Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Damaged/dislodged components when doing second side of double sided reflow

Lee Radney

#4208

Damaged/dislodged components when doing second side of double sided reflow | 8 May, 2000

Ok... Anybody got any quick, low cost ideas that can help me here?

We run various panel layouts (all products are same width) thru our reflow oven. The problem is that due to the different layouts of our panels, the moveable center support chain has to be located in various places. A large majority of our product can run with the support chain exactly in the center. When a product does come along that the chain needs to be relocated due to the location of the bottomside parts, the operators forget - FREQUENTLY!! The parts get dislodged or in our last case (which had nothing but 0805 LED's) the parts get broken by the chain. We are racking our brains to come up with something that can remind the operator to check this, such as a sensor that detects parts on the opposite side - but with the latest board that I menntioned above with the 0805's it seems impossible, (forget barcoding.... with our current system its not feasible)

ANY IDEAS?? Thanks, Lee

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#4209

Re: Damaged/dislodged components when doing second side of double sided reflow | 8 May, 2000

The human machine is one of the most sophisticated know on this planet, "capable" of doing/thinking more than one task/thought at the same time. Sometimes the priorities get mixed up. So, if you have no simple computer or other gadgetry that�s able to do the simple tasks you would be well advised using that good old tally sheet each time you start a new job. Other companies I know use it and the operators have to sign for each adjustment and check that�s to be made before the first run. I assume you have to change the support manually, so you need somekind of reminder for the operators.

M2C

Wolfgang

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armin tan

#4210

Re: Damaged/dislodged components when doing second side of double sided reflow | 9 May, 2000

Create a checklist and include that in the checklist during conversion...etc...

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#4211

Re: Damaged/dislodged components when doing second side of double sided reflow | 11 May, 2000

I assume your oven has a "board width" setting for every board and the conveyor width is automatically adjusted as soon as you select the profile/recipe...

For the double sided reflow boards, I would set the width 1 inch (or another rounded amount) less than the real width so that the first board will not go through. That's gonna be a reminder to the operator to adjust the center support and the exact conveyor width..

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