How do you calculate sheet metal housing yield?

Divide accepted first-pass housings by total housings fabricated and multiply by 100. With 92 accepted out of 100 fabricated, yield is 92%.

What is a good first-pass yield for welded fan housings?

Mature fabrication cells typically run 94-98% first-pass on housings. At 92% with a 96% target, this shop sits 4 points short, meaning about 4 extra housings per 100 are hitting rework or scrap.

What does the housing yield gap to target tell me?

It is the points difference between actual and target yield. Here it is 4 points (92% vs 96%), quantifying exactly how much improvement closes the gap before you celebrate.

Why use first-pass yield instead of final yield?

Final yield can hide a lot of rework, since reworked parts eventually pass. First-pass yield exposes the true cost of weld repair, re-flattening and re-trimming, which is where housing margin actually leaks.

What usually drives fan housing rejects?

Most first-pass rejects trace to weld porosity and burn-through on the scroll seam, out-of-flat mounting flanges, and dimensional drift in formed inlet cones. Fixture wear and inconsistent blank flatness are common root causes.

How many good housings am I getting from 100 starts?

At 92% yield, 92 of every 100 fabricated housings pass first time and 8 need rework or scrap. Closing the 4-point gap to the 96% target would recover roughly 4 more clean housings per 100.

Industrial Fans, Blowers & Air Movement Equipment calculator

Sheet Metal Housing Yield Calculator

Sheet metal housing yield is the share of fan scrolls, blower casings and inlet cones that pass inspection on the first pass, with no rework or scrap. Fabrication supervisors and quality engineers at air-movement equipment makers watch it because the housing is the most material- and labor-intensive weldment in a fan, and a leaking seam or out-of-flat flange means costly rework or full scrap. Tracking first-pass yield against a target separates a stable laser-and-press cell from one quietly bleeding margin into the grinder and re-weld booth. It is the cleanest early signal that your blanks, forming or weld fixtures have drifted.

What this calculator does

Calculate first-pass sheet metal housing yield from accepted housings, fabricated housings, and target yield.
Use it when tracking housing fabrication, welding, grinding, leak checks, fit-up, paint readiness, or scrap performance.
It computes the percentage of fan housings accepted on the first pass and the point gap between that yield and your target.

Formula used

Sheet metal housing yield = accepted fan housings first pass ÷ total housings fabricated × 100
Housing yield gap to target = sheet metal housing yield - target housing first-pass yield

Inputs explained

Accepted fan housings first pass:
Total housings fabricated:
Target housing first-pass yield:

How to use the result

Use it for daily or weekly fabrication quality reviews, after a process change to forming or welding, or when scrap costs spike.
First-pass yield counts units, not cost, so one scrapped large welded scroll weighs the same as one minor rejected bracket even though their dollar impact differs hugely.

Current U.S. benchmarks

Steel mill PPI stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. New factory orders are up 2.3% year over year (Census).

Common questions

How do you calculate sheet metal housing yield? Divide accepted first-pass housings by total housings fabricated and multiply by 100. With 92 accepted out of 100 fabricated, yield is 92%.
What is a good first-pass yield for welded fan housings? Mature fabrication cells typically run 94-98% first-pass on housings. At 92% with a 96% target, this shop sits 4 points short, meaning about 4 extra housings per 100 are hitting rework or scrap.
What does the housing yield gap to target tell me? It is the points difference between actual and target yield. Here it is 4 points (92% vs 96%), quantifying exactly how much improvement closes the gap before you celebrate.
Why use first-pass yield instead of final yield? Final yield can hide a lot of rework, since reworked parts eventually pass. First-pass yield exposes the true cost of weld repair, re-flattening and re-trimming, which is where housing margin actually leaks.
What usually drives fan housing rejects? Most first-pass rejects trace to weld porosity and burn-through on the scroll seam, out-of-flat mounting flanges, and dimensional drift in formed inlet cones. Fixture wear and inconsistent blank flatness are common root causes.

Last reviewed 2026-05-12.