What could be causing a bad UV cure?


Posted by Natasha Wallace on November 27, 2019

If you’re starting to find that your print results are not up to scratch or you are not getting the cure you would usually expect from your UV lamp, there are several things that Alpha-Cure would advise you to check before you replace your lamp. It is possible that your lamp will have just run the course of its lifetime, but if your UV system stops curing, it could be caused by some other common issues. Here are a few things to check before ordering your next lamp:

Reflectors

  • Are your reflectors dirty?
  • You will know if they are dirty because they will look cloudy.
  • We advise that all reflectors are cleaned regularly as they can reflect up to 70% of the UV light from your lamp, giving your system a huge advantage when it comes to curing. You can clean your reflectors with isopropanol wipes to keep them effective for longer.

Heat

  • Is your system running too hot?
  • A key way to find this out is if your lamp shows signs of clouding or white spots.
  • To solve this, ensure you are running the lamp at the correct volts and amps and that there is adequate cooling of your UV system. If heat is an issue and you replace the lamp without checking the system, the same thing will happen to the next lamp, so it really is worth looking at.

Overcooling

  • Is your lamp being over-cooled?
  • You will be able to determine this if your lamp has a mirrored effect.
  • Your system could be producing too much cool air that isn’t being circulated properly. Remember to keep your lamp shoulder temperature above 600C and ensure your lamp is being run at the correct power over prolonged periods of time.

Contaminated Airflow

  • Is the airflow in your cooling system contaminated?
  • This could be the issue if you can see devitrification occurring in your lamp. This is the process of the quartz turning back to crystal, so your lamp could look cloudy or opaque in places which stops the UV light transmission.
  • To correct this, ensure the compressed air is suitably clean and dry.

Inks, Coatings and Adhesives.

  • Is your print quality poor or not leaving the finish you expect?
  • When UV Inks, coatings and adhesives are not properly mixed, this can lead to poor curing results.
  • To ensure a good cure, all inks, coatings and adhesives need to be mixed thoroughly so the photoinitiator is dispersed evenly which will give you a better finish.

Position of Lamp and Humidity

  • If a lamp is too close to any metal work or the humidity is high, an earth fault occurs as the arc jumps to ground.
  • You may recognise this problem if you find that your lamp trips out often.
  • Ensure your lamp is correctly positioned. Check the reflectors are not distorted or too close to the lamp body. If humidity is high, consider getting a dehumidifier.



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