Electronics Forum | Fri Apr 06 09:29:20 EDT 2018 | jacobidiego
Hi Experts, I am interested in having a tool or process to measure coplanarity between the PCB pushed-up in the printing process and the Stencil. Therefore having a way to calibrate them.
Electronics Forum | Mon Apr 09 11:39:32 EDT 2018 | emeto
The easiest way to do without special tools is to use level. Check machine co-planarity on the conveyor rails in both directions(you can do that with rails down or rails up or both). Then check co-planarity on the stencil. If the level shows the sam
Electronics Forum | Tue Apr 10 16:27:20 EDT 2018 | emeto
Of course, the more accurate the better. However, it might be a challenge to calibrate with really precise one - still better to take your time and do it right. Good luck!
Electronics Forum | Wed Apr 11 21:00:54 EDT 2018 | jacobidiego
What I mean is.... What Brand and Model should I buy to measure coplanarity between this 2 surfaces that could measure micrometers of difference I think that normal bubble levels are not precise enought for this use ^^
Electronics Forum | Mon Apr 09 11:31:36 EDT 2018 | emeto
I would still focus on the sensors first. Experiment and see if they are really registering correctly. Still might be a sensor malfunction, timing issue(enough time to register)or some actual debree on it that prevents it from changing state properly
Electronics Forum | Mon Apr 09 13:50:38 EDT 2018 | justconmac
Thank you, yes I am definitely going to go back through and clean them thoroughly and monitor them, especially at rack location.
Electronics Forum | Tue Apr 10 10:21:06 EDT 2018 | slthomas
Dave, that's a cool idea and sounds like something that would actually work. I'd be tempted to go with oversized pads to increase the holding force. Unfortunately as an EMS we would have to work that through the customer approval system and as usual
Electronics Forum | Tue Apr 10 10:33:08 EDT 2018 | davef
Oh, I just remembered the other thing that I wanted to mention ... Do the pads match the component leads?
Electronics Forum | Wed Apr 11 11:55:54 EDT 2018 | slthomas
Yes - every dimension that I measured on the gerbers checks out against datasheet. Presumably the parts match it as well....?
Electronics Forum | Mon Apr 16 16:24:20 EDT 2018 | slthomas
Amazingly enough, every one of these held fast where we placed them with a paste brick sized 1:1 with the thermal pad, no sectioning. Yes, there were voids, but we can live with that in this application.
