When a manufactured part is powder coated there may be certain
areas of the surface that must be free of coating. For example, threaded areas may not fit properly if they are coated.
Bearing surfaces with close tolerance cannot be coated. Some parts may require a bare spot for electrical-grounding contact. It is important to select a mask that is effective, easy to use and reasonable in cost.
Masking parts will add additional labor to the coating process. It is
important to understand the different types of masking products that can be used.
Masking can be as simple as placing a plug in a single hole or it may
require a specially made mask or fixture. One large hole in a large
part will require very little labor while some smaller parts may have
numerous spots that need masking and require a lot of labor.
Selection of the right masking procedure will affect the cost of the
part.
The mask must be reasonable in cost and it must do an effective job of
keeping the coating off the masked surface.
There are many commercially available masking materials for and
powder coated parts. Tapes, plugs, caps and steel fixtures can be
used. These cost and benefit issues are considered to determine the
best possible way to mask a part:
- the cost per mask
- the number of times it can be reused
- the effectiveness of the mask
- the ease of application and removal
- ability to leave a clean parting line between the mask edge and the coating
- the need to be stripped and the frequency
- the temperature resistance of the mask material
- the ease of removal of adhesive backing
Summary:
Masking is a very important step in the coating process. It is labor
intensive and expensive. The type of masking material and its properties will be important to the effectiveness of the mask and its impact on production efficiency.
Keep in mind that any mask that is used must be efficient to apply and
remove, it must be effective at keeping the coating from the target
surface, it must stand up to the rigors of the process, and it must be
cost effective.
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