UV Curing calculator
UV Dose Uniformity Calculator
A healthy average dose can hide a corner that under-cures. This calculator turns three radiometer numbers — minimum, maximum, and average across the work surface — into a percent non-uniformity and a clean read on the spread, so a process engineer can decide whether a reflector adjustment, an extra lamp, or a fixture redesign is needed before parts ship.
What this calculator does
- Quantify UV dose uniformity across a work surface from radiometer pass min, max, and average — see whether the worst spot still cures.
- Use it after a profiling pass to prove the cold corner of a fixture or belt still receives enough dose, or to justify reflector / lamp-spacing changes.
- Computes the percent non-uniformity of UV dose across the work surface, plus the absolute spread between hot and cold readings.
Formula used
- Spread = max dose − min dose (mJ/cm²)
- Non-uniformity (%) = spread ÷ average × 100
Inputs explained
- Minimum dose reading: Lowest single reading from the profiling pass — usually a corner or shadowed spot.
- Maximum dose reading: Highest single reading, typically directly under the lamp center.
- Average dose across surface: Mean of all profiling positions across the work surface.
How to use the result
- Use after every reflector or lamp-position change, after a fixture redesign, and when a defect rate spike points to localized undercure (tacky corners, edge bond failures).
- Tells you the spread but not whether the cold spot is still above the chemistry minimum — pair with the UV Dose Margin calculator using the minimum reading as 'measured dose'. Three numbers also can't reveal a hot strip down the middle; for that, log every grid point and review the full profile.
Common questions
- What non-uniformity is acceptable? Most UV process specs target ≤15% (some chemistry-critical lines tighten to ≤10%). Above 25% you usually have a real cause — a missing reflector segment, a bad lamp in a bank, parts riding too high, or a fixture that overhangs the cure zone.
- Min and max are very different but average is fine — what now? Average can lie. The right next step is to take the minimum reading from the profile and run UV Dose Margin against the chemistry's required dose. If the cold spot is below required dose × 1.0 you have a quality risk regardless of how good the average looks.
- How many grid points should I take? At least one reading per 4 in² of part footprint — typically a 5×5 or 7×7 grid for fixtures up to ~12×12 in. On conveyor lines, take readings at three lateral positions (left, center, right) along the belt direction so you catch both lamp-axis and cross-belt non-uniformity.
- How does this differ from UV Dose Mapping? This calc reduces the whole profile to one non-uniformity number — useful for capability reports and trend tracking. UV Dose Mapping is for sanity-checking the whole grid and looking for spatial patterns (rings, stripes, drop at the edges). Use both: this for the headline metric, mapping for diagnosis.
Last reviewed 2026-05-12.