Electronics Forum | Fri Mar 09 15:10:08 EST 2007 | oldsmtdude
Simple question... Not so simple answer. It depends largely on process spec and honesty of the people running the test. Most will jump to throw out the flyers as "special cause". So if you didn't set the spec and didn't witness the run and measu
Electronics Forum | Wed Jul 04 12:22:07 EDT 2001 | davef
Several points: * Consider that your Cpk is probably different for both placing large and small components. * Probably your routine placement rate SB the speed you use to monitor the accuracy of your process. * Some people use a calibrated glass test
Electronics Forum | Mon Mar 03 09:16:09 EST 2003 | msivigny
Hello martys, The critical variables to measure print process capability on any printer are its ability to securely clamp a board, accurately align the board to its mating stencil, print with appropriate squeegee pressure and follow print material gu
Electronics Forum | Mon Dec 06 13:54:01 EST 1999 | Andy Yates
Mathematically, measure the component offsets from nominal then calculate the average and the SD of the offsets in x and y. You can then use the following equation to calculate the CpK: CpK = (Process Width - Abs(Average offset)) / (3 * SD offset)
Electronics Forum | Wed Jan 08 17:46:34 EST 2003 | ricardof
I would like to know how to implement CPk study on SMT line At this time we have the application to calculate CPk on Chip Placers for X and Y axes repeatability, but I'm trying to find what should I calculate on my Oven and paste printer in a simple
Electronics Forum | Sat Feb 10 09:36:52 EST 2007 | davef
Choices are: * Run a Cp, Cpk capable profiler through the oven. * Review the results of your supplier's process qualification that would include Cp, Cpk on their oven. Handspring contract [REV. 6 - 7/1/99] with Flextronics says: [snip] 4. Process Ca
Electronics Forum | Fri Aug 15 10:23:56 EDT 2008 | ck_the_flip
Ovens, and any other process for that matter, will ALWAYS vary. It's called process variation. I do Cpk (process capability) on my ovens. I track time-above-liquidus and peak temperatures. Statistics will validate how repeatable your oven is.
Electronics Forum | Sun Mar 09 19:03:48 EST 2003 | Dean
For the reflow process check out KIC THERMAL at kicthermal.com. They make a product called 24/7 which can collects data for process capability. I beta tested the unit about 2 years ago....interesting stuff.
Electronics Forum | Mon Feb 12 15:32:10 EST 2007 | davef
stepheniii Unsure how they determine that the process is stable and in control, a prerequisite to calculating Cp, Cpk. A trained chimp smoking a cigar could calculate Cp, Cpk.
Electronics Forum | Sat Nov 22 08:07:57 EST 2003 | davef
Search the fine SMTnet Archives for discussion on: * Machine capability * Process capability * Capability index * Cp * Cpk
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