Electronics Forum | Thu Aug 06 12:16:52 EDT 1998 | Rin
| I'm currently running a double sided paste smt board loaded with 0603's, on the secondary side. Many of the 0603 devices tombstone during reflow if the parts are not perfectly centered on the pads. Is this caused by the .008 foil thickness? Has any
Electronics Forum | Tue Jul 27 07:18:44 EDT 2004 | Nippy
How does the HASL finish and stencil match ? I have seen ocasions on fine pitch devices where the HASL can protrude into the stencil aperture either pulling paste down on the snap off or completely blocking the aperture and getting no paste.
Electronics Forum | Sat Sep 26 14:07:09 EDT 2020 | davef
Print no paste on the tin-plated, [test???] pad. Experiment by putting Kapton tape over the stencil aperture for the tin platted pad. Re-assess your reflow profile, since the liquidus of the two plating materials will be different. Evaluate your pa
Electronics Forum | Wed Nov 18 18:10:16 EST 1998 | fraser
| | | | | | I keep hearing about polyimide stencils, but what are they like in terms of registration and aperture accuracy? | | | | | | | | | | | Fraser- | | | | | | | | | | We use polyimide stencils with great success for our prototype boards.
Electronics Forum | Fri Nov 13 14:43:36 EST 1998 | Dave F
| | | | I keep hearing about polyimide stencils, but what are they like in terms of registration and aperture accuracy? | | | | | | | Fraser- | | | | | | We use polyimide stencils with great success for our prototype boards. They are cheaper a
Electronics Forum | Wed Jul 03 07:29:05 EDT 2002 | jax
Where did you find this article about "U-shape" apertures? I believe it is simply talking about rounded corners on the inside of a normal square aperture. ( resembling a filled in U ). It kinda follows the same ideas behind the home-plate design, wit
Electronics Forum | Thu Jun 22 11:42:29 EDT 2000 | Chrys Shea
Sal, Silly question: Were the parts skewed before they went into the oven? I've chased down a few similar reflow problems in my lifetime, only to find out it was a pick and place problem. Wrong nozzle size, bad nozzle, feeder not advancing all
Electronics Forum | Sat May 27 12:50:21 EDT 2000 | Micah Newcomb
Steve, I use homebase apertures as a standard for all chip parts and have no complaints, no solder beading, no issues. I have had to replace almost all stencils ordered previous to my arrival as they all caused defects (7-9mil thickness and 1:1
Electronics Forum | Sun May 28 08:21:52 EDT 2000 | Sal
Can't agree more than moving over to Homebase apertures, But ensure that the cut back angle is correct,to acute of and angle will leave you with an inadequate contact area fot the terminations on the chip components and you will start seeing insuffic
Electronics Forum | Mon Nov 16 12:41:46 EST 1998 | MMurphy
| | | | | I keep hearing about polyimide stencils, but what are they like in terms of registration and aperture accuracy? | | | | | | | | | Fraser- | | | | | | | | We use polyimide stencils with great success for our prototype boards. They are
