Ask Rob About High Aspect Ratio Boards

Hey Rob, my tin stripper works great most of the time. However, when I run high aspect ratio boards greater than 8:1, I am seeing tin in the hole. What’s wrong?

In an effort to reduce overall operating cost for the tin stripper, my shops set their specific gravity controller to cycle on and off at a Specific Gravity (SG) of 1.355. This is great for reducing cost and maximizing loading, but the higher SG is also what is contributing to the residual tin left behind on panels with a high aspect ratio. As the SG is increased, the density of the material rises, thus making the solution more viscous. The more viscous the solution, the more difficult it is to flow through small holes.

To avoid residual tin left behind, run the panels at a lower SG setting.