Out on the line, potting failures don’t come with a warning siren. They show up as a tacky surface, hairline micro-cracks, and then the dreaded field returns. Most of the time, the culprit is an underperforming UV lamp, quietly slipping below the energy needed to fully cross-link the epoxy. A simple UV energy test strip makes that hidden drift visible—turning it into a number you can act on. What matters, technically For potting, you start with spectral match. A 365 nm peak gives you the deepest penetration into filled systems, while 385 nm and 405 nm can help top-cure without cooking the surface. Spec lamps by power density at the arc (W/cm²) and delivered irradiance at the work plane (mW/cm²), measured with a calibrated radiometer. Set your cure speed by dose: most potting resins need 1,000–3,000 mJ/cm² to fully cure. Peak irradiance is what determines how fast that dose stacks up. Stability matters as much as raw output—expect <3% drift over the lamp’s rated life, and make sure reflector reflectivity stays above 85% after aging. Mercury vapor lamps with dichroic coatings focus the output and cut IR heating; ozone-free quartz removes the need for extra ventilation. Here’s why this works in practice. A quick check with a UV energy strip gives you the delivered dose in seconds. If the strip isn’t hitting the required level, you adjust lamp height, confirm reflector alignment, or put a lamp replacement on the schedule—before you start piling up scrap. Consistent output keeps gel time under control, cuts rework, and keeps potting lines running at the cycle time they were designed for. A few shop-floor things to keep straight. Match the lamp to the cure window: too much IR and small boards warp; too little dose and the resin stays undercured. Output drops as the arc erodes, so plan replacements around the manufacturer’s rated hours—don’t just go by lamp color. Reflector cleanliness isn’t optional. Fingerprints and dust will rob you of irradiance. Make sure your radiometer matches the lamp spectrum, and confirm fixture compatibility so airflow and cooling stay consistent.