How do you calculate UV adhesive cure time?

Divide the required bondline dose by the measured irradiance at the joint, then add your safety margin. With 3000 mJ/cm2 at 300 mW/cm2 the base time is 10 seconds; a 30% margin gives a recommended 13 seconds.

Why add a depth-of-cure margin?

Datasheet dose is often the minimum for a thin film. Thick bondlines, pigmented or filled adhesives, and real-world irradiance drift all eat into that minimum, so a 20-40% margin keeps the bond fully cured through its depth.

What is a good cure margin percentage?

For clear, thin bonds 15-20% is common; for opaque, thick or safety-critical joints 30-50% is safer. The example uses 30%, adding 3 seconds on top of the 10-second base time.

Do I use lamp face irradiance or irradiance at the joint?

Always the irradiance measured at the joint. Face ratings overstate what the adhesive sees after distance, angle and any window or substrate losses, which would make your cure time dangerously short.

Cure time vs cure dose, what is the difference?

Dose (mJ/cm2) is the total energy the adhesive needs; cure time (seconds) is how long it takes to deliver that dose at your measured irradiance. Time equals dose divided by irradiance.

Can I just double irradiance to halve cure time?

Roughly yes, since time is inversely proportional to irradiance, but only up to the adhesive's reciprocity limit. Very high irradiance can outrun the chemistry or overheat the substrate, so verify with pull tests.

UV Curing calculator

UV Adhesive Cure Time Calculator

The UV Adhesive Bond Cure Time calculator turns a datasheet dose target and a measured irradiance at the joint into the number of seconds the bond must sit under the lamp. Adhesive and assembly engineers use it to set cure-station timers and conveyor dwell so bonds reach full strength without over-baking the substrate. It matters because cure time is dose divided by irradiance, and irradiance at the actual joint is almost always lower than the lamp's face rating once distance, angle and window losses are counted. Adding a depth-of-cure margin protects against thick bondlines and pigmented adhesives that need extra time to fully polymerize through their depth.

What this calculator does

Estimate cure time for a UV adhesive bondline at a given irradiance - including the depth-of-cure penalty for thick or pigmented beads.
Use it on assembly cells where UV adhesive is the cycle-driver and you need a defensible bond cure setpoint, not the data sheet's surface-cure number.
It divides the bondline dose target by measured irradiance to get a base cure time, then multiplies by one plus your margin for the recommended time.

Formula used

Base cure time (sec) = bondline dose target ÷ irradiance at joint
Recommended cure time = base cure time × (1 + process margin)

Inputs explained

Bondline dose target:
Measured irradiance at the joint:
Depth-of-cure / process safety margin:

How to use the result

Use it when setting a new cure-station timer, qualifying a new adhesive, or after any change to lamp distance, power or the adhesive's opacity.
It assumes irradiance is steady and measured at the actual joint; thick, filled or shadowed bondlines may still need bench-verified pull testing to confirm full through-cure.

Common questions

How do you calculate UV adhesive cure time? Divide the required bondline dose by the measured irradiance at the joint, then add your safety margin. With 3000 mJ/cm2 at 300 mW/cm2 the base time is 10 seconds; a 30% margin gives a recommended 13 seconds.
Why add a depth-of-cure margin? Datasheet dose is often the minimum for a thin film. Thick bondlines, pigmented or filled adhesives, and real-world irradiance drift all eat into that minimum, so a 20-40% margin keeps the bond fully cured through its depth.
What is a good cure margin percentage? For clear, thin bonds 15-20% is common; for opaque, thick or safety-critical joints 30-50% is safer. The example uses 30%, adding 3 seconds on top of the 10-second base time.
Do I use lamp face irradiance or irradiance at the joint? Always the irradiance measured at the joint. Face ratings overstate what the adhesive sees after distance, angle and any window or substrate losses, which would make your cure time dangerously short.
Cure time vs cure dose, what is the difference? Dose (mJ/cm2) is the total energy the adhesive needs; cure time (seconds) is how long it takes to deliver that dose at your measured irradiance. Time equals dose divided by irradiance.

Last reviewed 2026-05-12.