CyberOptics SE505, Hardware Manual

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CyberOptics Corporation 165
Solder Paste Failure Causes
Low Volume
Lack of paste in printer Look for patterns in low areas
Print speed too fast or pressure too low Look for paste left behind on top of stencil
Bad stencil design Look for apetures that will not stay clean
Wrong paste for stencil Evidence is small apetures won't print or stay
plugged
Plugged aperture on stencil Look for repeated issue on same pad on
multiple boards
Print pressure too high causing scooping Look at shape, if center is lower with no dog-
ears, then pressure too high
Dirty stencil causing poor release Jagged edges, poorly defined print
Old paste Paste clumps, will not move smoothly
Low Height
Lack of paste in printer Look for patterns in low areas
Print speed too fast or pressure too low Look for paste left behind on top of stencil
Bad stencil design Look for apetures that will not stay clean
Wrong paste for stencil Small apetures won't print or stay plugged
Plugged aperture on stencil Look for repeated issue on same pad on
multiple boards
Print pressure too high causing scooping Look at shape, if center is lower with no dog-
ears, then pressure too high
Dirty stencil causing poor release Jagged edges, poorly defined print
Old paste Paste clumps, will not move smoothly
Smeared paste Look for evidence that board was hit
Low Volume,
High Height
Dirty Stencil causing poor release Jagged edges, poorly defined print
Stencil aperture ratio poor Look for apetures that will not stay clean
Wrong paste for application Evidence is small apetures won't print or stay
plugged
Print speed too fast/Pressure too low Look for paste left behind on top of stencil
Board contamination inhibiting paste sticking to
board Paste appears to lift up all around
High Height,
High Volume
Board or stencil contamination preventing proper
contact Look for localized area of high volume/height
Foreign material Look for fiberglass/other material on board
Damaged stencil Dings in stencil of broken areas.
Poor setup preventing proper stencil contact
while printing Tap on stencil with board in position, stencil
should be very close.
Board support while printing Board flexes while pressed on when locked in
print position
Damaged Squeegees Check blades for damage - usually results in
line of defects, front to back.
Failure
Mode Possible Cause Evidence