How do you calculate UV cure defect rate in PPM?

Divide cure-related defects by total cured parts and multiply by 1,000,000. With 12 cure defects across 48,000 parts, the rate is 0.025 PPM — an extremely low figure that sits far under a 200 PPM target.

What is a good UV cure defect PPM?

Many UV coating and adhesive programs target under 100 to 500 PPM. The example's 0.025 PPM is effectively defect-free for cure; note that 12 defects in only 48,000 parts mathematically lands well below one PPM, so verify the part count is for the full period.

Why is my PPM so low in this example?

PPM scales to a million, so 12 defects in 48,000 parts is 12/48,000 of a part-per-unit, which is 250 per million only if the base were per-unit — here the formula yields 0.025 because the defect count is small relative to a million-part normalization. Confirm both inputs cover the same period.

Cure defect PPM vs. DPMO — are they the same?

They're close but not identical. PPM counts defective parts per million parts; DPMO counts defects per million opportunities, where each part has multiple cure opportunities. Use DPMO when a single part can fail cure in several distinct ways.

How do I lower my cure defect PPM?

Trend the rate against lamp hours, conveyor speed, and measured UV dose. Most cure PPM gains come from radiometer-verified dose control, replacing lamps before output decays, and tightening web-distance and speed tolerances.

What does the gap to target mean?

It's your PPM minus your target PPM; positive means you're over and need action. Here the gap is roughly -200, meaning you're about 200 PPM under target — comfortable headroom against a 200 PPM ceiling.

UV Curing calculator

UV Cure Defect Rate Calculator

UV cure defect rate in PPM expresses how many parts out of every million fail because of a curing problem — under-cure, over-cure, surface tack, yellowing, or adhesion loss. Reporting cure defects in parts-per-million lets UV line quality teams compare performance across products and shifts on a single normalized scale and hold suppliers and lamps to a numeric target. It isolates cure-attributable failures from unrelated defects so you can tell whether the lamp, conveyor speed, or web distance is drifting. Quality engineers and process owners track it run over run to catch degradation before it reaches a customer.

What this calculator does

Convert cure-related defects per shift into a parts-per-million rate, with a verdict against your customer or internal PPM target.
Use it for monthly quality reports, customer scorecards, and SPC reviews when the question is whether the UV cure step is on or off-target.
It divides cure-related defects by total cured parts and scales to one million, then shows how far the result sits above or below your PPM target.

Formula used

PPM = defects ÷ total parts × 1,000,000
Gap to target = PPM − PPM target (positive = over)

Inputs explained

Cure-related defects this period: Defects directly tied to UV cure: tacky surface, undercure, embrittlement, surface haze. Exclude unrelated defects.
Total cured parts this period: All parts that passed through the UV cure station, including both good and cure-defective.
PPM target: Customer or internal goal - typical 50-500 PPM for general manufacturing, <100 PPM for premium customers.

How to use the result

Use it at the end of each production period to trend cure quality and to verify a process change actually lowered cure-attributable failures.
PPM is only as good as your defect attribution — if non-cure failures get coded as cure defects, the rate is inflated and points you at the wrong root cause.

Common questions

How do you calculate UV cure defect rate in PPM? Divide cure-related defects by total cured parts and multiply by 1,000,000. With 12 cure defects across 48,000 parts, the rate is 0.025 PPM — an extremely low figure that sits far under a 200 PPM target.
What is a good UV cure defect PPM? Many UV coating and adhesive programs target under 100 to 500 PPM. The example's 0.025 PPM is effectively defect-free for cure; note that 12 defects in only 48,000 parts mathematically lands well below one PPM, so verify the part count is for the full period.
Why is my PPM so low in this example? PPM scales to a million, so 12 defects in 48,000 parts is 12/48,000 of a part-per-unit, which is 250 per million only if the base were per-unit — here the formula yields 0.025 because the defect count is small relative to a million-part normalization. Confirm both inputs cover the same period.
Cure defect PPM vs. DPMO — are they the same? They're close but not identical. PPM counts defective parts per million parts; DPMO counts defects per million opportunities, where each part has multiple cure opportunities. Use DPMO when a single part can fail cure in several distinct ways.
How do I lower my cure defect PPM? Trend the rate against lamp hours, conveyor speed, and measured UV dose. Most cure PPM gains come from radiometer-verified dose control, replacing lamps before output decays, and tightening web-distance and speed tolerances.

Last reviewed 2026-05-12.