Electronics Forum: stencil (Page 220 of 541)

16 mil pitch QFPs / solder paste type 4 & 5?

Electronics Forum | Mon Apr 07 12:21:02 EDT 2003 | davef

Russ is correct. A 5 thou thick stencil should give good release. Here's how you run through it: * You want at least 5 solder particles across the smallest aperture. So in your case, 8 thou wide, which equals to 0.20mm gives us 0.20/5=40 microns.

Screen washing

Electronics Forum | Wed Aug 27 00:45:35 EDT 2003 | kenBliss

Bman Each area and process has a unique machine for a reason. Professional engineers at the various OEM�s have thought these things through and there are specific reasons why you don't wash stencils in a board washer, bake pizzas in your reflow ove

screen printer comparision

Electronics Forum | Mon Apr 19 15:27:05 EDT 2004 | pjc

The MicroFlex is not really new. Its the UltraPrint 100 re-engineered and improved. UltraPrint 100 / SMTech 100 has been around for many years. I don't believe the DEK 248 offers a Stencil Wiper option. I worked on MicroFlex machines. Vision system i

Stencil Tension

Electronics Forum | Mon Oct 25 21:19:06 EDT 2004 | davef

Q1: I thought we have a industry standard for this. A1: We're unaware of such a standard. IPC-7525 - Stencil Design Guidelines has a brief section on stencil inspection. We've talked about it previously on SMTnet. If you can't find it in the Archiv

Sudden paste release problem

Electronics Forum | Thu Feb 10 09:30:32 EST 2005 | cyber_wolf

I am curious as to why you are using Koki ? Why are you not using a main stream paste that is proven in the industry? Indium,Kester,Multicore,AIM.... It has been my experience that when you start having paste-releasing problems out of the blue, it

Sudden paste release problem

Electronics Forum | Fri Feb 11 00:22:05 EST 2005 | Grant

Hi, That's what I am thinking, and we might have a dirty stencils and cannot see the problem. We are going to get a magnifier, and check it out. I did not think the stencil could bur, but I didn't want to shoot the guys down when they had an idea on

QFN Packages

Electronics Forum | Sat Feb 26 20:44:46 EST 2005 | siverts

Some of the QFN's have/has? (sorry for the grammatics but I live in Sweden) a "ground pad" underneath the center of the body. Some of the manufactories have made a specification of how much solder fillet that needs to be covered on the center pad [f

Solder dust

Electronics Forum | Tue Mar 08 09:56:05 EST 2005 | caldon

Tim- You have two separate issues 1) Stencils and 2) wave. Stencils you can purchase a ultrasonic system that will remove the paste automatically or you can use stencil wipes to remove it manually. I would refrain from using towels and IPA as it dilu

DEK underscreen cleaning

Electronics Forum | Thu Apr 14 06:54:02 EDT 2005 | teera

hi! below are the item need to check: 1)top plate condition(under screen squeegee). 2)under screen clean contact position(with stencil) 3)make sure the thickness of wiper paper not so thick(not over 6o gm)becaue it will effect the vacuum suction. 4)s

Problems with .45 mil ball diameter BGA....

Electronics Forum | Wed Apr 27 02:22:08 EDT 2005 | grantp

Hi, There are a number of things you can try. You are already using 1:1 hole to pad ratio, and that's good as you need the size. I would try an electroform stencil as that will have a smooth side of the aperture and help paste release. Don't use c


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