Electronics Forum: aperture shape (Page 9 of 16)

Re: BGA SOLDER BALL to SURFACE PAD size relationship

Electronics Forum | Thu Feb 24 13:28:31 EST 2000 | Dave F

Robert: Ah, opinions are like mothers, everyone has one. Here's mine: 1 Goto the Altera site, get a copy of "AN 114," follow it. Generally, manufacturers are closer to the requirements of their components than others are. 2 Metal showing on the b

Re: Printing Adhesive

Electronics Forum | Wed May 05 23:26:29 EDT 1999 | Dean

| OK, my manager read an article on printing glue (aaargghh!)and wants to know why we aren't doing it. We currently use Fuji GLs and GDMs to dispense glue. I've never done it, but have seen it done at NEPCON and other shows. It looks OK, BUT what

Re: Clamshell printers

Electronics Forum | Fri Aug 04 15:45:27 EDT 2000 | John Thorup

Ditto to everything said. If everything in the process is correct you will have good success at 25 mil but it will take much care. I have done 20 mil on this type of printer but, as Steve says, I wouldn't want to on a daily basis. Those wipe-offs a

Re: Electropolishing Laser-Cut Stencils

Electronics Forum | Wed Jul 15 12:22:57 EDT 1998 | Steve Moore

Electropolishing definitely improves the print characteristics of both Laser-cut and Chem-etch stencils. The caveat here is avoid over polishing which results in rounding of the edges and/or enlargement of the openings. Over polishing is typically th

How important NSMD pads are for the QFN and similar packages?

Electronics Forum | Wed Jul 30 11:36:31 EDT 2014 | emeto

About the pads shape - you can do rectangular or oblong. For stencil design oblong is better for small pads(0.2mm) because it will give better release, so having this thought in mind you should probably design oblong shape and then print make paste a

Stencil Apertures

Electronics Forum | Sat Jul 01 04:22:09 EDT 2000 | Sal

I have two questions 1. How do I control the skewing of FETs/power regulators ? ( the one's with the big rectangular pad and two smaller one's for the leads).If I go 1:1 with the apertures I seem to get solder balling and when I tryed to minimise th

Re: paste release from stencil, and volume calculation

Electronics Forum | Sat Nov 13 14:09:45 EST 1999 | se

First, let me say what I always say: a good chem-etched stencil will print fine pitch. Chem-etch brings trap to the side walls because its a physical by-product of the process. Because they are less expensive you can add electropolish and still save

Re: polyimide stencils

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

Re: polyimide stencils

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.

Effective Alternatives To Stencil Cleaning

Electronics Forum | Wed Feb 21 16:14:44 EST 2001 | billschreiber

120 degrees F (49 degrees C.), check the fine-pitch apertures for shape distortion (stainless steel has a very poor memory, once it expands, it doesn�t always contract back to the same position). Check for dings and dents. A good stencil cleaning pr


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