Electronics Forum | Fri Mar 12 13:30:06 EST 1999 | Bill Schreiber
Dear Scott, You are correct in questioning the chemistry portion of the process. However, I am couriuous as to why you selected DEK as a stencil cleaner. The most important part of any cleaning process is always the chemistry. How you deliver the c
Electronics Forum | Fri Mar 12 13:40:53 EST 1999 | Bill schreiber
In a nutshell, you should be looking for a chemistry first, then look for a machine. Hopefully, they will be from the same source. | Dear Scott, | You are correct in questioning the chemistry portion of the process. However, I am couriuous as to w
Electronics Forum | Tue Mar 21 02:15:26 EST 2006 | pavel_murtishev
Good morning Dave, Here are some of my assumptions. Please correct me if I am wrong. 1. Mask opening. Due to mask to PCB misregistration mask is not always centered relative to pad center how is should be. Sometimes edge of the mask matches with ed
Electronics Forum | Tue Sep 21 13:17:29 EDT 1999 | Dave F
snip | I've often been tempted to try something a little different when specifying QFP apertures. Like, for example, using long, tapered triangular apertures arranged in alternating directions. The objective being, get the maximum amount of paste do
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 | Thu Jan 02 10:31:48 EST 2020 | slthomas
It is strange that you're having issues while using the same process parameters (including stencil) that worked successfully before. It doesn't guarantee that it's not one of those parameters changing in a manner that's not apparent, but it does sugg
Electronics Forum | Fri Feb 24 08:29:25 EST 2006 | davef
Step stencils are not widely used, due to: * Higher cost as compared to uniform thickness stencils * Danger of solder paste smearing at least close to the steps * Difficulty of cleaning the stepped stencil underside (the steps cannot be on the upper
Electronics Forum | Mon Aug 14 13:48:03 EDT 2023 | spoiltforchoice
Well gasketing yes, have you dine enough analysis to blame aperture design- Maybe not? Maybe whip out the gerber files for this PCB&stencil and compare the details with one you feel works well. Is there something different about their layout rules o
Electronics Forum | Tue Apr 01 11:18:47 EST 2003 | cyber_wolf
Is anyone out there successfully screen-printing SMD adhesive on an 0402 layout? We have successfully done 0603 and larger, but the deposition consistency on the 0402's is just not there. We don't always get enough epoxy on the board. We have tried a
Electronics Forum | Sat Nov 14 08:58:38 EST 1998 | Earl Moon
| I keep hearing about polyimide stencils, but what are they like in terms of registration and aperture accuracy? | You are hearing about polyimide as in polyimide film as Kapton (TM Dupont). This material is the stuff of flex and rigid/flex circuit
