Presented at Great Designs in Steel - Autosteel/media/Files/Autosteel/Great Designs in Steel... ·...

The Real Cost of Laser Welding

Presented at Great Designs in Steel

Stan Ream, Laser Technology Leader

Jim Tighe, CFO

EWI

Outline • How do you measure cost?

• How does your boss measure cost?

• The “ABCs” of laser welding costs.

• Blank welding study cases

• How important is the laser in the laser system?

• Other factors that influence welding cost.

How to you measure cost? - or how are you graded? -

• Cost of the laser

• Cost of the motion system

• Cost of associated automation

• Operating consumables

• Number of staff on the line

• How do Controllers look at cost? – Sunk Cost

• “Can’t we continue using what we have?”

– Cash Outlay • “What’s this going to cost?”

– ROI / Break-Even • “When are we going to be ahead?”

• We need to speak a common language to come to the right answer – The “ABCs” (activity based costing) – Meaningful discussions on making investments

Process Elements

Operational Cost Summary

Cost Elements

Accountant Speak

Production Speak

Process Elements Operational

Cost Summary Cost

Elements

Direct Variable

Consumables

Capital

Equipment

Other Costs

Tooling

Payroll

Employees

Overhead

Sunk Costs

Acc

ou

nta

nt

Spea

k

Pro

du

ctio

n S

pea

k

Process Time, Load/Unload Time, Maintenance Cycles, Useful Life

Allocated Floor Space

Custom Fixturing, Useful Life

Air, Gas, Electricity…

Staffing Quantity and Level, Shift Routines

Co

st /

Pro

du

ctiv

ity

“Fully Burdened Cost per

Part”

“Cost of a Part”

Much to Consider - don’t even try to read this now -

Welding Process Cost Calculator: User Input - Variable with Process

User Input - Infrequent

Calculated Output - Metrics

Calculated Output - Cost

Need to "fix" to become part of the model

Cost Elements Input Units Operation Elements Operational Cost Summary Output Units

Compressed Air -$ $/100cf standby compressed air usage - cfh

process compressed air usage - cfh

Helium Gas (laser) 34.36$ $/100cf laser helium gas usage 1.70 cfh Consumable Cost (laser and process gas) 41.84 $/hr

helium plasma assist gas usage (60 cfh x 2) 120.00 cfh

Nitrogen Gas (laser) 3.95$ $/100cf laser nitrogen gas usage 0.35 cfh

CO2 Gas (laser) 3.90$ $/100cf laser CO2 usage 0.07 cfh

Argon Shielding Gas 6.54$ $/100cf welding trailing shield gas usage - cfh

Other Gas -$ $/100cf

Wire -$ $/lb. filler wire diameter - inch

filler wire speed - inch/min

Electric Power 0.0600$ $/(kw-hr) Runtime electric power 120 kw Runtime Electric Power 6.34$

Standby electric power 50 kw Standby Electric Power 0.36$

Total Electric Cost 6.70$ $/hr

PROCESS EQUIPMENT - 6kW CO2 Laser 400,000$ $ process equipment space 5,000 ft.2 Avg. PROCESS EQUIP. - Depreciation 7.81 $/hr

PROCESS EQUIPMENT - Salvage Value % 10 % load time 0 sec Avg. FIXTURING EQUIP. - Depreciation 0.00 $/hr

Avg. PART HANDLING EQUIP. - Depreciation 68.35 $/hr

FIXTURING EQUIP. - ___ -$ $ Travel speed 260 in/min 6.5 m/min Average Total Equipment Depreciation 76.16 $/hr

FIXTURING EQUIP. - Salvage Value % 10 % Weld length 60.00 inch/weld 1.5 m Average Interest on Equipment 12.58 $/hr

number of welds per part 1 welds/part Average Depreciation & Interest (8 years) 88.74 $/hr

PART HANDLING EQUIP. - 2 Station Clamp Line 3,500,000$ $ indexing time per part - sec/part Asset Value at End of 8 Years $390,440

PART HANDLING EQUIP. - Salvage Value % 10 % unload time - sec

1st YR PROCESS EQUIP. - Depreciation 17.36 $/hr

1st YR FIXTURING EQUIP. - Depreciation 0.00 $/hr

1st YR PART HANDLING EQUIP. - Depreciation 151.91 $/hr

Total Equipment Depreciation 169.27 $/hr

First Year Equipment Interest 25.39 $/hr

First Year Depreciation & Interest 194.66 $/hr

Cycle Time 13.85 seconds/part

Output Coupler 2,000$ $/ea. Output Coupler life 1,000 hours

Cooling Water Filters 1,000$ $/ea. Cooling Water Filters life 1,000 hours

Blower 5,000$ $/ea. Blower life 4.00 yr

Focus Optics, 2 sets 6,000$ $/set Focusing Optics Life 1,000 hours/set Long Term Parts Costs 15.52 $/hr

Beam Delivery Optics 10,000$ $/set Beam Delivery Optics Life 10,000 hours/set

Beam Trap 1,000$ $/ea. Beam Trap 500 hours

Clamp feet 1,000$ $/ea. Clamp feet 3,000 hours

Belts 1,000$ $/ea. Belts 1.50 yr

Laser RF Tube 22,000$ $/item RF tube life 1.60 yr

Laser Vacuum Pump 2,500$ $/item Vacuum Pump life 2.50 yr

Operator Burdened Wage ( req'd) 20.75$ $/hr Operator Loading 2 operators/line

Handler Burdened Wage 17.70$ $/hr Handler Loading 4 lines/handler

Supervisor Burdened Wage 38.00$ $/hr Supervisor Loading 6 lines/supervisor

Maintenance Burdened Wage 28.00$ $/hr Maintenance Loading 6 lines/maint tech Direct Labor Cost 56.93 $/hr

Tool Maker Burdened Wage (indirect) 34.00$ $/hr Tool Maker Loading (indirect) 12 lines/tool maker

Engineering Support Staff burdened wage (indirect) 60.00$ $/hr Engineering Staff Loading, including QA 6 lines/engr. Indirect Labor 12.83 $/hr

Maintenance Functions

Laser Tuning 2.00 hrs/month

Focus Optics Cleaning 12.00 hrs/month

Beam Path Alignment 6.00 hrs/month

Other Maintenance 16.00 hrs/month

Total scheduled maintenance 36.00 hrs/month

Unscheduled maintenance 16.00 hrs/month

Total Maintenance 52.00 hrs/month Process Utilization 88% % of possible

meals & breaks 0.73 hrs/shift

Plant Space Cost with Utilities 45.00$ $/ft.2/yr facility schedule 3 shifts/day Plant Availability 720 shifts/yr

yearly schedule 240 days/yr Plant Availability 5,760 hours/yr

Cost of Money 5 %/yr Process Availability 5,232 hours/yr

Direct Facility Cost 39.06 $/hr

New

Equ

ipm

ent

O/H

Long

-Ter

m P

arts

Dir

ect V

aria

ble

Pay

roll

Blank Welding Cost Theme - already a very well known laser welding application -

shock absorber A-Pillar

B-Pillar roof reinforcement

lift gate inner

wheel house

side ring

rear door inner

front door inner floor pan front rail

engine rail

wheel house

bumper

The Example Welding System - circa 1995, courtesy TWB -

Base Case System Features

• 2 Machine Operators

• 2 Moving Clamps

• 6kW CO2 Laser

• Mechanical Beam Switch

• Semi-Robotic Loading

• Full Robotic Unloading

• Operator Beam Alignment

Laser Blank Welding Process Notes • Quality and Productivity Are Driven by:

– Edge Preparation

– Fit-up

– Process Alignment

Concavity Mismatch

Ideal

Many Things Can Go Wrong

Mismatch Mismatch

Concavity

Lack of Penetration

Convexity

Lack of Fusion

Steady Trend to Thinner Gauge - greater process precision required -

0.8 mm to 1.9 mm 0.7 mm to 1.2 mm

1996 2013

Cautionary Cost Comments! • Consumable costs used in the following cases

are not absolute or necessarily current.

• Equipment costs are amalgams of past and current information, not highly accurate.

• Welding speeds are conservatively stated.

• Calculated cost comparisons are believed to be directionally accurate but not absolute.

• Please don’t sue us!

Baseline System Cost - for analysis only…not current or actual -

• 6kW CO2 laser: $500,000

– Includes portion of plant-wide chiller system

– Includes beam delivery to both stations

• 2 Station Clamp Line: $3,500,000

– Includes robots

– Includes conveyors

– Includes de-stacking pallets

Baseline System Consumables

• Electricity – Laser – Chiller – Machine

• Gas – Laser: helium, nitrogen, CO2 – Welding process: helium, argon, CO2 – Beam path: nitrogen or clean, dry air

Replacement Components - short and long term…examples only -

• Laser – Output coupler and/or output window (3-6 mo.) – Cooling water filters (3-6 mo.) – Blower (3-6 yr)

• Beam delivery – Final focusing mirror (3-6 mo) – Beam path mirrors (2-5 yr)

• Clamp line – Beam trap (1-3 mo.) – Clamp feet (9-12 mo.) – Belts (1-2 yr.)

Baseline Optics Maintenance Time - example for analysis only -

• Laser – Resonator tuning (2 hr/mo) – Output coupler/window cleaning (2 hr/mo.)

• Beam path – Mirror cleaning (2 hr/mo.) – Mirror alignment (2 hr/mo.) – Focus mirror cleaning (15 min/day)

The Cost of Floor Space

• Portion of building depreciation

• Lighting

• HVAC

• Maintenance

• Expressed as $/ft2/yr

Cycle Time Elements* - one of two stations @ 6 m/min weld speed- 1. Pick & Place Part A 2. Index Part A Into Fixture 3. Clamp Part A 4. Pick & Place Part B 5. Stage Part B to Part A 6. Clamp Part B 7. Cycle Start 8. Weld Head Move into Position 9. Weld (part length / travel speed) 10. Cycle Stop 11. Unclamp Fixture 12. Switch Beam to Station 2 13. Lift Welded Part & Exit 14. Retract Fixture

Single Station Cycle Time = 36 seconds

Beam-On Percentage = 42% * Example Values Only

• Same parts & operating sequence

• 2 Operators

• No down-time included

Cycle Time Elements* - both stations @ 6 m/min weld speed-

Dual Station Cycle Time = 19 seconds Beam-On Percentage = 79%

* Example Values Only

Some of the Inputs to the Base Cast Cost Elements Input Units Operation Elements

Compressed Air -$ $/100cf standby compressed air usage - cfh

process compressed air usage - cfh

Helium Gas (laser) 34.36$ $/100cf laser helium gas usage 0.80 cfh

helium plasma assist gas flow per station 60.00 cfh

Nitrogen Gas (laser) 3.95$ $/100cf laser nitrogen gas usage 0.20 cfh

CO2 Gas (laser) 3.90$ $/100cf laser CO2 usage 0.04 cfh

Argon Shielding Gas 6.54$ $/100cf welding trailing shield gas usage - cfh

Other Gas -$ $/100cf

Wire -$ $/lb. filler wire diameter - inch

filler wire speed - inch/min

Electric Power 0.0600$ $/(kw-hr) Runtime electric power 120 kw

Standby electric power 50 kw

PROCESS EQUIPMENT - 6kW CO2 Laser 500,000$ $ process equipment space 5,000 ft.2

PROCESS EQUIPMENT - Salvage Value % 10 % Cycle Start gas flow 1 sec

FIXTURING EQUIP. - ___ -$ $ Travel speed 240 in/min 6

FIXTURING EQUIP. - Salvage Value % 10 % Weld length 60.00 inch/weld 1.5 m

number of welds per part 1 welds/part

PART HANDLING EQUIP. - 2 Station Clamp Line 3,500,000$ $ Beam Switch time per part 2 sec/part

PART HANDLING EQUIP. - Salvage Value % 10 % unload time 0.5 sec

Beam-on Time Per Part 15.0 sec

New

Eq

uip

men

tD

irect

Vari

ab

le

More Inputs to the Base Case Output Coupler 2,000$ $/ea. Output Coupler life 1,000 hours

Cooling Water Filters 1,000$ $/ea. Cooling Water Filters life 1,000 hours

Blower 5,000$ $/ea. Blower life 4.00 yr

Focus Optics, 2 sets 6,000$ $/set Focusing Optics Life 1,000 hours/set

Beam Delivery Optics 10,000$ $/set Beam Delivery Optics Life 10,000 hours/set

Beam Trap 1,000$ $/ea. Beam Trap 500 hours

Clamp feet 1,000$ $/ea. Clamp feet 3,000 hours

Belts 1,000$ $/ea. Belts 1.50 yr

Laser RF Tube 22,000$ $/item RF tube life 2.00 yr

Laser Vacuum Pump 2,500$ $/item Vacuum Pump life 2.50 yr

Operator Burdened Wage ( req'd) 20.75$ $/hr Operator Loading 2 operators/line

Handler Burdened Wage 17.70$ $/hr Handler Loading 4 lines/handler

Supervisor Burdened Wage 38.00$ $/hr Supervisor Loading 6 lines/supervisor

Maintenance Burdened Wage 28.00$ $/hr Maintenance Loading 6 lines/maint tech

Tool Maker Burdened Wage (indirect) 34.00$ $/hr Tool Maker Loading (indirect) 12 lines/tool maker

Engineering Support Staff burdened wage (indirect) 60.00$ $/hr Engineering Staff Loading, including QA 6 lines/engr.

Maintenance Functions

Laser Tuning 2.00 hrs/month

Focus Optics Cleaning 12.00 hrs/month

Beam Path Alignment 6.00 hrs/month

Other Maintenance 16.00 hrs/month

Total scheduled maintenance 36.00 hrs/month

Unscheduled maintenance 16.00 hrs/month

Total Maintenance 52.00 hrs/month

meals & breaks 0.73 hrs/shift

Plant Space Cost with Utilities 45.00$ $/ft.2/yr facility schedule 3 shifts/day

yearly schedule 240 days/yr

Cost of Money 5 %/yrO/H

Lo

ng

-Term

Par

tsP

ayro

ll

Base Case Outputs

Operational Cost Summary Output Units

Consumable Cost (laser and process gas) 15.01 $/hr

Runtime Electric Power 6.34$

Standby Electric Power 0.36$

Total Electric Cost 6.70$ $/hr

Avg. PROCESS EQUIP. - Depreciation 9.76 $/hr

Avg. FIXTURING EQUIP. - Depreciation 0.00 $/hr

Clamp Line & Material Handling 68.35 $/hr

Average Total Equipment Depreciation 78.12 $/hr

Average Interest on Equipment 12.90 $/hr

Average Depreciation & Interest (8 years) 91.01 $/hr

Asset Value at End of 8 Years $400,452

1st YR PROCESS EQUIP. - Depreciation 21.70 $/hr

1st YR FIXTURING EQUIP. - Depreciation 0.00 $/hr

1st YR PART HANDLING EQUIP. - Depreciation 151.91 $/hr

Total Equipment Depreciation 173.61 $/hr

First Year Equipment Interest 26.04 $/hr

First Year Depreciation & Interest 199.65 $/hr

Cycle Time 18.50 seconds/part

Total Hourly Cost 236.54$ $/hr

Net Productivity 171 parts/hour

Total Laser Welding Cost per part 1.38$ $/part

Modify the Base Case Elements

• Add Seam Trackers ($100k)

• Increase Welding Speed to 9m/min

• Modify load sequence

• No Other Changes

blank travel plasma light

assist gas nozzle

helium assist gas

focus mirror

flat mirror

welding laser

beam input

focusing beam

fiber optic to detectors

collimator

visible laser

tracking

camera

output to control

Modified Cycle Time Elements* - one of two stations @ 9 m/min weld speed- 1. Pick & Place Part A 2. Index Part A Into Fixture 3. Clamp Part A 4. Pick & Place Part B 5. Stage Part B to Part A 6. Clamp Part B 7. Cycle Start 8. Weld Head Move into Position 9. Weld (part length / travel speed) 10. Cycle Stop 11. Unclamp Fixture 12. Switch Beam to Station 2 13. Lift Welded Part & Exit 14. Retract Fixture



• Same parts on each clamp

• Operators need improved timing

Modified Cycle Time Elements* - both stations @ 9 m/min weld speed-


* Example Values Only

Impact of Seam Tracking • 37% Increase in productivity

• 27% Cost Reduction per part

• $1.01 vs $1.38 per part




Upgrade the Laser • Replace the 6kW CO2 Laser with 8 kW fiber-

delivered laser (disc or fiber laser)

• Eliminate helium gas shielding

• Eliminate beam switch time

• Keep seam tracking

• Increase welding speed to 12 m/min

• No net increase in system cost, i.e. assumes alternate initial design with this laser

Fiber-Delivered Cycle Time Elements* - one of two stations @ 12 m/min weld speed-

1. Pick & Place Part A 2. Index Part A Into Fixture 3. Clamp Part A 4. Pick & Place Part B 5. Stage Part B to Part A 6. Clamp Part B 7. Cycle Start 8. Weld Head Move into Position 9. Weld (part length / travel speed) 10. Cycle Stop 11. Unclamp Fixture 12. Switch Beam to Station 2 13. Lift Welded Part & Exit 14. Retract Fixture



• Clamp functions and manual loading become greater portions of cycle time.

Fiber-delivered, 8kW Laser* - both stations @ 12 m/min weld speed-


Impact of Change to 8kW Fiber-Delivered Laser

• 54% Increase in Productivity

• 39% Reduction in Cost/Part




Summary Conclusions

• Fiber-delivered (1 um) lasers are a better choice for laser blank welding.

• Strong return on welding system performance can be achieved with improved process precision.

• Understanding the true cost and value of production solutions requires detailed analysis.

w w w . a u t o s t e e l . o r g

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