Double Print Stencils Systems
It is useful in Assemblies that require mixed technologies; including SMT / Through Hole, SMT / Glue attach components, Packages requiring die attach / SMT assembly.
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Authored By:
William E. Coleman
Photo Stencil
Colorado Springs, CO
Summary
The Two print stencils process has been a very useful tool in SMT Assembly and Package Assembly. It is also useful in Assemblies that require mixed technologies; including SMT / Through Hole, SMT / Glue attach components, Packages requiring die attach / SMT assembly. The concept is to print with a first print stencil which is thinner than the second print stencil.
The second print stencil has relief pockets formed anywhere that the first stencil printed. It is useful for several applications:
Printing Solder Paste for Through-Hole and SMT
Printing Glue and Solder Paste
Printing Flux and Solder Paste
Printing Solder Paste for SMT and RF Shields
Printing Reservoir Solder Paste for multi-level boards
Printing Solder Paste and Reservoir Flux
Conclusions
The Two Print Stencil System has demonstrated an effective printing process for Surface Mount Assembly Including:
Through Hole / SMT Assembly
SMT / Flip Chip Assembly
FR Shield / SMT Assembly
SMT / Glue Chip Component Assembly
Multi-Level SMT Assembly
01005 / Die Attach Assembly
Other applications not mentioned in this paper including printing lead free and tin lead on the same PCB.
Initially Published in the IPC Proceedings
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