How do you calculate a UV shadowing risk score?

Multiply geometry severity by 0.5, fixture/lane risk by 0.3 and beam-angle/speed risk by 0.2, then add them. With 55, 30 and 20 that gives 27.5 + 9 + 4 = 37.5, a medium-risk result.

What is a good UV shadowing risk score?

Below 30 is low risk and usually needs no extra profiling. 30-60 is medium and warrants a confirmation reading in the shadowed area. 60 or above is high and should not run until you have verified dose with a radiometer.

Why is geometry weighted the highest?

Deep pockets, tall bosses and undercuts physically block the UV line-of-sight regardless of how good your fixturing or beam angle is, so geometry (0.5) dominates the score. A part that is 90 on geometry is hard to save with fixturing alone.

How do I lower a high shadowing risk score?

Add a second lamp at an offset angle, rotate or index the part mid-cure, switch to a diffuse or focused reflector, or re-design the fixture so it stops occluding the joint. Each of these attacks one of the three input terms.

Shadowing risk score vs a direct radiometer reading?

The score is a fast triage tool you can run before setup; a radiometer reading is the ground truth of delivered dose. Use the score to decide where and whether to spend the time taking the reading.

Does a low score mean the shadowed area is fully cured?

No. A low score means the geometry, fixturing and beam angle are unlikely to cause a shadow problem, but final cure still depends on dose, line speed and formulation. Confirm any safety-critical bond regardless of score.

UV Curing calculator

UV Shadowing Risk Calculator

The UV Shadowing Risk Score is a weighted, FMEA-style index that tells a UV curing engineer how likely recessed features, undercuts and fixture-blocked areas are to receive insufficient dose. Process engineers and quality teams on conveyor and press-side curing lines use it to decide where a follow-up radiometer profiling pass is worth the downtime. It matters because a part can pass a surface tack test while adhesive or coating in a shadowed pocket stays undercured, showing up weeks later as delamination or a field failure. Rather than treating every shadowed geometry as equally dangerous, the score ranks risk so you spend confirmation effort where it actually pays off.

What this calculator does

Score the cure risk on parts with 3D geometry, undercuts, or fixturing that blocks line-of-sight from the UV lamp.
Use it during DFM review of a new part, or when a defect spike traces to specific features (a bonded edge under a flange, an undercut adhesive joint).
It computes a single shadowing risk score by weighting geometry severity at 0.5, fixture/lane occlusion at 0.3 and beam-angle/speed detectability at 0.2.

Formula used

Risk score = (geometry × 0.5) + (fixture × 0.3) + (exposure × 0.2)
Score 0-30 low, 30-60 medium, 60+ high - schedule a confirmation pass with a profiling radiometer in shadowed areas.

Inputs explained

Part geometry shadow severity:
Fixture / conveyor lane occlusion risk:
Beam angle & line-speed detection risk:

How to use the result

Use it during process qualification of a new part or fixture, after a lamp or reflector change, or whenever a shadowed pocket is suspected of undercuring.
It ranks relative risk from your subjective 0-100 inputs; it is not a substitute for a profiling radiometer reading of the actual dose in the shadowed zone.

Common questions

How do you calculate a UV shadowing risk score? Multiply geometry severity by 0.5, fixture/lane risk by 0.3 and beam-angle/speed risk by 0.2, then add them. With 55, 30 and 20 that gives 27.5 + 9 + 4 = 37.5, a medium-risk result.
What is a good UV shadowing risk score? Below 30 is low risk and usually needs no extra profiling. 30-60 is medium and warrants a confirmation reading in the shadowed area. 60 or above is high and should not run until you have verified dose with a radiometer.
Why is geometry weighted the highest? Deep pockets, tall bosses and undercuts physically block the UV line-of-sight regardless of how good your fixturing or beam angle is, so geometry (0.5) dominates the score. A part that is 90 on geometry is hard to save with fixturing alone.
How do I lower a high shadowing risk score? Add a second lamp at an offset angle, rotate or index the part mid-cure, switch to a diffuse or focused reflector, or re-design the fixture so it stops occluding the joint. Each of these attacks one of the three input terms.
Shadowing risk score vs a direct radiometer reading? The score is a fast triage tool you can run before setup; a radiometer reading is the ground truth of delivered dose. Use the score to decide where and whether to spend the time taking the reading.

Last reviewed 2026-05-12.