Raw Materials – Parylene Dimer and Adhesion Promotion
Parylene dimer is the raw form of parylene. It is the solid inserted into the machine that is broken down through the deposition process. Cost for parylene dimer can be anywhere from $200 to $5,000 per pound depending on the different type of dimer. A typical coating run is around a pound of dimer.
Different adhesion promotion methods require different raw materials. From various board cleaning solutions to A-174 silane, these raw material costs need to be added to the price per assembly. There is not much that can be done with these costs, as adhesion is the name of the game in parylene.
Parylene Labor Costs
Like all conformal coatings, masking is usually the most labor intensive part of the process. However, parylene is different from other conformal coatings in that it is applied in a gaseous state through a vapor deposition process. The parylene molecules will penetrate anywhere that air can. As a result, great care needs to be taken during the masking process to ensure that every connector is adequately sealed and all tape is firmly pressed against the coating keep-out areas.
Another factor that will result in increased labor costs is the increased time spent per board to increase parylene adhesion. Spending extra time cleaning products and applying different adhesion promotion mediums will result in increased labor times.
Parylene Lot Volumes
Items to be parylene coated are placed into a vacuum chamber. There is finite space available in the chamber and everything inside gets coated. In order to get the lowest cost, we have to maximize the products in the chamber. If we are able to divide the material costs among a greater number of boards, the cost per board drastically drops.