Ep.7: Solder paste printing
On this week's episode we talk about something that at first glance might seem mundane, but is actually one of the most important steps and literally the foundation of pcb assembly: past printing. In fact, approximately 65% of all assembly defects come from this process. Chris breaks down all of the components that are a part of the often misunderstood process and provides some design tips on how to make it go smoother.
Show notes:
-Chris will be speaking at the upcoming virtual Altium Live conference. This year's event is free! https://www.altium.com/summit/
-We discuss what paste printing is and why it's so important.
Solder paste
-What is paste, what is it used for, and what are the different types of paste that can be used?
-Clean vs no clean paste
-Metal whiskering: https://en.wikipedia.org/wiki/Whisker_(metallurgy)
Jet printing vs stencil printing
-What is the difference between jet printing and stencil printing and what are the advantages and disadvantages of each?
Process
-What does the stencil printing process look like?
Stencils
-How are stencils made and what are they made of?
-http://www.stentech.com/Products/stencils
-https://www.youtube.com/watch?v=1gEcJvpinco
-https://nanoslic.com/nanoslic-coating-system/
Design tips:
-Use appropriately sized parts.
-Always avoid gang masking
-Tips to avoid via-in-pad issues
-Don't assume we'll use your data. Just leave it 1:1
-Be specific if you want paste on test points or battery contacts
-https://www.photostencil.com/technical-papers.php