January 13, 2016
Stencils are used extensively in the PCB industry for controlling the application of solder mask and solder paste.
A stencil can be produced by first coating it with photoresist, then using a file mask to expose the photo resist, develop it, remove the unexposed resist with a solvent and finally etching the stencil. One normally has to define a pattern on both sides (in registration) which doubles the work.
Some stencil manufacturers are now trying to define the etch patterns by the direct application of photoresist using an industrial inkjet printer thus avoiding the generation of a film mask, and the coating, exposing and developing, and removal of the un-hardened photo resist. But is this practical and economical?
We'll examine some of the issues. Of course, our point of view is related to data conversion primarily.