This blog post outlines the techniques required for the removal of HumiSeal UV cure conformal coating. The products covered in this article are:
- UV40, UV40-250
- UV50LV
- UV500, UV500LV
There are 3 methods for the removal of HumiSeal UV conformal coatings:
- Mechanical removal: Powder Micro Abrasion
- Thermal removal: Burn Through
- Chemical removal
All three methods will effectively remove the coating, depending on the process requirements, to allow individual component replacement and subsequent re-coating.
Watch how Micro Abrasion System works
How To Remove All HumiSeal UV Cure Products
1- Mechanical Removal: (Powder Abrasion Method)
A powder abrasion system will safely and selectively remove HumiSeal UV cure conformal coatings from various components on printed circuit boards without causing any mechanical or ESD damage. The HumiSeal powder abrasion system is fully equipped with adjustable powder flow control and air pressure regulation to enable removal of the coating from pinpoint areas to larger areas. This method requires some relative dexterity as it uses high velocity particles delivered through a nozzle.
Watch how Powder Abrasion System works
2- Thermal Removal (Burn Through Method):
De-soldering techniques can be used to burn through or degrade a conformal coating. The temperature of the soldering iron decomposes the coating into a powdery solid that is easily removed from the substrate. This allows access to the underlying solder connections for component removal and replacement.
Procedure:
The temperature of the soldering tip needs to be at least at 450C. Place the tip next to the areas that need to be reworked and touch the tip on the coating surface. As HumiSeal UV coatings have excellent high temperature stability, the high temperature of the tip will only melt the coating into white solid powder rather than actually burn it.
Image #1 HumiSeal UV coating removed around a solder joint by thermal displacement
Although fumes generated by HumiSeal UV coatings have been proven not to be harmful, adequate ventilation is recommended to dissipate any fumes generated during this process.
Image #2 UV coating removed around solder joints after excessive exposure with the solder tip.
3- Chemical Removal Method
HumiSeal UV conformal coatings can be removed using select strippers after UV cure, before the secondary moisture mechanism has completed. See Table 1 for the appropriate stripper selection.
HumiSeal UV40, UV50LV and UV40-250 can only be removed using Stripper 1100 once the coating has been UV and moisture cured.
HumiSeal UV50, UV500 and UV500LV can be removed with the correct HumiSeal chemical stripper. Recommended strippers are, HumiSeal 1080A, 1090 and 1100.
If you have additional questions, don't hesitate contacting our HumiSeal Team.
