Conformal Coating and Masking in DAVE Embedded Systems' products
DAVE Embedded Systems has a huge experience in coating and sealing of embedded systems for many applications: railways, transportation and military/avionics are the main areas where these features are required but also many industrial products requires to protect the electronics boards against:
- short circuits
- thin wiskers
DAVE Embedded Systems has developed its own internal quality procedures in according with the standards MIL 610 and 610D. In the following are described the main working phases with some hints about our internal quality procedure:
- Cleaning with co-solvent product (Washing)
- Masking area must be clear by coat
Before apply any sealing or coating it is important to clean the board even if a noclean paste is used. Typically we adopt a Co-solvent product like TOPKLEAN EL20-R. A
The main scope of Sealing is to preserve BGA by DUST or DIRTY that can cause failure on the field. Sealing product must be easily removed in case of service repair, since a peel mask product must be used. We adopt typically approved sealing material for military applications likeDYMAX 9-20318-F which requires UV Curing. With this material a good result is assured in automatic process with great repeatibility. In particular bubbles and void are easily solved with this kind of process and material.
After the sealing process it is possible to proceed with conformal coating process. Typically this process should require to protect some areas from coating application. For this reason masking is mandatory.
Masking operation is need to:
Preserve area required to be clear by coating
Mask mechanical holes to prevent that coat cross PCB to one side to other side during coating (coating defect issues can happen)
Masking operation can be performed with adhesive tape material on mechanical holes and on top of components and with other type of peel masking
The main scope of Coating is to preserve components from dirty and external agents (humidity, etc..) that can cause failure on the field. Coating product must be easily removed in case of service repair, since a peel mask product must be used Humiseal 1B73 with a variable thickness min 25um - max 75um