Guide to UV Measurement
What can I measure, monitor, document or control on my UV System to establish process control?
For those who realize that they need to establish process control, the thinking usually follows this pattern:
“If I want to establish control of my UV system, I need to measure UV. To measure UV I need a UV radiometer. Therefore if I buy a radiometer, I will gain control of my UV process”
While measuring UV and the UV radiometer are an important part of the process, it is only part of the picture. Buying a UV radiometer and making UV measurements without testing and documentation will not lead to process control. Waiting for your coating supplier to take a reading with their UV radiometer every two-three months or having one sit in a locked cabinet in the production manager's office will not establish process control. Waiting until you have a curing problem instead of trying to establish control when things are working is not process control - it is process (and sometimes job) suicide. Talking the “joules and watts talk” will not give you process control unless you also “walk the walk” and understand what the radiometer ‘numbers' along with several other variables mean to your individual system and process.
To establish process control, there are several variables that you need to monitor, maintain and document in addition to ‘watts' and ‘joules'. Some of the variables have ‘numbers' that can be attached to their values, while others require confirmation that they have not changed over time for a particular set-up.
In your process and system you should evaluate which of the following variables in this section need to be monitored. You should also establish the frequency of measurement , and who is going to be responsible to monitor, maintain and track the variables over time. Often a log (example) can be set up for each system to track performance over time.