seam quality Process monitoring systems Precitec Group,Requirements on process monitoring Seam quality Process monitoring systems Precitec Group,Requirements on p

2、rocess monitoring,Quality assurance in mass production,Cost efficiency,zero failure tolerance,Traceability of bad welds,100%- Documentation,Requirements on process monitoring,Man Machine Interface (MMI),simple graphical user interface (GUI),integration in QM system,easy maintanance,remote service /

3、via Internet,simple integration to the laser machine,Requirements on process monitoring Seam quality Influences Characteristics Process monitoring systems Precitec Group,Laser Welding Principle,Conduction welding The specimen gets heated up to welding temperature. The penetration depth is limited by

4、 heat conduction Deep penetration welding Beyond threshold intensity, a vapour capillary (Keyhole) is formed, which deeply penetrates the specimen. The laser beam led withing this capillary . The melt pool is formed by the capillary which moves through the specimen. When talking about laser welding

5、usually deep penetration welding is meant.,Influences on the weld quality,Process phases,Handling / Clamping: + position of the workpiece + alignment of workpieces to each other + feed rate,Weld quality,Influences on the weld quality : Pre-Process,Workpiece: + material properties + joint geometrie +

6、 dirt,Weld quality,Laser Source: + beam quality + laser power,Process components + filler wire + shielding gas,Handling / Clamping: + focal position + seam position + shape distortion (heat) + feed rate,Influences on the weld quality : In-Process,Workpiece: + material properties + joint geometrie +

7、dirt,Weld quality,Workpiece: + cracks,Handling / Clamping: + distortion vs. tension,Influences on the weld quality : Post-Process,Monitoring (Control) of Quality Relevant Characteristics,Pre-Process:,cross section of connection,welding depth / root fusion,dropouts,seam position,Post-Process:,In-Proc

8、ess:,holes,holes / pinholes (open pores),cracks,position of joint partners / gap,position TCP / seam,insufficient fill,undercut notches,face/root reinforcement,spatter,Requirements on process monitoring Seam quality Process monitoring systems Survey In-Process monitoring sample Precitec Group,Pre-Pr

9、ocess Closed Loop Control: Seam Tracking,Laser Path Finder,Based on triangulation,Accuracy: 0.05mm,Teach-In track in the TCP enables compensation of characteristic machine / robot vibrations,LPF Set Up for Roof Welding at BMW,welding direction,clamping wheel,CMOS camera,nozzle YW50,Pre-Process Contr

10、ol,Pre-Process Control seam tracking seam geometry,In-Process Control temperature plasma back reflection melt pool geometry,Post-Process Control seam geometry,Laser Process,Process Monitoring and Control,In Process Monitoring - Signals,Process radiation,Laser Process,In-Process-Monitoring Temperatur

11、e Plasma ( or metal plume ) Back reflection (Nd:YAG) Laser power (Nd:YAG) Melt pool geometry,Survey In-Process : Sensory Devices YAG-LASER,Welding Head with integrated sensors Plasma Temperature Laser back reflexion Laser power Camera (teach in) Seam Tracking (with closed loop controled axes ) Cover

12、 slide monitoring Crossjet Outlet for shielding gas (internal guidance),Integration of internal sensors to the beam path,Sensors can be integrated within the beam source in a similar way,Welding head with integrated sensors (YW50),integrated sensor module Plasma Temperature Laser back reflexion Lase

13、r power,Linear drives (Y,Z) for seam tracking Seam tracking camera Cross-Jet Coaxial shielding gas supply,Survey In-Prozess : Sensors for CO2-LASER,External sensors Plasma Temperature P,T combined Camera Sensors can be adjusted to certain areas of the melt pool and welding area,Internal sensors - Sc

14、raper sensor - combined Plasma Temperature Integration within beam path: protected against pollution no interference with workpiece,Survey In-Prozess,Aquisition of process emission (CO2),Photodiodes: + Temperature + Plasma,LWM-Scraper,MPM-Camera,Survey In-Prozess,Realtime processing Marking of failu

15、res during welding process,Data aquisition,CO2,Nd:YAG,3. Automatic monitoring,1. Setup software,2. References,Signal processing & visualisation,Laser Welding Monitor LWM-C,Properties,Windows based real time processing with DSP high sample rate: 20 kHz can handle up to 8 signals at the same time diod

16、e and camera based signals can be processed SQL-database TCP/IP connection remote control via Internet,Timesharing,Timesharing with several welding heads connected to one laser (aim: Laser-On-Time = 100%) alternate processing of up to: 8x2 Sensors (e.g. Scraper or int.YAG: Temp. and Plasma) or 4x4 S

17、ensors (e.g. YW50: Temp, Plasma, Laser back reflexion, Laser power),Laser - network,Laser source,Laser source,Beamswitch,Sensors: Laser power Plasma Laser back reflexion Temperature,Sensors: Laser power Plasma Laser back reflexion Temperature,Sensors: Laser power Plasma Laser back reflexion Temperature,Sensoren: Laser power Plasma Laser back reflexion Temperature,Process visualisation,Working principle of LWM,Laser Welding Monitor LWM Neuvorstellung SGM,left : Teil IO,right : Teil NIO, 0,25 mm lateral offset,Plasma signal