The comparison of automotive assembly method between spot welding & laser welding in term of application and cost

1. BODY ASSEMBLY PROCESS
LASERWELDINGVS SPOTWELDING

2. AUTOMOTIVE LASER WELDING
LASER WELDING COMPARISON
Process
Type
Laser Type Application Area Advantages Disadvantages Remarks
Single Sided
Process
• CO2
- High Power (6
kW)
• Nd:YAG
- Low Power (4
kW)
• Butt / Edge joint
(brazing applications)
• Lap joint
• TWB – Door inner
panels
• Roof to side structure
• Sub assembly process
• Closure hemming
flange
• Good weld
accessibility (Single
Side
Process)
• Reduced width of -
or elimination of -
the flange, resulting
in reduced vehicle
weight.
• Low operational cost
• Panel gap constraint
(no clamping force)
• Narrow penetration
(nugget)
• Tighter parts &
assembly tolerance
• Worse corrosion risk
vs
spot welding
• High price
• Jig / fixtures
needed for
panels
clamping / support
to eliminate panel
gap
• Suitable as
MIG welding (eg
CO2) alternatives
Double Sided
Process
• Laser Seam
Stepper (LSS)
- Low Power (2
kW)
• Lap joint • Respot process • Higher process
speed (shorter cycle
times)
• Increased component
strength by longer
seams with higher
torsional stiffness
• ‘Build in’ clamping
force function
(eliminate panel gap)
• Low operation cost
• Weld point
accessibility same as
spot welding gun
• Suitable as spot
welding
alternatives

3. AUTOMOTIVE LASER WELDING
COST COMPARISON
Estimated
Cost
Resistance Spot Welding
GMAW (Mix
Ag/CO2) Welding
Laser Welding
Remarks
Single Sided
Process
Double Sided
Process
Welding
Equipment
per set
RM 50k to 70k RM 60k to 70k RM 450k ???
•Waiting
estimation
from vendor
Cost per Spot
Servo / Trans
Gun – 70kW
Total : RM
0.0115 Total : RM 0.016
/ 10mm length
Total : RM 0.008 /
25mm length
Total : RM 0.012 /
30mm length
*Equivalent to 3 spot
weldingPneumatic
Gun – 150kW
Total : RM 0.048
Resistance Spot
Welding
GMAW (Mix
Ag/CO2) Welding
Laser Welding
Remarks
Single Sided
Process
Double Sided Process
1 spot (general)
= 4√tmin (Ø) 10mm (length)
18 ~ 25mm (length)
*Straight pattern
30mm / LSS
*Equivalent to 3 spot
welding
* Zig-zag pattern
• Reference :
i. Single Sided Process : Volvo
practice
ii. Double Sided Process :
Photonics.com
WELDING EQUIVALENT APPROXIMATION
*Note : Please refer to calculation table on “Reference” section

4. REFERENCES
LASERWELDINGVS SPOTWELDING

5. AUTOMOTIVE LASER WELDING
LASER SEAM STEPPER (LSS)
FIGURE 1. Laser-Seam-Stepper (left without C-Gun; right with C-Gun)
FIGURE 2. Resistance spot welding vs. laser
welding with COSY LSS1-C-Gun
1 laser weld
seam = 2~3
spot points
Laser welding for the production of sheet metal components in body
plants offers the following advantages:
• Higher process speed (shorter cycle times)
• Increased component strength by longer seams with higher torsional
stiffness
• Efforts and costs comparable to today’s modern resistance welding systems
• Realization of high job safety requirements with reduced costs

6. AUTOMOTIVE LASER WELDING
Nd : YAG LASER WELDING
Figure 1:Standard Operation
Figure 2:Schematic Diagram
Laser welding advantages:
• Narrow weld profile
• Consistent weld bead
• No electrode wear (Non-contact process)
• High spot accessibility (1 sided process)
• No filler material

7. AUTOMOTIVE LASER WELDING
GENERAL GUIDANCE
CO2
Laser
Nd : YAG
Laser

8. AUTOMOTIVE LASER WELDING
REFERENCE FROM VOLVO
Email

9. AUTOMOTIVE LASER WELDING
COSTING CALCULATION
Day Night Average
0.355 0.219 0.287
Elements
Vin (V) Iin (A) Powerin (kVA) Weld Time (Cycle) Energyin (kWh)
415 170 70.55 15 0.005879167 0.001687321
Powerin (kW) Moving time / Spot (sec) Energyin (kWh)
7.2 5 0.01
RM / hour
78.88
RM / Tip Spot / Tip
2.4 6000
0.011530654
Powerin (kVA) Weld Time (Cycle) Energyin (kWh) Cost / Spot (RM)
150 15 0.0125 0.0035875
Daily Production Working Day Spot / Man Salary / Man
100 20 20 1500
RM / hour
78.88
RM / Tip Spot / Tip
2.4 6000
Forceweld (kN) Velocityelectrode (m/sec) Powerin (kW) Squeeze Time (cycle) Hold Time (cycle) Energyin (kWh)
2.45 0.2 2.23 20 5 0.000494949
0.048202884
Vin (V) Iin (A) Powerin (kVA) Weld Speed (m/sec) Weld Length (m) Weld Time (sec) Cost / length (RM)
15 95 1.425 0.005 0.01 2 0.000227208
Powerin (kW) Moving time / Spot (sec) Energyin (kWh)
6 5 0.011666667
Car / roll RM / Roll Length (mm/car) RM/mm RM/10mm
1000 86 250 0.000344 0.00344
Car / roll RM / Cylinder RM / Car RM/10mm
500 118 0.236 0.00944
0.016455542
Powerin (kW) Weld Speed (m/sec) Weld Length (m) Weld Time (sec) Cost / length (RM)
4 0.083 0.025 0.301204819 0.00009605
Powerin (kW) Moving time / Spot (sec) Energyin (kWh)
6 5 0.008835341
0.008931392
Powerin (kW) Weld Time (sec) Cost / length (RM)
2 2 0.00031889
Powerin (kW) Moving time / Spot (sec) Energyin (kWh)
6 5 0.011666667
0.011985556Total
LaserWelding
- 0.011666667
7.5
- - - - - -
DoubleSidedProcess
Weld Setting - -
Robot Power
Apparent Power (kVA)
- 0
Total
- -
SingleSidedProcess
- - - - -
Weld Setting
Robot Power
Apparent Power (kVA)
- 0.008835341
7.5
GMAW(MixAg/CO2)
- -
Total
0.003348333
0.00344
0.00944
0
CO2 Gas - -
- - - -
CO2 Wire -
Weld Setting
Robot Power
Apparent Power (kVA)
-
7.5
-
Total
ResistanceSpotWelding
Electrical Tariff, RM / kWh
Parameters
- - -
- - -
-
-
-
-
Total
- -
-
- -
-
-
-
-
0.0004
Pneumatic / Air
0.000142051
- - - -
- - -
Servo/TransGunPneumaticGun
Welding Transformer
Manpower 0.0375
Water Pump 0.006573333
Electrode Tip
Water Pump 0.006573333
Electrode Tip 0.0004
0- - - -
Welding Transformer
Robot Power
Apparent Power (kVA)
9
0.00287
Cost / Spot (RM)