How is this different from the conveyor speed page?

They share physics and answer opposite questions. This page starts from the line you have: its zone, its speed, and asks whether it is adequate. The conveyor speed page starts from a requirement and asks what speed a line could reach, including what another lamp station would buy. In the earlier version both computed dose over irradiance and neither asked the other's question, which is why they read as duplicates. Keeping them apart is the point.

Why does the page need irradiance if the earlier version did not?

Because without it the page is a units conversion. Cure zone divided by speed gives seconds, and seconds tell you nothing about whether a part cured: dose does, and dose needs irradiance. the earlier version's version could compute a dwell and apply a safety margin to it without ever knowing whether the result cured anything, which made the margin decorative.

My margin is fine but parts are tacky. Why?

Almost certainly oxygen inhibition rather than dwell. Air quenches radicals in the top few microns of an acrylate, leaving an uncured skin over a properly cured bulk, and it is beaten by peak irradiance rather than by time. Adding dwell at the same irradiance often does not fix it. The oxygen inhibition page models that directly.

Can I use the maximum speed as my setpoint?

No. It is the speed at which the dose is exactly met, so it carries zero margin for the lamp's decline. Run below it by enough to survive the interval between radiometer checks, which is what the dose margin page sizes. A line commissioned at the ceiling is undercured before anyone measures again.

What if the cure zone is not uniformly illuminated?

Then this page overstates the dose, because it multiplies the peak irradiance by the full dwell. Real zones ramp up and down at their ends, so the integrated dose is lower than peak times dwell. A radiometer puck run through the process integrates the real profile and is the right check whenever the margin looks close.

Does belt width matter?

Not to the arithmetic, but to whether the arithmetic applies. Irradiance falls towards the edges of the illuminated width, so a centre-line reading overstates what a wide part's edges receive. If the cross-belt spread is significant, run this page against the coldest reading rather than the centre one: the uniformity page measures that spread.

UV Curing calculator

UV Dwell Time Calculator: Is Your Line Fast Enough?

Find out what dwell your line actually gives and whether it is enough. Enter the useful cure-zone length, the belt speed you run today, the material's cure-dose requirement and the irradiance measured at belt height. The calculator returns the dwell the line produces, the dose that dwell delivers, the margin over requirement, the dwell the dose demands, and the fastest speed that still cures. The conversion from speed to seconds is the easy half; the half that matters is whether the seconds are enough.

What this calculator does

Turn the cure zone and belt speed you already run into the dwell and dose the line actually delivers, and say whether that clears the requirement.
Use it for checking whether an existing line speed cures a new material, diagnosing an undercure complaint from the line's actual settings, finding how much speed a comfortable margin is leaving unclaimed, confirming a speed change is safe before making it permanent, re-checking a line after a lamp replacement.
Turn the cure zone and belt speed you already run into the dwell and dose the line actually delivers, and say whether that clears the requirement.

Formula used

Belt speed (in/s) = belt speed (ft/min) × 12 ÷ 60
Dwell the line gives (s) = cure-zone length ÷ belt speed in in/s
Dose delivered = measured irradiance × dwell
Margin = (dose delivered − required dose) ÷ required dose × 100
Dwell required = required dose ÷ measured irradiance
Fastest belt speed = cure zone ÷ dwell required ÷ 12 × 60

Inputs explained

Lamp cure-zone length: Useful illuminated length along the direction of travel. Measure where irradiance matters, not housing to housing.
Conveyor belt speed: The speed the line runs at today.
Required cure dose: The material's cure-dose requirement, in a named spectral band.
Measured irradiance at belt: Radiometer reading at belt height in the same band. This is what turns a dwell into a dose.

How to use the result

Best suited to checking whether an existing line speed cures a new material, diagnosing an undercure complaint from the line's actual settings, finding how much speed a comfortable margin is leaving unclaimed, confirming a speed change is safe before making it permanent, re-checking a line after a lamp replacement.
Single station. A multi-lamp tunnel accumulates dose across stations; the conveyor-speed and multi-lamp pages cover that. Surface dose only. Nothing here describes what reaches the bottom of a pigmented or thick film. Does not model oxygen inhibition, which can leave a tacky surface at a dwell the bulk cured at. One-sided: it protects against undercure and treats large margins as informational, though overcure and substrate heat are real limits. Assumes a flat part presenting one surface; shaped parts shadow themselves.

Common questions

How is this different from the conveyor speed page? They share physics and answer opposite questions. This page starts from the line you have: its zone, its speed, and asks whether it is adequate. The conveyor speed page starts from a requirement and asks what speed a line could reach, including what another lamp station would buy. In the earlier version both computed dose over irradiance and neither asked the other's question, which is why they read as duplicates. Keeping them apart is the point.
Why does the page need irradiance if the earlier version did not? Because without it the page is a units conversion. Cure zone divided by speed gives seconds, and seconds tell you nothing about whether a part cured: dose does, and dose needs irradiance. the earlier version's version could compute a dwell and apply a safety margin to it without ever knowing whether the result cured anything, which made the margin decorative.
My margin is fine but parts are tacky. Why? Almost certainly oxygen inhibition rather than dwell. Air quenches radicals in the top few microns of an acrylate, leaving an uncured skin over a properly cured bulk, and it is beaten by peak irradiance rather than by time. Adding dwell at the same irradiance often does not fix it. The oxygen inhibition page models that directly.
Can I use the maximum speed as my setpoint? No. It is the speed at which the dose is exactly met, so it carries zero margin for the lamp's decline. Run below it by enough to survive the interval between radiometer checks, which is what the dose margin page sizes. A line commissioned at the ceiling is undercured before anyone measures again.
What if the cure zone is not uniformly illuminated? Then this page overstates the dose, because it multiplies the peak irradiance by the full dwell. Real zones ramp up and down at their ends, so the integrated dose is lower than peak times dwell. A radiometer puck run through the process integrates the real profile and is the right check whenever the margin looks close.

Last reviewed 2026-08-25.