Can I fix a shadowed recess with more lamp power?

Only where the shortfall is small. The floor dose scales with the view factor, so doubling it means doubling the dose on every open face.

What actually works for deep features?

Change the geometry or the chemistry: cure before the feature is enclosed, add a second head at an angle, or use a dual-cure adhesive in the recess.

Why does depth matter more than width?

The view factor has depth squared in the denominator, so once depth exceeds the opening radius the fraction falls away quickly.

Does oxygen inhibition make this worse?

Usually, and the two compound. A still recess lets oxygen replenish at the surface, raising the dose the floor needs while the geometry cuts what it gets.

UV Curing calculator

UV Shadowing Calculator: Does the Bottom of the Recess Cure?

Work out whether the bottom of a pocket, slot or bore receives enough UV to cure. Enter the opening width, depth, flat-surface dose and the material's required dose.

What this calculator does

Estimate the dose reaching a recess floor from its geometry, and whether it clears the requirement.

Formula used

Opening radius = opening width ÷ 2
View factor = radius² ÷ (radius² + depth²)
Dose reaching the recess floor = flat-surface dose × view factor
Recess margin (%) = (floor dose − required) ÷ required × 100
Flat-surface dose needed = required dose ÷ view factor

Inputs explained

Recess Opening Width: Clear width of the opening at the surface.
Depth to the Surface Cured: Distance from the opening down to the surface that must cure.
Dose on the Flat Surface: Measured dose on an unobstructed face in the same pass.
Required Cure Dose: What the coating or adhesive needs, in the measured band.

How to use the result

Best suited to deciding at design review whether a pocket cures, explaining why a bore fails, testing whether lamp power can fix a shadow.
A geometric estimate, not a measurement; confirm with a probe or dose strip. A collimated or off-axis source delivers less than the view factor suggests. Ignores wall reflections and oxygen inhibition, which can help or hurt.

Common questions

Can I fix a shadowed recess with more lamp power? Only where the shortfall is small. The floor dose scales with the view factor, so doubling it means doubling the dose on every open face.
What actually works for deep features? Change the geometry or the chemistry: cure before the feature is enclosed, add a second head at an angle, or use a dual-cure adhesive in the recess.
Why does depth matter more than width? The view factor has depth squared in the denominator, so once depth exceeds the opening radius the fraction falls away quickly.
Does oxygen inhibition make this worse? Usually, and the two compound. A still recess lets oxygen replenish at the surface, raising the dose the floor needs while the geometry cuts what it gets.

Related guides

Last reviewed 2026-10-01.