Paratronix Inc. - Parylene Conformal Coatings

A Design Guide for Parylene Coating

Electronics

Connectors:

Choose a sealed connector or back seal the connector before it is installed on the board.
Allow for space to work around connectors when they do require masking.
Card extractors and/or wedge clamps pose a masking problem and should be removed before coating.
Ejector latches are difficult to mask and can be bound up by the coating.
Male pin headers are preferred to female/socketed or shrouded headers.
Molded connector bodies are typically easier to mask than press fit.
Compliant pin connectors can be put on Backplanes after coating without the need to mask.
Consider putting long lead or ribbon cables on afterward if possible.
Power terminals and RTV filled terminals are examples of connectors that do not require masking.

Materials and Surfaces:

Try to use sealed components when adjustable items are needed (potentiometers, switches, etc.)
Select solder masks that will not have a deleterious effect on adhesion.
Clean board immediately after soldering operations to eliminate flux residues.
Allow for coating in areas where it is not required and will not hinder performance.
Some test points may not need to be masked or the masking can be left on and removed only if test is required.
Offer a wide tolerance on masking parameters when possible.

Metals, Plastics and Rubber

Surfaces need to be clean and free of cutting oils, mold release or other types of contaminants.
An etched or roughened surface usually will provide for better adhesion.
Impregnating or depositing an oxide layer on the surface can also enhance bondability.
Coating aluminum can sometimes perform as well as stainless steel and is easier to tool.
Parylene bonds very well to silicone rubber and neoprene. It is also used to coat other materials like plastic, glass and ceramic.

Please contact Paratronix to review your application
and discuss the options that are available to you.

Note: Paratronix maintains a staff of senior employees to handle the most difficult jobs. The above information is only intended to provide our customers with a base line to work from.

Est. 1981, celebrating 27 years of parylene coating service

Paratronix Inc., 129 Bank Street, Attleboro, MA 02703-1775.
508-222-8979 Fax: 508-222-8813 Info@Paratronix.com