Welding ProductivityPresented by Robert Fox

Marketing Specialist @ Hobart Brothers LLC

Topics of Discussion

• Components of Weld Cost

• Components of Cycle Time

• Calculating Weld Cost & Cycle Time

• Information Gathering

• Reducing Weld Cost & Cycle Time

• Process Optimization

• Metal Cored Wires

Not All Processes are Created Equal!

Different Processes Can Produce Equal (Acceptable) Quality.

Different Processes Don’t Produce Equal (Competitive) Weld Time.

Left to Right: SMAW, GTAW, FCAW, GMAW (Solid

Wire), GMAW (Metal Cored Wire)

Contributors to Weld Cost: Identification & Measurement

Components of Weld Cost

Labor

85%

Filler Metals

10%

Shielding Gas

3%

Power

2%

Labor

Filler Metals

Shielding Gas

Power

Components of Weld Labor Cost

Pre-Weld

12%

Arc-On

31%

Arc-Off

30%

Post-Weld

12%

Filler Metals

Shielding Gas

Power

Pre-Weld

Arc-On

Arc-Off

Post-Weld

Components of Weld Labor Cost

Phase Examples Value Added?

Pre-Weld • Mill Scale/Coating Removal

• Anti-Spatter Application

• Preheat Application

• Pre-cambering

• Repair

• Fixture Loading

• Part Movement

No

Arc-On Welding Yes

Arc-Off • Slag/Silicon Removal

• Interpass Temperature

• Part Movement

• Interpass Repair

• Consumable Changeover

• Air Movement

No

Post-Weld • Slag/Silicon Removal

• Spatter Removal

• Weld Finishing

• PWHT?

• Repair

• Part Distortion

• Weld Quality

• Fixture Unloading

• Part Movement

No

Determining Weld Cost

Example Spreadsheet is Available(Includes Calculation Formulas)

Data to Collect: Be Methodical!

“Fixed” Costs

Filler Metals

Shielding Gas

Power

Labor & Overhead

Procedure

Amperage

Voltage

Travel Speed

Flow Rate

Deposition Efficiency

Power Supply Efficiency

Geometry

Weld Size

Included Angle

Root Opening

Root Face

Convexity/Concavity

Weld Length

Number of Welds

Time

Pre-Weld Time

Arc-On Time

Arc-Off Time

Post-Weld Time

Tools of the Trade: Measuring Arc Time

Simple Enhanced Integrated

Determine Where the Bottleneck Is!

• Welding IS Bottleneck:

• Improve throughput (☺)

• More parts out the door!

• Shift bottleneck elsewhere: be prepared to continue process improvement ()

• Welding is NOT the Bottleneck:

• Can make downstream bottlenecks worse ()

• Parts will stack up…

• Can starve upstream processes ()

• Weld cells will idle

Forming

Fit Up

Welding

Inspection

Paint

Reduce Arc-On Time

↑ WFS (SMAW = Amps)

↑ Deposition Rate

↑ Travel

Speed ↓ # of Passes

↓ Arc-On Time

Increased Output

$AVINGS

Operator Factor

• Definition

• The ratio of the amount of time a welding operator spends welding to the total welding operation time

• Operator Factor (%) = Arc-On Time/Total Time x 100

• Process (Total) Time = Arc-On Time/Operator Factor

SMAW GMAW-MC

Arc-Off 22.5 3.9

Arc-On 26.2 9.2

0

10

20

30

40

50

60

Tim

e (

Min

ute

s)

6” Pipe Root to Cap Total Process Time:

Arc-On Time vs. Arc-Off Time

Arc-On Arc-Off

Increasing Operator Factor & Productivity

• Process Selection• Example: Slag vs. No Slag• Example: 1G/1F vs. 3G/3F

• Parameter Selection

• Eliminate NVA activities• Slag removal, pre & post-weld

cleanup, etc.

• Capital Investment• Automation & mechanization• Work motion/positioning

• Welding Parameters: in-position vs. out-of-position

• Cell designSMAW FCAW GMAW-SW GMAW-MC

Arc-Off 22.5 5.3 6.5 3.9

Arc-On 26.2 13.2 10.9 9.2

0

10

20

30

40

50

60

Tim

e (

Min

ute

s)

6” Pipe Root to Cap Total Process Time:

Arc-On Time vs. Arc-Off Time

Arc-On Arc-Off

Shielding Gas Consumption & Cost

• Typical Shielding Gas Cost =

• Arc-On Time (Hours) * Flow Rate (Cubic Feet per Hour) * Shielding Gas Cost ($/Cubic Foot)

• Consider weldment, pre- & post-weld purge similarly

• Gas Cost per Cylinder ($/ft3)

• (Pressure (psi) * Cylinder Volume (ft3)/(14.7(psi) * Cylinder Cost)

Shielding Gas Price Influencers

• Gas Composition

• As argon content increases, so does price

• REMEMBER: use consumable features to reduce LABOR cost

• Delivery System Type & Condition

• Point of Use Size

• Point of Use vs. Bulk Systems

• Account Volume

Composition

Example Price

(per 300-Size

Cylinder)

Example Price

($/ft3)

90% Argon

10% Carbon

Dioxide

$70.02 0.298

75% Argon

25% Carbon

Dioxide

$53.00 0.226

100% Carbon

Dioxide$48.17 0.205

Filler Metals

10%

Shielding Gas

3%

Power

2%

Filler Metal Price Influencers

• Process/Type• Example: Solid Wire vs. Flux Cored Wire

vs. Seamless Flux Cored Wire

• Product Capabilities/Positioning• Improved features often requires unique

formulations• REMEMBER: use consumable features

to reduce LABOR cost

• Diameter• As diameter decreases, cost increases

• Packaging: Spools vs. Coils vs. Drums• Consider changeover cost!

• Account Volume

Filler Metal Changeover Cost

Filler Metal Consumption & Cost

• Step 1: Calculate Weld CSA

• Step 2: Calculate Weld Volume (Weld CSA * Weld Length)

• Step 3: Calculate Weld Weight (Weld Volume * Weld Density)

• Aluminum Density = ~0.096 lbs/in3

• Steel Density = ~0.283 lbs/in3

• Step 4: Calculate Filler Metal Consumption

• Weld Weight/Deposition Efficiency

Filler Metal Cost Influencers

• Weld Size

• Consider over-welding scenarios

• 1/4” = 0.03125 in^2

• 5/16” = 0.0488 in^2

• 16/25 = 65

• +56% !

• Weld Length

• Consider over-welding scenarios

• Deposition Efficiency

Filler MetalCost Influencers

Consider Joint Type Consider Included Angle

0.000

0.500

1.000

1.500

2.000

2.500

3.000

3.500

4.000

0.5 0.75 1 1.25 1.5

Cro

ss-S

ecti

on

al A

rea

(in

^2

)

Material Thickness (in.)

Included Angle vs. Cross-Sectional Area(0.125" Root Opening, 0.0625" Root Face)

60 deg. Included Angle 45 deg. Included Angle

0.000

0.500

1.000

1.500

2.000

2.500

3.000

3.500

4.000

0.5 0.75 1 1.25 1.5

Cro

ss S

ecti

on

al A

rea

(in

^2

)

Material Thickness (in.)

Joint Design vs. Cross Sectional Area(0.125" Root Opening, 0.0625" Root Face, 60°

Included Angle)

Double V Single VSingle Double

Calculating Weld Cross Sectional Area

Divide the Weld into Primitive Geometric Shapes

Deposition Efficiency = Weight Deposited/Weight Used

Power Consumption & Cost

• Welding Power (Kilowatts)

• (Amps * Volts)/(Power Supply Efficiency * 1000)

• Power Supply Efficiency

• Inverters are more efficient (~85%)

• Welding Power Consumption (KWH)

• Welding Power * Weld Time (Hours)

• Idle Power Consumption is non-negligible!

Suggested Reading

• WELDING HANDBOOK VOLUME 1 - WELDING AND CUTTING SCIENCE AND TECHNOLOGY (AWS

WHB-1.10)

• The American Welding Society

• Print—ISBN: 978-1-64322-014-7 PDF—ISBN: 978-1-64322-015-4

• PRINICIPLES OF INDUSTRIAL WELDING• The James F. Lincoln Arc Welding

Foundation

• ISBN: 0-937390-17-8

Metal Cored Wires

The Manufacture of Metal Cored Wires

Metal Cored Wire Benefits

How Metal Cored Wire Works

↓ Conductive Area

↑ Current Density

↑ Wire Feed Speed

↑ Deposition Rate

Deposition Rate Comparison

0

5

10

15

20

25

30

35

40

45

400 A 500 A 600 A 700 A 800 A

De

po

siti

on

Rat

e (

lbs/

hr)

3.2 MM SW 3.2 MM MC 4.0 MM SW 4.0 MM MC

Penetration Profile Comparison

Metal Cored Wire Solid Wire

Penetration Profile Advantages

Wire Placement Forgiveness Improved Gap Bridging

Wire Placement

Metal Cored Wire Solid Wire

Gap Bridging Capability

Metal Cored Wire Solid Wire

Suggested Reading

• WELDING HANDBOOK VOLUME 2 - PART 1: WELDING PROCESSES (AWS WHB-2.9)

• The American Welding Society

• A5.18/A5.18M:2017 ERRATA SPECIFICATION FOR CARBON STEEL ELECTRODES AND RODS FOR GAS SHIELDED ARC WELDING

• A5.28/A5.28M:2020 SPECIFICATION FOR LOW-ALLOY STEEL ELECTRODES AND RODS FOR GAS SHIELDED ARC WELDING

AWS Certified Welding Supervisor

Questions & Discussion

Thank You!