Does a second lamp really double the speed?

For identical stations, yes, and the arithmetic is simple enough to be suspicious of: a part passing under two 10-inch zones gets 20 inches of exposure, so at the same dwell requirement it can travel twice as fast. The caveats are that the stations must be genuinely identical in output and zone length, and that the parts must pass under both. A tunnel where a fixture shadows the second station does not deliver the second dose.

Why is my measured dose lower than this page predicts at that speed?

Usually the cure zone. The useful zone is where irradiance is high enough to contribute, and it is shorter than the housing: often substantially. Using the housing length overstates the achievable speed directly and proportionally. Measuring with a puck at speed settles it, because the puck integrates whatever the zone actually is.

Should I run at the speed this gives?

No. It is the speed at which the dose is exactly met, which means zero margin for the lamp's decline. Run below it by whatever your radiometer check interval justifies, and use the exposure-time page to size that margin explicitly. A line commissioned at the ceiling is undercured before the next inspection.

How is this different from the dwell-time page?

They share a formula and answer opposite questions. This page asks what speed the line could reach and what buying another station would do: a design and capital question. The dwell page starts from the line you have and asks whether its exposure is adequate: an operations question. Keeping them apart is deliberate: they were near-duplicates in the earlier version and giving them the same inputs would have kept them competing rather than complementary.

What limits the slow end of the range?

Overcure and heat. Some coatings embrittle or yellow with excess dose, and on a mercury line the infrared load rises with dwell, so a heat-sensitive substrate distorts long before the UV overcures it. The cure window page handles the two-sided speed range and the heat load page sizes the thermal side.

Does belt width matter?

Not to this calculation, but to whether the calculation applies. Irradiance falls towards the edges of the illuminated width, so a centre-line reading overstates what a wide part's edges receive, and the speed derived from it undercures those edges. The uniformity page measures that falloff; if the cross-belt spread is significant, size the speed on the coldest reading rather than the centre.

UV Curing calculator

UV Conveyor Belt Speed Calculator (Dose-Limited)

Find the fastest the belt can run and still cure. Enter the required dose, the useful cure-zone length of one lamp station, the irradiance measured at belt height, and how many stations a part passes under. The calculator returns the maximum belt speed, the dwell that dose demands, the total cure zone, the line output at that speed, and, the number worth knowing before anyone slows production, how much speed one more station would buy. Exposure accumulates across stations, so the relationship between lamps and speed is linear and usually cheaper than it looks.

What this calculator does

Find the fastest belt speed that still delivers the required dose, and show what an extra lamp station would buy.
Use it for setting the belt speed for a new material on an existing tunnel, sizing how many lamp stations a target line rate needs, costing a second lamp station against the production time a slow belt loses, checking whether a requested speed increase is compatible with cure, re-establishing the speed ceiling after a lamp change.
Find the fastest belt speed that still delivers the required dose, and show what an extra lamp station would buy.

Formula used

Dwell needed (s) = required dose ÷ measured irradiance
Total cure zone (in) = zone per station × number of stations
Maximum belt speed (ft/min) = total cure zone ÷ dwell needed ÷ 12 × 60
Speed gained per station = one zone ÷ dwell needed ÷ 12 × 60
Line output (ft/hr) = belt speed × 60

Inputs explained

Required dose: Cure dose the material needs, in a named spectral band.
Lamp cure-zone length: Useful illuminated length of ONE station along the direction of travel, measured where irradiance actually matters rather than housing to housing.
Measured irradiance at belt: Radiometer reading at belt height, in the same band as the dose target.
Lamp stations in the tunnel: How many identical lamp stations a part passes under. Exposure accumulates, so speed scales directly with this.

How to use the result

Best suited to setting the belt speed for a new material on an existing tunnel, sizing how many lamp stations a target line rate needs, costing a second lamp station against the production time a slow belt loses, checking whether a requested speed increase is compatible with cure, re-establishing the speed ceiling after a lamp change.
Assumes identical stations; a tunnel mixing lamp types needs the multi-lamp dose page, which sums measured contributions instead. Ignores the gaps between stations, which matter for temperature but not for accumulated dose. Does not model surface cure, which follows peak irradiance and can fail at a speed this page passes. Says nothing about the lower speed limit. Overcure, yellowing and substrate heating bound the window from the other side. Assumes a flat part presenting one surface; shaped parts shadow, which the shadowing page covers.

Common questions

Does a second lamp really double the speed? For identical stations, yes, and the arithmetic is simple enough to be suspicious of: a part passing under two 10-inch zones gets 20 inches of exposure, so at the same dwell requirement it can travel twice as fast. The caveats are that the stations must be genuinely identical in output and zone length, and that the parts must pass under both. A tunnel where a fixture shadows the second station does not deliver the second dose.
Why is my measured dose lower than this page predicts at that speed? Usually the cure zone. The useful zone is where irradiance is high enough to contribute, and it is shorter than the housing: often substantially. Using the housing length overstates the achievable speed directly and proportionally. Measuring with a puck at speed settles it, because the puck integrates whatever the zone actually is.
Should I run at the speed this gives? No. It is the speed at which the dose is exactly met, which means zero margin for the lamp's decline. Run below it by whatever your radiometer check interval justifies, and use the exposure-time page to size that margin explicitly. A line commissioned at the ceiling is undercured before the next inspection.
How is this different from the dwell-time page? They share a formula and answer opposite questions. This page asks what speed the line could reach and what buying another station would do: a design and capital question. The dwell page starts from the line you have and asks whether its exposure is adequate: an operations question. Keeping them apart is deliberate: they were near-duplicates in the earlier version and giving them the same inputs would have kept them competing rather than complementary.
What limits the slow end of the range? Overcure and heat. Some coatings embrittle or yellow with excess dose, and on a mercury line the infrared load rises with dwell, so a heat-sensitive substrate distorts long before the UV overcures it. The cure window page handles the two-sided speed range and the heat load page sizes the thermal side.

Last reviewed 2026-08-25.