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Best practices for changeover --Leaded > Lead-free > Leaded--

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Best practices for changeover --Leaded > Lead-free > Leaded-- | 2 December, 2014

Hola, here is a question that may be answered by common sense, but I'd like to hear from you;

I have a couple of SMT lines, and I'm constantly changing from leaded to lead-free process and backwards, so, I cannot dedicate one line for leaded and another for lead free. What are the best practices to perform a changeover and avoid contamination?

PS.- my line consist in a solder paste printer, PnP, Oven, touch up station, hand insertion, hand soldering, visual inspection.


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Best practices for changeover --Leaded > Lead-free > Leaded-- | 16 December, 2014

The critical operations where cross contamination can occur is the paste printer, the touch up station and the hand soldering station. Hand insertion should not be a problem if the parts are kitted or issued with proper control.

If possible I would try to dedicate one through hole line as leaded and one lead free since those operations have the highest risk of cross contamination, and the two SMT lines can run either.

The key is to have a visual system. For example you could color code your lead free jobs green and your leaded jobs yellow. Imagine if your traver, router or job order would be printed on green or yellow paper. Then your solder and solder paste, soldering irons, etc. could be color coded too to match your job paperwork as the job moves through the shop. Then everybody should know what to use. Your totes could have colored tags and the workstations could have a placard with green on one side and yellow on the other so it could be flipped when you set up the line. Buy soldering irons with detachable wands so they can be easily interchanged.

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Reflow Oven

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