Requirements for PCB Conformal Coating
PCB Conformal Coating Requirements
1.Coating thickness: coating film thickness is controlled within 0.05mm-0.15mm, while dry film thickness is 25um-40um;
2.Secondary coating: in order to ensure the thickness of the product required for high protection, the secondary coating can be applied after the coating is cured;
3.Check and repair: visual inspection if coated circuit boards meet the quality requirements, and repair it if there is a problem.
4.Component replacement: after curing the film, if you want to replace the component device, do according to the following operation:
i.Use electric chrome iron to weld the components directly, and then use a cloth dipped in water to clean the material around the pads;
ii.Components replaced by welding;
iii.Use solid brush dipped in conformal coating to brush soldering components, and make the film dry and cured.
1.Conformal coating workplace should be clean and dust-free, be sure to have good ventilation and only staff can access;
2.When operating, wear masks or gas masks, rubber gloves, chemical protective glasses and other protective equipment to protect body;
3.After work is done, it is necessary to promptly clean used tools, and close containers with conformal coating;
4.Anti-static measures should be done on the circuit board, the circuit board can not be placed overlay, the circuit board to be placed horizontally during the coating process.
1.No flow paint, drip phenomenon on PCB board surface;
2.Conformal coating layer should be smooth, bright, thin and uniform. The pads, SMD components or conductor surface are all well-protected;
3.Coating surface and components can not have bubbles, pinholes, ripples, shrinkage, dust, powder, peeling phenomenon, etc;
4.Partially isolated elements or areas can not be coated with conformal coating;
5.Conventional non-conformal coating on these components and devices: high-power radiators, heat sinks, power resistances, high power diodes, cement resistances, DIP switches, potentiometers (adjustable resistance), buzzers, battery holders, fuse holders, IC blocks, relays and other types of sockets, pin headers, terminal blocks and DB9, plug-in or SMD LEDs (not indicated), digital tubes, and ground screw holes.