Electronics Forum | Fri Apr 20 07:30:14 EDT 2001 | wbu
In short: the measured deviation / the length this deviation occurs * 100% = % of deviation Actually we encounter mostly "twist" so we put the board on a flat surface, hold it down at the corners to see if any of the corners lifts, measure the heig
Electronics Forum | Mon Apr 23 11:44:55 EDT 2001 | CAL
650 Standards are also located in the back of IPC JSTD-001. I am currently looking at 4 pages on bow and twist. Percent bow = R1-R2/L x 100 (R1= Highest point; R2=lowest or resting point; l= length) Percent twist=(R1-R2)/(2xL)x 100 Sorry if this is
Electronics Forum | Fri Apr 20 05:32:39 EDT 2001 | dougie
Hi, I've just splashed out �60 on IPC-A-600F trying to find out the formula for measuring the bow and twist of raw PCB's. Much to my dismay there are 10 lines on the subject in the whole standard. Worse still is that it tells me nothing I don't alre
Electronics Forum | Mon May 16 22:59:40 EDT 2005 | davef
We believe your problem is caused by the mismatch in CTE of the material ised in your BGA. In fact, this "potato chipping" [where the corners curl-up] is present in all BGA. The issue is the matter of degree. [Mismatching CTE is how old thermostats
Electronics Forum | Tue Oct 27 15:25:02 EST 1998 | Stefan W.
Hi Samson ! In order to give you more detailed information I would like to know what your component range is and how many boards you supposed to do. Panasonic and MPM are a good choice, however, Panasonic has not many P&P machines on the U.S. market,
Electronics Forum | Thu Aug 22 22:19:13 EDT 2019 | sssamw
From the picture you present, it is a pin in paste part with pin length 2.2mm (a good length for 1.6mm PCB thickness), and seems the pin tilted and touch on PCB surface, thus causes up-part. Sorry I cannot image pin tilted not before placement but i
Electronics Forum | Thu Aug 22 23:09:34 EDT 2019 | sssamw
Yes, you need work with supplier to see if can run pin in paste for these connectors, even do some experiments. A step-up stencil would be good for these connectors, also connectors pin size and length match with PCB hole design.
Electronics Forum | Tue Mar 07 21:35:16 EST 2006 | Cal Kolokoy
Samir, From experience, the only board test situation where tented via's have difficulty with contact is with a Flying Probe type tester. Otherwise, for traditional ICT, the force of the pogo pins, correct probe type, and fixture design should do th
Electronics Forum | Mon Dec 17 11:55:08 EST 2007 | chef
I recently had the same problems, solder bridges on every thing I made, different customers boards, etc. I wave with no-clean flux. As I sorted out problems (pin holes, blow holes, splatter, etc.) I found a lot of variable factors. I changed flux,
Electronics Forum | Wed Aug 10 02:38:36 EDT 2016 | zxcvb
I guess I've been somewhat ignorant when it comes to the finer details of pcb layout. Lately I've read a couple of books that try their best to lead me on the straight and narrow. Here is a couple of examples of a recent board of mine, and I have hig
