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Seam-tracked Laser Beam Remote Welding
with Automated Gap Bridging
Dr.-Ing. Florian Albert
Scansonic MI GmbHApplication CenterBerlin, Germany
INDUSTRIAL LASER APPLICATIONS Munich, 24.06.2015
Outline
1. Company profile
2. Initial situation and challenges for laser remote welding
3. Solution RLW-A
a) Seam tracking
b) Bridging gaps
4. Conclusion and Acknowledgement
Scansonic MI GmbH Seam Tracked Laser Remote Welding with Automated Gap Bridging
1 Company Profile – SCANSONIC
� Founding of the company: 2000
� Market leader in seam tracked laser brazing/welding at bodywork
� Prime market: automotive industry and suppliers for automotive engineering
� Number of employees: app. 200 (permanent staff) + 20 (interns/students)
� 2015: > 2.000 laser optics in use worldwide
� DIN EN ISO 9001 certified
� Own application center with 5 lasers (diode and disk lasers up to 8 kW) and 8 robots
Scansonic MI GmbH Seam Tracked Laser Remote Welding with Automated Gap Bridging
1 Company Profile – Scansonic Optics in Europe
Audi, VWBratislava
PSARennes
Magna SteyrAlbersdorf
Seat, AudiMartorell
SkodaKvasiny
NTO IRE-PolusMoskwa
RenaultNovo Mesto
VolvoOlofström
FiatTurin
Deutschland: Audi, Bombardier, BMW, Daimler, KWD, MTU, Opel, Photon, Porsche, Viessmann, VW
BMW MiniOxford
VolvoUmeå
PSASochaux
PSAPoissy
PSAMulhouse
AudiBrüssel
RenaultDouai
PSATrnava
AudiGyőr
VWPoznań
SkodaMladá Boleslav
Laser CenterSankt Petersburg
GAZNischni Nowgorod
DaimlerKecskemét
BMW MiniSwindon
DaimlerVitoria
VW AutoeuropaPalmela
PSAMadrid
PSAVigo
GMEllesmere Port
GMLuton
VWPamplona
voestalpine Polynorm B.V.Bunschoten
Valmet Automotive Inc.Uusikaupunki
Scansonic MI GmbH Seam Tracked Laser Remote Welding with Automated Gap Bridging
2 Initial Situation
� Laser Remote Welding is gaining more and more attention (e.g. in BIW production)
� No wire costs
� Short cycle time because of a reduced auxiliary process time
� But: component tolerances are a major challenge for the usage of remote welding
� Difference between programmed beam position and the actual componentlocation must be compensated bycomplex and thus costly design measures
� A changing gap situation makes itdifficult to choose suitable processparameters to reach a bridged weldseam
Door Audi A8 *)
welding withScansonic ALO3
*) Latzl., M.: Die leichte und funktionale Tür des neuen Audi A8. In: Proceedings of Türen und Klappen, 2010
Scansonic MI GmbH Seam Tracked Laser Remote Welding with Automated Gap Bridging
2 Challenges
Scansonic MI GmbH Seam Tracked Laser Remote Welding with Automated Gap Bridging
� Laser Remote Welding of fillet or sq. butt welds
� with seam tracking
� with gap bridging
Stampingfailures(simulated)
� Challenge:Following the edge
Stampingfailures(simulated)
� Challenge:Following the edge
Gap between the sheets
� Challenge:Bridging the gap withoutfiller wire
Gap between the sheets
� Challenge:Bridging the gap withoutfiller wire
� Remote Welding Optic RLW-A
Welding with Scansonic RLW-A
+ No wire costs
+ High efficiency
- How to find theseam?
- How to bridgegaps?
new optic for high precision Remote-Welding with opticalseam tracking and beam oscillation
Scansonic MI GmbH
3 Solution RLW-A
Seam Tracked Laser Remote Welding with Automated Gap Bridging
3a Seam Tracking
Scansonic MI GmbH Seam Tracked Laser Remote Welding with Automated Gap Bridging
� Forerun 10 mm
� System gets time to react
� Robot program strategy must be considered (Fixture, Shadows, Orientation), like tactile head
� Advantages of 3 linens (6D):
� Cartesian and angular positions are known (how is the head positioned in reference to the part)
� More redundancy and stable seam recognition (more measurement data)
� Important:
� Seam tacking lines cover complete y scan range (±16.5 mm)
� Seam tracking lines are fixed in position
� But special On-The-Fly function still possible (moving x-scanner)
x
laserspot
seam-trackinglines
Process direction
y
y travelrange
for run
3a Seam Tracking
Scansonic MI GmbH Seam Tracked Laser Remote Welding with Automated Gap Bridging
Deliberately caused edge faults (cutting tool):
RLW
Lower Sheet
Upper Sheet
RLW
Gap
Melt Pool
Oxide Skin
RLW
Initial Situation
� Gap beetween upper and lower sheet can not be bridged with standard parameter for zero gap situation
� Adjustments of process parameters are necessary
Problem
� Oxide skin around the melt pool leads to high surface tension and joining failures
� Increasing of melt pool by using bigger beam diameters is not sufficient due to loss of beam intensity � instable keyhole
Solution
� Increasing the melt pool by beam oscillation � high beam intensity + large melt pool
� High beam velocity leads to a good material deposition from upper to lower sheet
Bridged Gap
3b Bridging Gaps
Scansonic MI GmbH Seam Tracked Laser Remote Welding with Automated Gap Bridging
Oscillationin y or x&y
upper sheet
lower sheet
� By seam tracking the correct position of the laser beam and the gap between the sheets are known
� A geometrical model and the necessary S-Value give information about:
� Y-Offset of the beam
� Amplitude of beam oscillation
� Laser power
� (Frequency of beam oscillation)S-Value = 0.7 x t
Scansonic MI GmbH
3b Bridging Gaps
Seam Tracked Laser Remote Welding with Automated Gap Bridging
3b Bridging Gaps
Gap: 0 mm
Gap: 0.7 – 0.8 mm
� Automated seam tracking in Y
� Bridging of a varying gap by an adjustment of laser power, beam offset and oscillation amplitude in Y
� Bridging of a hs = 0 … 0.8 mm gap at two t = 0.8 mm zinc coated steel sheets
� S-Value at every position > 0.7 x t
Scansonic MI GmbH Seam Tracked Laser Remote Welding with Automated Gap Bridging
Gap height
to 0.05mm 0.05 mm –0.2 mm
0.2 mm –0.4 mm
0.4 mm –0.6 mm
0.6 mm –0.7 mm
Oscillationstrategy
Non-oscillated Transversal (Y)
Transversal (Y)
Transversal (Y)
Transversal (Y)
Front andback sideof steelsheets
Cross sectionview
[VS 2.5m/min;H260LAD]
Reproducible, proper welds
3b Bridging Gaps
Scansonic MI GmbH Seam Tracked Laser Remote Welding with Automated Gap Bridging
Beam Oscillation in Y-Direction
Gap 0mmGap 0,6 mm Gap 0 mm
No full penetration, uniform heating
Backside
3b Bridging Gaps
Seam Tracked Laser Remote Welding with Automated Gap BridgingScansonic MI GmbH
Material: AW 6082; t=1,5
Gap 0,5 mm
Micro Sections
Material: AW 5182; t=1,5Gap 0 mm
1,5 mm
0,4 mm
0,5 mm
Beam Oscillation in Y-Direction
3b Bridging Gaps
Seam Tracked Laser Remote Welding with Automated Gap BridgingScansonic MI GmbH
� At remote welding seam tracking is necessary to realize fillet welds or butt welds at the correct position
� At remote welding gap bridging is possible by a controlled change of parameter
� The measurement of the gap allows to control the process parameter(laser power, beam offset, amplitude and frequency of oscillation)
� The necessary S-value leads to correct parameter based on a developed model
Thank you for your attention!
The author would like to thank the German Federal Ministry of Education and Research(BMBF) for the support of parts of the carried out work within the “Brightlas ResearchProject”.
Conclusion and Acknowledgement
Scansonic MI GmbH concl.Seam Tracked Laser Remote Welding with Automated Gap Bridging