|
Sponsor
|
|
Eliminate Worry of Cross Contamination
While Models 529 and 1550 are similar semi-automatic cleaners with single wash and rinse tanks, the Model 2003 includes 2 wash tanks for cleaning multiple applications in one machine.
Smart Sonic
|
|
|
Sponsor
|
|
Start Micro Dispensing Today
The DL Micro Valve is specifically designed for dispensing micro volumes of material in precise, repeatable patterns. Learn more about the DL Micro Valve.
DL Technology
|
|
| Ask the Experts |
|
QUESTIONS
SUBMIT
MEMBERS
JOIN
|
August 15, 2011 - Updated
August 15, 2011 - Originally Posted
Stepped Stencil Limit
I've used stencils with 1 and 2 mil steps successfully, but recently I've seen a problem with a 3 mil step (8 mil foil stepped down over most of the printed area to a 5 mil thickness). The problem I'm seeing is that the stencil tends to warp around apertures, particularly in areas like fine pitch QFPs, where there are long apertures close together, and the remaining material is a thin strip. This warp makes the stencil act thicker and allow more paste to be deposited, leading to bridges in the fine pitch QFPs. Is there a rule of thumb regarding the amount of step that can be etched into a stencil?
B. B.
|
| Expert Panel Responses |
IPC 7525 recommends 35 to 50 mils keep-out for each 1 mil of step.
Bill Coleman
Vice President Technology, Photo Stencil
For over 18 years, Dr. Coleman has been the vice president of technology for Photo Stencil, working closely with customers to understand their printing requirements. His efforts have resulted in several new stencil products.
|
|
|
Free Newsletter Subscription
Circuitnet is built for professionals who bear the responsibility of looking ahead, imagining the future, and preparing for it.
Insert Your Email Address
|
|
Sponsor
|
|
Your Domestic PCB Solution
Summit helps you avoid long lead times and added costs—protecting your supply chain without compromise, while delivering the speed and quality you count on.
Summit Interconnect
|
|
|
