Lessons in Powder Coating: All Around, But Not Too Thick!
We sometimes receive requests that seem simple, but can be quite a challenge for us as powder coaters. An example of this is the complete coating of certain types of profiles, including all corners and gutters, without applying too thick a layer. Because if the powder coating is too thick, problems arise with fittings or parts that have to be mounted afterwards.
The technology behind powder coating in brief : Powder coating is an electrostatic process in which charged powder particles are applied to an object to be coated using hand spray guns and/or robot guns. The object to be coated is grounded, which gives it an opposite charge to the charged powder particles. This attracts the charged powder to the coated object.
The Faraday effect can cause corners, edges and deep recesses to not be covered properly. The electrostatic charge pulls the powder to the nearest points. This makes it harder for the powder to reach these places. In powder coating land, we also call them 'the hard-to-reach places' .
This is where our experienced powder coaters come in. They can accurately cover these areas by moving closer with a hand gun and working with a lower voltage. However, this also leads to the powder not only adhering to the hard-to-reach areas, but also around the profile, resulting in a higher layer thickness (and the so-called orange peel effect).
This brings us to the challenge of the request: 'round, but not too thick'.
By the way of hanging and the settings of the manual spraying, the boundaries of the possibilities are explored. Sometimes you find an area exactly on that boundary that the client is satisfied with, and then we can establish a method with which we can guarantee this quality.
We would like to conclude this article with some tips regarding the coat side:
Always clearly indicate which side of the object to be coated is the coating side.
If necessary, add what the primary and secondary coat side is.
If the object needs to be coated all around, consider a hanging method:
All-round coating is possible if the coated object has hanging holes.
In this case, indicate where the holes should be or make sure they are already there.
In case of more than one coating object: make sure that the holes are made at the same pitch. This allows the powder coater to hang the materials under each other and the traverse is filled optimally.
Longer objects are at risk of bending. Therefore, ensure that the holes are positioned so that the parts have sufficient support to minimise bending.
Profiles with open ends can be pushed up for all-round coating. Finally, when requesting 'all-round, but not too thick', please take the above explanation into account.
Finally, when requesting 'round, but not too thick', please take the above explanation into account.
Photos: @Sunshield, @SimXpro
If you have any questions or additions regarding this article, please feel free to share them below.