Electronics Forum | Thu Nov 03 14:23:58 EST 2005 | Samir Nagheenanajar
Thank you for the advice. I am not so concerned with the "2nd reflow", as the same can be said for double sided reflowed PCBA's (the bottom-side parts essentially go through a 2nd reflow). As for the HASL, there is a formula in calculating how much
Electronics Forum | Sat Nov 18 21:20:58 EST 2006 | Fer
Dave, May I ask where did you find the 1.5%, or the goal of .005" (or .007") per inch? The IPC-A-600 bow and twist standard calls for a .75% based on the calculation of the test method TM-650, method 2.4.22, which calculates the percentage based on
Electronics Forum | Tue Jul 24 08:44:17 EDT 2007 | rgduval
Ron, I'd agree that that sounds high. Some things that may be contributing to it: Volume. lower build quantity often leads to higher placement costs. NRE. Does this website quote an NRE for solder stencils, machine programming, and reflow profili
Electronics Forum | Tue Apr 27 16:00:19 EDT 2010 | scottp
In a nutshell, Cp is a measure of your process variation compared to your spec limits and Cpk is measure of both variation and how well your process is centered within your spec limits. Cp = (USL-LSL)/6*sigma where USL=upper spec limit LSL=lo
Electronics Forum | Thu Jun 24 14:32:59 EDT 2010 | remullis
Not sure what's in your line equipment wise, but you need to know relatively what kind of placements per day you run regardless of the mix. We run around 1.1 million across 5 lines in 3 shift. Calculate what kind of placement per day on a specific
Electronics Forum | Wed Feb 20 15:49:56 EST 2013 | markhoch
Actually, we calculate it BOTH ways, and track each of the two times. TOTAL changeover time starts when the last board of the previous run enters the oven and stops when the first board of the next board enters the oven. (Much the same way you would
Electronics Forum | Tue Apr 16 05:05:32 EDT 2013 | stivais
We recently had a discussion with customer's QM - he claims that calculations for a proper solder wire diameter and soldering iron tip size (and temperature) have to be performed and documented for all manual (T/H) solderings (based on component size
Electronics Forum | Mon Dec 03 15:03:49 EST 2018 | dleeper
I can't open your spread sheet to see how you calculate this, but usually this sort of calculation assumes the leads are spaced symmetrically on both sides of the part and the center of mass is between them. Gravity pulls the part down, while the wet
Electronics Forum | Thu Mar 21 16:50:10 EDT 2019 | emeto
Hello, I've done it before in Excel and it is a very simple concept. Inputs are board size, numbers of SMT and TH process sides, number of SMT and TH placements per side, boards per panel and quantity of boards to be produced. Output will be calcul
Electronics Forum | Thu Mar 02 15:12:50 EST 2000 | Robert Hartmann
To restate my question of earlier, if I have a .020" sphere before reflow, and my pad opening in the dielectric is .017", is there a rule of thumb to calculate the height of the sphere after reflow? We are using 62Sn/36Pb/2Ag spheres. This should h
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