Electronics Forum | Fri Apr 23 16:19:17 EDT 1999 | Todd
We are just starting to manufacture a PCB with a .039" fine-line PBGA. We are currently seeing voids, mainly in the center, that are as much as 45%. We also intermittently see the corner balls of the PBGA smaller than the center balls. We are using a
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
Electronics Forum | Mon Apr 26 15:04:14 EDT 2004 | pjc
You are correct in understanding that the vision system comes into play for subsequent boards- to align them. Yes- if you missalign the first board and set the cameras to that board, all subsequet boards will not be aligned. Mylar is a thin polyester
Electronics Forum | Thu Nov 10 15:43:10 EST 2005 | 1st Article
myu, Is using a 0.6mm stencil wise? 42.5 X 42.5 has two models, the 1mm pitch has 41x41 array with 1657 I/O and the 1.27mm pitch has 33x33 with 1088 I/O. For a typical c-cga with 1.0mm - 1.27mm pitch, may requires a 2mil stencil, 1.0mm pitch gets .
Electronics Forum | Fri May 12 08:39:24 EDT 2000 | steve
We are a small volume pwb house and I am tring to convince the people here that we should purchase a stencil cleaner. Besides the obvious of cleaning all of the past out of the apertures what are other benefits of usings a cleaner of hand cleaning.
Electronics Forum | Tue Jun 05 16:40:46 EDT 2001 | kerryn
Thanks Phil. However, my objective is to identify stencils that are not 100% clean prior to sending to inventory. I want to catch it before the solder paste has a chance to dry and harden in the apertures. Kerry
Electronics Forum | Mon Jan 24 19:24:46 EST 2000 | Scott S. Snider
Every stencil supplier I have worked with had this type of information available in some format. I recommend contacting whoever you are purchasing stencils from and asking for the information. Scott Snider
Electronics Forum | Mon Feb 20 20:47:59 EST 2006 | davef
We assume your stencil is clean. So, try: * Reduce stencil separation speed. * Reduce squeegee pressure. If the pressure is not proper, excess number of particles are stuffed into an aperture and inner pressure / friction among particles increase, an
Electronics Forum | Wed May 19 16:35:18 EDT 2010 | stepheniii
How thick is the stencil? Also what type of paste? We have a nice little microscope that has gradients on the lens so we can measure whether an aperture is 8 thou or not. Almost always it is but then we buy from a couple of good stencil suppliers.
Electronics Forum | Wed Feb 28 08:04:53 EST 2018 | emeto
With saving time and space. With having the possibility to change any aperture at any time. With having the chance to apply different deposits on the same assembly or the same part. A stencil printer is not for free as well and it needs consumables t
