Osh Park Docs ~ Tips+Tricks ~ Understanding
Spot mask may be hand applied, distributed with a pneumatic system, or stencil printed. Each utility methodology has its own benefits, disadvantages, and challenges. There are many theories as to why inexperienced grew to become the default PCB color. No one appears to know for certain which is appropriate, possibly it's because of a mixture of things or something that nobody is aware of or remembers. Another cause for shade variation is that PCB factories will sometimes purchase mask materials from completely different suppliers because of cost or availability, the exact shade will differ from supplier to provider.
If that is the case, the masks will are inclined to clog the dispensing tip because the stress will increase. WonderMASK P peelable masks, or WonderMASK WSOL and WonderMASK W washable masks have excessive shear curing, so will keep away from this drawback. Pneumatic dishing out systems reduce the variability within the utility course of, and open up the possibility of automatic dispensing. When utilizing a pneumatic dishing out system, masks is pressurized with both compressed air or nitrogen and pushed by way of a allotting tip. For this type of utility methodology, clogged suggestions are the most important headache.
Otherwise it might create a cracked, ragged edge, and even pull up the coating. Natural latex is recommended, because synthetic masks can generally interact with harsh solvents used in conformal coating.
The solely disadvantage is that the white silkscreen does not have excessive contrast with the board, subsequently, most of the time, black silk printing is the higher alternative, even if generally it isn't passable. Techspray’s lab is on the market that can assist you qualify merchandise, establish your masking course of, or diagnose masking issues. Conformal coatings repel water, so a washable mask will be troublesome to take away from beneath the coating. Many masks have excessive shear-curing, which implies stress accelerates the curing process.
The bead of masks is thinner when holding the bottle at 90°. If you are spraying or dipping conformal coating, masks can be utilized to protect connectors and other areas that can’t be coated. If you prefer a extra lovely colour to match with the immersion gold floor, purple is worth a strive.