Measuring UV Intensity & Dose with a Radiometer
A UV process you can’t measure is a UV process you can’t control. A radiometer turns "it looks cured" into a number, so you catch an aging lamp before it drops you out of spec, balance a splitter’s legs, and reproduce the same dose next month.
Cure depends on dose, and dose depends on intensity that silently drifts: lamps dim over life, guides lose transmission, splitter legs fall out of balance. A radiometer reads the intensity actually arriving at the working plane, so every one of those drifts becomes visible and correctable instead of showing up as a field failure.
A radiometer is source-agnostic bench equipment, it measures whatever you point it at. The UV0567 reads UVA intensity to 19.99 W/cm², covering spot-curing sources including the SunSpot 2.
Step by Step
- 1 Baseline a known-good setup. With a fresh lamp and guide, record the intensity at your working distance. This number is your reference.
- 2 Set the dose recipe. From the adhesive’s target dose (mJ/cm²) and your measured intensity, calculate the exposure time. Dose is intensity times time.
- 3 Re-check on a schedule. Measure periodically. A reading well below baseline flags an aging lamp or a lossy guide before it causes rejects.
- 4 Balance splitter legs. For a two- or four-pole guide, measure each leg and confirm outputs are within about ten percent so every joint gets a comparable dose.
- 5 Match the meter to the source. Use a radiometer whose spectral response covers your source’s output band, and read at the actual working plane, not against the guide tip.
Common Pitfalls
- Judging cure by eye, a skinned surface hides an under-dosed joint; measure it.
- Never re-checking, lamp and guide output drift downward; a scheduled reading catches it early.
- Using a meter whose response doesn’t match the source band, the number won’t mean what you think.
Questions
Why do I need a radiometer for UV curing?
Because intensity drifts invisibly, lamps dim, guides lose transmission, splitter legs fall out of balance. A radiometer reads the real intensity at the working plane so you catch those drifts before they cause field failures and can reproduce the same dose over time.
How do I calculate UV cure dose?
Dose equals intensity times time. Measure intensity at the working plane with a radiometer, take the target dose (mJ/cm²) from the adhesive datasheet, and divide to get the exposure time. If intensity drops, time must rise to hold the same dose.
How do I balance the legs of a splitter light guide?
Measure each leg with a radiometer and adjust per the guide’s procedure until the legs are within about ten percent of each other, so every joint cured on the splitter sees a comparable dose.
