SMT Stencil Cleaning Series – What is the Best Way to Clean My Stencil?

Choosing a Stencil Cleaner Process.
–Barry Thomas

What is the best recommendation for the amount of time between stencil cleaning?
I hear that one often. It really depends on the complexity of the assembly and understanding the solder paste being used, the design itself, and even the printer settings. A good rule of thumb that I tell individuals is once you begin to experience non-repetitive results, this would be a good time to clean the stencil. I would say do it a little bit more frequently than less frequently.

Our company currently uses 3 different types of solder paste; do I need 3 different stencil cleaners?
Well, the short answer is no. Many companies, including KYZEN, manufacture multiple chemistries that are designed not only to clean solder paste but other adhesives and epoxies. The only thing I would say at this point is that make sure to caution yourself if you’re issuing IPA. It may not be the best solution especially if you’re running multiple pastes. It might be good for you to consider an engineer solution and we would be happy to help you with that.

How does cleaning a stencil help improve print yields?
That’s a really good question. It’s been noted that 65 percent, maybe 70 percent, of the issues start at the printer. It doesn’t really matter whether it’s 65 or 70, they’re both too high. What we need to do is make sure that the stencils are clean. That’s the biggest concern. Make sure you’re SMT stencil is structural sound and there is zero contamination within the apertures. If you do this, you’ll get a more consistent print and that will help reduce the chance of defects, misprints, and downtime.