Hi all, We're starting up tests for pin-to-paste and, well, things could be better. We're testing different pastes and we're testing different apertures rules and, well, we're still testing. It's coming close and we're getting pretty good joint now, but we've got to slow down our chipshooter so that our paste doesn't go flying out every which way. Has anyone been through this phase before? Is there a solution for this or are we the only ones with this problem? Thank you, Hon -----------------------------------------------------------------
Hon,
What thickness stencil are you using? If you've got paste flying around the board, it sounds like there's too much paste on there. Pin-to-paste (Intrusive Reflow, Pin-in-hole Reflow, and any other names you can think up for it) is all about striking the right balance between getting good thru-hole joints without compromising the quality of the surface mount stuff. We've gone for a marginal increase in stencil thickness (0.008" instead of 0.006"), increased aperture sizes for the through hole items, reduced apertures for the SMT pads. We're also trying a different squeegee angle (45� instead of 60�) to push more paste down into the holes for the thru-hole components.
Bob Willis has done some excellent stuff on Intrusive Reflow. I'm sure he'll be posting a reply to your question too.
Good Luck, keep us informed about how you get on with solving this problem.
Scott
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