Troubleshooting the Stencil Printing Process - SMTA

More documents

Recommendations

Info

GasketingPoor AlignmentPWB ShrinkAperture largerthan padPad smallerthan aperturePaste on bottomof stencilSolder Mask on Mask padonPadHASL DomeN O T T O S C A L E
Stencil SeparationIf printer has stepper motor on Z-axis, separation speed isvery important to print quality:• Steppers induce vibration in the system, which causes pastes tothin out at aperture walls• Some pastes benefit by the localized shear thinning and workbest with slow separation speed• Some pastes thin too much with slow separation, producingpoor print definition and stringy bridges, and work best with fastseparation speed.How does the engineer know? Simple experiment.N O T T O S C A L E
Page 1 and 2: Troubleshooting the StencilPrinting
Page 3 and 4: Solder Paste Properties• Solder p
Page 5 and 6: PWBPads: Flat, RightSize, Free of D
Page 7 and 8: Solder PasteFormulation, Rheology,
Page 9: A Good Mechanical Setup isEssential
Page 13 and 14: Results16-mil pitch QFP
Page 15 and 16: Preventing The Bad and The Uglywith
Page 17 and 18: PSI and Solder Paste“Chops” eac
Page 19 and 20: Process ControlWith Automatic Solde
Page 21 and 22: Still Making Defects?Check the easi
Page 23 and 24: Check the ToolingNext: Remove the s
Page 25 and 26: Didn’t find the Root Cause?Time t
Page 27 and 28: Solder Bridges
Page 29 and 30: Poor Print DefinitionPeaks and “D
Page 31 and 32: InsufficientsPoor Aperture FillBonu
Page 33 and 34: InsufficientsPoor Aperture Release
Page 35 and 36: Poor Gasketing
Page 37 and 38: Poor Alignment
Page 39 and 40: Summary - Troubleshooting• Unders
Page 41: Questions?Contact Chrys at:chrys@sh

Troubleshooting the Stencil Printing Process - SMTA

Create successful ePaper yourself

Delete template?

Save as template?