Electronics Forum | Wed Oct 12 13:44:10 EDT 2016 | dekhead
Yes, bottom-side fids are usually half-etched with epoxy fill. just the half-etch gives a pretty "dirty" looking fid.
Electronics Forum | Wed Oct 12 11:02:59 EDT 2016 | hken
I think stencil manufacturers back fill half etched fiducials with black epoxy or something. I know I've had some worn and that's what I've done for my vision systems to be happy again.
Electronics Forum | Thu Oct 20 12:33:39 EDT 2016 | cyber_wolf
We get our fids laser etched and never have fid read problems. They are black. (see attached) All of our printers are Momentums. Half etch and fill is old school. I used to take 2 part epoxy and mix black printer toner into it and squeegee the mi
Electronics Forum | Wed Feb 07 13:43:33 EST 2007 | realchunks
Board vendors are always right. Unless you build yourself in their facility, at their price. Ways around this are half etch your stencil over the vias, open the resist (mask) on the vias, or use your own product (Sipad). The resist (mask) does app
Electronics Forum | Tue Jun 03 01:03:04 EDT 2008 | daxman
Hi, I think what you are describing is a half-etch QFN, which causes the 3 mil gap. In our process, we don't require solder to bridge this gap as it's internally connected to the bottom lead. I'm not sure if this is the question you're asking, but
Electronics Forum | Sun Oct 28 23:32:25 EST 2001 | flynhi34
Thanks for the info on the printers. I have printed conductive epoxy on Dek 265 with great success in the past. The issue I have is that I need to attach with both epoxy and solder on the same side of the PCB. I could double print. Print conductiv
Electronics Forum | Tue Jan 04 09:26:22 EST 2011 | scottp
We've been doing this for over 10 years using flux. We print a tacky flux first using an 0.002 or 0.003" thick stencil, then print paste using a thicker stencil with the underside half etched to keep it away from the flux. In our case, we can't jus
Electronics Forum | Mon Nov 12 16:14:47 EST 2001 | davef
Yes!!! How can we assemble boards with 20 pitch when we allow 0.008� error to the master art? Excellent question!!! IPC-D-300G has nothing to do with assembler requirements. It is written by and for fabricators, so that they can be comfortable.
Electronics Forum | Mon Jul 13 07:25:09 EDT 2009 | hcarrasco
Hi everybody, > We recently start to use an ultrasonic stencil cleaners for our stencils. > It' work well, but after some time, we saw a lot of fiducial that the black > epoxy have been partially or totaly remove. I want to know if someone h
Electronics Forum | Tue Jan 03 17:38:38 EST 2012 | davef
Here's two ideas fro the fine SMTnet Archives: * On the bare board, during design / layout, the basic shape of the jumper is a 125 thou disc of copper [that of course is eventually covered with whatever solderability preservative we use on the board]
