Estimate welding cell yield loss by comparing all completed parts with the quantity accepted as good output. The calculator returns the rejected count, loss percentage, first-pass yield, and an optional reject-cost estimate.
The metric is useful for tracking weld defects, dimensional failures, incomplete joints, or other quality outcomes that prevent a produced part from passing acceptance. A consistent definition of ‘good’ is essential; changing inspection criteria between periods can change the measured loss even when the physical process has not changed.
Inputs
parts
parts
USD
Result
—
yield loss rate
Rejected parts—
First-pass yield—
Estimated reject cost—
1. Enter total welded output Use all parts completed by the cell during the selected batch or period.
2. Enter accepted good parts Use the same counting boundary and include only units meeting the chosen quality standard.
3. Enter optional reject cost Add a per-rejected-part estimate if you want a simple cost impact; zero is allowed.
4. Read yield loss The main percentage is rejected units as a share of total welded output.
5. Compare with first-pass yield Use the complementary yield result to track how much output passes without being classified as rejected.
Formula:
Rejected parts = Total welded parts − Good parts
Yield loss rate = Rejected parts ÷ Total welded parts × 100
First-pass yield = Good parts ÷ Total welded parts × 100
Estimated reject cost = Rejected parts × Cost per rejected part
All counts must cover the same process boundary. The optional cost is multiplied directly by rejected quantity and does not separately model rework recovery or salvage value.
If reworked parts are tracked, decide whether this metric is first-pass yield loss or final scrap loss and classify parts consistently.
What the result means
The result is the percentage of completed welded parts that did not qualify as good output under the selected quality definition.
Use defect categories alongside the loss rate when you need to identify the specific welding conditions driving rejects.
Given: 600 welded parts, 574 accepted good parts, and an estimated $18 cost for each rejected part.
Result: Yield loss is 4.33%, representing 26 rejected parts and about $468 in entered reject cost.
The loss percentage can be trended across shifts or jobs as long as the same acceptance and rework rules are used.
Should rework be counted as reject loss?
For first-pass yield, a part that requires rework is normally not first-pass good. For final scrap loss, you may instead count successfully recovered parts as good; state which definition you are using.
Can good count equal total count?
Yes. In that case yield loss is 0% and first-pass yield is 100% for the selected period.
What should the reject cost include for welded assemblies?
It can be a simple material-and-labor estimate or a fuller internal burdened cost. Use the same definition over time if you want comparable cost trends.
Does this calculator identify the cause of welding defects?
No. It quantifies the output loss; root-cause analysis still requires defect coding and process investigation such as parameter, fit-up, fixture, consumable, or operator review.
How does yield loss relate to OEE quality?
OEE quality uses good count divided by total count. Under the same counting rules, this calculator’s first-pass yield is the same quality ratio, while yield loss is its rejected share.