Electronics Forum | Thu Oct 12 11:08:20 EDT 2000 | Fraser
Dave, Why on earth would you want to use a stepped glue stencil?. If you print slightly off contact the hight of your glue deposition will be roughly half the width of your adhesive aperture width so if you want a 10mil high deposit use a 20 mil ape
Electronics Forum | Fri Oct 22 21:23:59 EDT 1999 | se
Tombstoning is usually oven profiling, see October 14 thread below. Aperture rules are misleading. Component mix, stencil thickness, paste factors, all contribute. Also, are you making the stencil from a paste or pad layer or from a soldermask layer?
Electronics Forum | Thu Mar 25 20:09:35 EDT 2021 | grahamcooper22
What is the QFP pitch ? What aperture dimensions have you chosen ? Is the stencil laser cut then polished ? Your AFTER stencil size looks promising...your BEFORE stencil aperture size looks disastrous...would surely give bridges.. Your pcb pad siz
Electronics Forum | Tue Nov 09 17:12:38 EST 1999 | Dave F
Steve: Addressing your points: 1 FINE PITCH APERTURES Electropolishing Laser Cut Stencils: Laser cut should not requiring polishing. Geesh, how much money do you have for stencils? ;-) Oval Shaped Apertures: Pass. What do you expect to gain f
Electronics Forum | Fri Sep 21 10:56:38 EDT 2001 | davef
Not as such. Look at IPC-7525 �Stencil Design Guidelines� The issues are: area and aspect ratios. They relate the size of the aperture opening to the thickness of the stencil. Check the fine SMTnet Archives for guidelines.
Electronics Forum | Tue Sep 07 09:11:33 EDT 1999 | Dave F
| We've noticed that there are many different recommendations for pad sizes for various SMT parts. This seems to vary wildly from manufacturer to manufacturer for the same case sizes. Is there any standards that can used used to specify these sizes
Electronics Forum | Fri Mar 03 09:48:06 EST 2000 | Wolfgang Busko
I have heard about it. The main reason is to save money. The problem is, or better is said, that the mixing isn�t that simple for you got have a homogen paste afterwards and the solderballs shouldn�t be deformed in size so that problems during printi
Electronics Forum | Fri Mar 03 09:48:06 EST 2000 | Wolfgang Busko
I have heard about it. The main reason is to save money. The problem is, or better is said, that the mixing isn�t that simple for you got have a homogen paste afterwards and the solderballs shouldn�t be deformed in size so that problems during printi
Electronics Forum | Fri Oct 13 13:44:03 EDT 2000 | Mike McMonagle
You can achieve a wide range of dot heights when stencil printing by using a polyimide stencil along with a .040 snapoff. Loctite has a system for this that they call Varidot, by varying the size of the apertures in combination with the .040 snapoff
Electronics Forum | Thu Mar 25 23:23:00 EDT 2021 | llawrence
The QFP pitch is 0.5mm. Pad size is 1.475 x 0.3mm, and the new aperture size is 1.32 x 0.22mm. I'm not sure about whether or not it is lasered, but on the newly ordered stencil I selected the polishing option. Looks like the pad width is already 2/3
