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SMT electronics assembly manufacturing forum.


DFM for Wave

Views: 1719

dave

#42624

DFM for Wave | 10 July, 2006

Hi All,

I am looking for some DFM for wave process.

Is there IPC standard ?

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RDR

#42641

DFM for Wave | 10 July, 2006

782 has some layout info. that is very helpful

Russ

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#42644

DFM for Wave | 10 July, 2006

Dave Try: * IPC-2221 - Generic Standard On Printed Board Design * IPC-2222 - Sectional Design Standard For Printed Board For Organic Printed Boards

Our old [euphemistically] friend Earl Moon has written extensively on DFM. Look at his site: http://www.moonmanondarkside.com

We have no relationship, nor receive benefit from the company referenced above.

Russ We think of SM-782 [Surface Mount Design & Land Pattern Standard] as pretty solidly in the surface mount category, rather than the wave solder category. Does 782 have SM land layouts for use with a wave?

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#42651

DFM for Wave | 11 July, 2006

No relationship? Brokeback Engineering? :)

I would've looked at his site, but it hurts my eyes. It's almost as if he uses that loud color on purpose, despite past criticisms.

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Chunks

#42653

DFM for Wave | 11 July, 2006

I would be careful venturing on Moon Mans site. It has some good reading, but it does appear he's looking for a fight.

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RDR

#42655

DFM for Wave | 11 July, 2006

It sure does Dave, 782 has some recs regarding pad orientation and shape mods for wave soldering. I figured that this would be helpful here since most do not think of the SMT through wave portion and what it takes to make it work at the highest level of quality.

Russ

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dave

#42753

DFM for Wave | 17 July, 2006

Guys,

My problem is that I have a 10 up panel and I have to use a selective pallet to run it thru the wave process due to SMT on bottomside. However the yields are very poor. We have done everything to improve them with some good improvements along the way but we still have to rework the boards everytime on certain leads etc.

I am doing a report to tell the customer that they need to improve the layout or we will have to cost the rework as the defects are due to poor design not poor process.

The problems are obvious but I would like to reference some guidelines to back me up.

dave.

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RDR

#42754

DFM for Wave | 17 July, 2006

Okay, now we can get rolling here.

Here is a couple of things about selective wave that Ihave found very helpful

1. Make sure that no parts on back side are in excess of .15". if they are we skip; out in SMT and handsolder if labor costs justify.

2. chamfer all openings in wave fixure as much as possible, this permits tighter access due to reduced meniscus of solder in opening

3. Ensure that there is at a min. .100" between edge of anular ring and nearest SMT pad

this will help with fixtures and design a bit I hope.

Set the wave if you can to run the OMEGA (electrovert vibratory, other MFGrs may have similar function to break surface tension of solder)

Use Chip wave to get solder into tight areas in fixture.

Make sure flux coverage if foaming is complete and the fixtures are cool.

Make sure flux with spray nozzle is not being shadowed by fixture.

Just a couple of things that may help, good luck

Russ

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dave

#42762

DFM for Wave | 18 July, 2006

Hi Russ,

Thanks for the info.

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dave

#42767

DFM for Wave | 18 July, 2006

Guys,

what about hole to lead size?

is it lead size + 0.010' + tolerance

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