 What Percentage of Welding Cost is
Shielding Gas? |
| Unfortunately most published welding cost calculations are based on an incorrect
assumption that shielding gas usage is the flow rate set on a
flowmeter times the welding time! After understanding the data in this website and looking at
your real costs you realize this is an erroneous assumption! |
|
First, evaluating what is typically published:
General Assumptions:
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- 0.035 diameter solid wire operating at 190 amps. That
deposits 5.5 lbs/hr when the arc is on. Assume wire cost is $0.85/pound
- 30 CFH Shielding Gas flow. Assume cost of $0.10/cubic foot
for an argon based gas
(= $10.00/100 cubic feet)
- Direct Labor cost = $18.00/ hour
- Labor Overhead = 30% of Labor cost
|
 |
NO Gas Waste Case: With
the above assumptions and no consideration for shielding gas
waste, the resulting weld cost pie chart is shown on the
left. This is what is typically published as the method of calculating
shielding gas costs. |
| Shielding gas is shown as only 5 % of total cost and less than
wire costs which are 7%. This is based on an
unrealistic assumption of no gas waste. |
 |
High Waste Case: To evaluate a high waste case, assume gas waste
is the high end defined in the literature, i.e. gas usage is, 30 CF/ lb of wire
(SEE References) with a high duty
cycle. |
| Shielding gas would now be 32% of welding costs!
Probably higher than actual unless your welders are also setting much
to high a flow rate. |
| BOTTOM LINE: Consider your real
gas usage when
estimating the cost of shielding gas not a calculation based on an unrealistic
assumption! |
|
The Calculations are
Covered in
"Lean Welding Manufacturing-Shielding
Gas"
Learning Program
"Optimizing Shielding Gas
Use and Eliminating Waste" includes details of this information in a
Do-It-Yourself 7 Module Program
It quantifies waste due to surge flow, leaks, ways to monitor
leaks and the gas flow settings where air is pulled into the shielding stream.
Unfortunately many are using far too much gas flow, wrongly employing the
philosophy, "If Some is Good More Must be Better" !
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