BMW Group, 27.01.2015
LASER BEAM WELDING OF ALUMINIUM DOORS. Dipl.-Ing. Johannes Kellner Dr.-Ing. Florian Oefele
CONTENT. Evolution and motivation Challenges Door production BMW 5-series (F10) Advancements & Outlook
BMW - Laser beam welding of aluminium doors, 27.01.2015
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EVOLUTION OF LASER WELDED DOORS AT BMW.
?
BMW 1-series
BMW 7-series BMW 5-series
Aluminium laser door welding Tactile, Door structure 2008
BMW - Laser beam welding of aluminium doors, 27.01.2015
Aluminium laser door welding
Steel laser door welding Tactile, Outer-panel
2010
Mini
2012
Remote, doorstructure
2014
2016
2018 Page 3
ADVANTAGES OF LASERWELDED ALUMINIUM DOORS. Door weight -44%
Weight reduction steel
E60
aluminium
F10
Enhanced stiffness of door structure
Enhanced aeroacoustic Air frame noise reduction BMW - Laser beam welding of aluminium doors, 27.01.2015
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TACTILE LASER WELDING OF ALUMINIUM. PROCESS DESCRIPTION. Laser head is tactilely guided by filler wire Possibility to take influence on alloy composition by selection of filler wire High process stability Laser beam
Filler wire
Laser weld Upper sheet
Lower sheet BMW - Laser beam welding of aluminium doors, 27.01.2015
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CONTENT. Evolution and motivation Challenges Door production BMW 5-series (F10) Advancements & Outlook
BMW - Laser beam welding of aluminium doors, 27.01.2015
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REQUIREMENTS FOR LASER WELDS ON THE OUTER PANEL.
Hot cracks Pores Seam geometry Joining width
Pores Spatter Edge embedding Plate lamination Smoke
Optics Roughness of surface Regularity
BMW - Laser beam welding of aluminium doors, 27.01.2015
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REQUIREMENTS FOR ALUMINIUM WELDS. CONNECTION STRENGTH. Storage period Prevention of embrittlement Processing period in series production
Materials
Hot crack resistence
Construction
Filler wire
Part construction
Grain-refining elements High-alloyed weld additives
Edge distance Material thinning by forming
Base material Hot-crack resistent alloys (5xxx)
Measures Energy per unit length
Clamping situation Avoidment of tensile stress in the joint area
Thermal part stress Welding velocity Intensity distribution Heat conduction BMW - Laser beam welding of aluminium doors, 27.01.2015
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TACILE LASER WELDING. PROCESS MONITORING SYSTEM. Inline (Analyzing grey pictures) camera module
laser beam additional lightning Laser beam / wire position Laser weld OK
seam
failure
melt
BMW - Laser beam welding of aluminium doors, 27.01.2015
keyhole
Mismatch laser beam / wire position Laser weld on the upper sheet
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CONTENT. Evolution and motivation Challenges Door production BMW 5-series (F10) Advancements & Outlook
BMW - Laser beam welding of aluminium doors, 27.01.2015
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DOOR PRODUCTION 5-SERIES. WELDING SEQUENCE FRONT DOOR LEFT.
Station 1:
Station 2:
Closing plate and inner door panel Nr. of seams: 7 Seam length: 1058 mm
Closing plate and inner door panel Nr. of seams: 5 Seam length: 1360 mm
Total seams: 29 Total seam length: 3501 mm Total process time: ~110 sec Station 3:
Station 4:
Closing plate and inner door panel + window guide rail Nr. of seams: 10 Seam length: 570 mm
Closing plate and inner door panel + window guide rail Nr. of seams: 7 Seam length: 513 mm
BMW - Laser beam welding of aluminium doors, 27.01.2015
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DOOR PRODUCTION 5-SERIES. Restackin g station
Specifications Production site Net area
Dingolfing 4150 m²
Investment
26,4 million €
Technical design main production line (2 shifts)
850 u / day
Availability
90 %
Cycle time
53 sec.
Rear door right
Front door right
Central door delivery for ongoing oven process
Workers Assembler (door hinges)
8 present / shift
Tester
2 present / shift
Loader
3 present / shift
BMW - Laser beam welding of aluminium doors, 27.01.2015
Rear door left
Front door left Dryer Page 12
DOOR PRODUCTION 5-SERIES.
BMW - Laser beam welding of aluminium doors, 27.01.2015
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CONTENT. Evolution and motivation Challenges Door production BMW 5-series (F10) Advancements & Outlook
BMW - Laser beam welding of aluminium doors, 27.01.2015
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ADVANCEMENTS & OUTLOOK
Future Trends:
Enhancement of weld seam quality (visible seams on outer panel)
Increased welding velocity
BMW - Laser beam welding of aluminium doors, 27.01.2015
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REQUIREMENTS FOR LASER WELDS ON THE OUTER PANEL.
Hot cracks Pores Seam geometry Joining width
Pores Spatter Edge embedding Plate lamination Smoke
Optics Roughness of surface Regularity
BMW - Laser beam welding of aluminium doors, 27.01.2015
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REQUIREMENTS FOR LASER WELDS ON THE OUTER PANEL. Corrosion prevention: Increased requirements regarding corrosion prevention for outer panel welds Pores and cracks can lead to unsufficient edp-coating an underfilm corrosion
Lacking edge embedding Cracks Spatters
Lubricant
Pores
Capillary Melt pool with spatters Solidified melt pool lubricant
Capillary BMW - Laser beam welding of aluminium doors, 27.01.2015
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QUALITY INSPECTION SYSTEM
Laser triangulation (W+R-System) Function: Generates a 3D-Image of the laser weld by laser triangulation Defects are detected and visualized
Robot flange Image sensor Camera optics
onscreen for worker
Detection:
Laser beam
Pores > 0,3 mm Spatter > 0,3 mm Lack of edge embedding
BMW - Laser beam welding of aluminium doors, 27.01.2015
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QUALITY INSPECTION SYSTEM.
Laser triangulation (W+R-System) Light-Section (Development with Automation W&R) Pores
Spatter
Detection of 3 values / picture Robust against process disturbances Edge Embedding
BMW - Laser beam welding of aluminium doors, 27.01.2015
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SUMMARY AND OUTLOOK Reduction of CO2 emissions demands light materials as aluminium. Aluminium laser welding of doors is state of the art at BMW since 2008. Quality of aluminium laser welds improved in the past years. Outer panel welds are now realizable . Increasing use of laser technology in body-in-white production at BMW. Further developments for process monitoring and quality inspection systems are available. New welding concepts for aluminium and other BMW - Laser beam welding of aluminium doors, 27.01.2015
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