How do you calculate a UV cure process window?

You run a speed ladder (a series of line speeds), test each result for full cure and adhesion, and record the slowest and fastest speeds that pass. The window is the band between them. This tool then checks whether your operating point sits inside that band, as with 32 ft/min falling between a 22 and 48 ft/min window.

What does the margin number mean?

Margin is the shortest distance from your operating point to either limit. At 32 ft/min in a 22 to 48 window the margin is 10 ft/min to the floor, so you have 10 ft/min of cushion before you risk overcure.

Is it better to run near the floor or the ceiling of the window?

Most shops target the center. Running near the undercure ceiling maximizes throughput but leaves little cushion as lamps decay; running near the overcure floor is safer for cure but can embrittle coatings and slows the line.

Why did my parts start failing even though the speed didn't change?

The window itself moves as UV lamps lose output. A speed that was comfortably inside the window at 100% lamp output can drift outside it once irradiance decays, because the same speed now delivers less dose.

What is a safe margin to the nearest limit?

There is no universal number, but many coating specs treat less than roughly 10 to 15 percent of the window width as tight. For a 26 ft/min wide window that is about 3 to 4 ft/min; a 10 ft/min margin like the example is comfortable.

Line speed window vs UV dose window, what's the difference?

A dose window is expressed in mJ/cm2 and is chemistry-specific; a line speed window converts that dose target into belt speed for your specific lamp and geometry. Speed is what the operator actually controls, so the speed window is the practical shop-floor version.

UV Curing calculator

UV Cure Window Calculator

A UV cure process window defines the band of line speeds where a coating, ink, or adhesive receives enough dose to fully cross-link without overcuring or embrittling. Process engineers and line operators use this window to confirm that today's belt speed still produces conforming parts as lamps age and jobs change. Running below the floor wastes throughput and can overcure, while running above the ceiling leaves undercured, tacky, or under-adhered product. This calculator tells you instantly whether your operating point is inside the qualified window and how much cushion you have before you hit a limit.

What this calculator does

Check whether the current line speed (or any other process variable) sits inside the validated UV cure window - and how close it is to either limit.
Use it during process changes - new SKU, lamp swap, line speed adjustment - to confirm you're still inside the validated window before releasing the change.
It reports whether your current line speed falls between the validated minimum and maximum speeds, plus the distance in ft/min to the nearest limit.

Formula used

Inside window = (window min ≤ operating point ≤ window max)
Margin = closest distance to either limit (negative = outside)

Inputs explained

Current line speed (operating point):
Slowest allowed speed (overcure floor):
Fastest allowed speed (undercure ceiling):

How to use the result

Use it at job setup, after a lamp change, or whenever an operator questions whether the current belt speed is still qualified for the coating being run.
The window is only valid for the exact lamp type, reflector condition, coating chemistry, and part geometry it was qualified with; changing any of those invalidates the min and max speeds.

Common questions

How do you calculate a UV cure process window? You run a speed ladder (a series of line speeds), test each result for full cure and adhesion, and record the slowest and fastest speeds that pass. The window is the band between them. This tool then checks whether your operating point sits inside that band, as with 32 ft/min falling between a 22 and 48 ft/min window.
What does the margin number mean? Margin is the shortest distance from your operating point to either limit. At 32 ft/min in a 22 to 48 window the margin is 10 ft/min to the floor, so you have 10 ft/min of cushion before you risk overcure.
Is it better to run near the floor or the ceiling of the window? Most shops target the center. Running near the undercure ceiling maximizes throughput but leaves little cushion as lamps decay; running near the overcure floor is safer for cure but can embrittle coatings and slows the line.
Why did my parts start failing even though the speed didn't change? The window itself moves as UV lamps lose output. A speed that was comfortably inside the window at 100% lamp output can drift outside it once irradiance decays, because the same speed now delivers less dose.
What is a safe margin to the nearest limit? There is no universal number, but many coating specs treat less than roughly 10 to 15 percent of the window width as tight. For a 26 ft/min wide window that is about 3 to 4 ft/min; a 10 ft/min margin like the example is comfortable.

Last reviewed 2026-05-12.