24 Feb 5 Things to Keep in Mind When Protecting With Parylene
Parylene offers the best protection against solvents of any conformal coating. It is also brings to the table excellent moisture and gas protection, very high dielectric strength, and is bio-compatible. Even with all of these benefits, there are still some disadvantages to using parylene versus other conformal coatings.
The cost for parylene is typically higher than other conformal coatings. While not necessarily true for all applications, this is due to the process, the raw materials, and the labor required to properly preparing a device for coating.
This means that there is a limited amount of space available in the chamber for every coating process. The goal is to maximize the amount of items to be coated in the chamber. Price per piece changes depending on size and space.
Raw material cost
Parylene dimer is expensive and is typically priced per pound. Because parylene is applied through a vapor deposition process everything gets coated. Masking can be a labor intensive in return which means more expensive.
High volume manufacturers run into the problem of time being spent in the parylene machine, which can take anywhere from eight to over twenty-four hours. Limited space means limited size for objects to be placed in the chamber and that means some larger orders will take more time.
Adhesion to metals
Parylene to consider is the poor adhesion to many metals such as gold, silver, stainless steel and other metals. While there are some adhesion promotion methods that will improve adhesion they are either material or labor heavy and can increase costs significantly.