powder coating

One of the main issues is to make sure your parts are clean...oil free, dirt free, etc. The best powder and application techniques won't work if someone tries to coat dirty parts.

Good luck! I am about to try by 6th powdercoating vendor. The first one I tried introduced me to just about every possible flaw available: non coverage, drips and sags, orange peel finnish, dirt in the paint, parts that were touched before baking, dropped and broken parts, out-gassing, and seepage through the paint because of parts not being cleaned well enough. They all seem to be able to powdercost black or white with only about a 10% failure rate. Red seems to be very difficult and yellow almost impossible.

You are asking about powder coating? That is using plastic powder that will be static charged to stick to the objected sprayed. That as already mentioned, the objects need to be clean with solvent, else you will have peeling (poor adhesion), pin-holes (oil) etc. Other parameters are coating thickness. Less than 25 micron, the surface are flat and thicker coat will result in orange peel which can be desirable if you do not want to reflect too much light. Up to 250 micron can be achieved although that is not desirable due to cracking. Generally, 120 micron is the max. One important parameter is baking temperature, this will ensure that the plastics (usually thermalsetting type) will be properly cured. Note that baking temperature is not the same oven temperature setting because the surface temperature of the object is usually lower than the oven temperature setting. Colour can also be affected by the baking temperature. Example for yellow powder, higher temperature, say 250 deg C, will make in more deeper yellow. Follow the recommended temperature on the supplier material safety data sheet and use a photocolour meter to check the colour against a master sample from the supplier. Adjust the temperature accordingly but not below 180 deg C. Temperature control is very important for ESD powder.