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Wave Solder question

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I'm having an issue with a particular board we run in our wa... - May 21, 2012 by Chris  

Protrusion is 1 mm. ... - May 22, 2012 by Chris  

Square ... - May 22, 2012 by Chris  

Here is a picture. ... - May 22, 2012 by Chris  

#66389

Wave Solder question | 21 May, 2012

I'm having an issue with a particular board we run in our wave solder. it has a USB connector with 4 pins that are 3mm x3mm square. we are constantly getting abridge across at least two of the pins, but sometimes all 4. I've run out of ideas on how to eliminate it. I've done the basic things, change flux pressure, slowed it down, sped it up, adjusted the wave. The rest of the board is fine. I will note it is on the trailing edge as it goes through the wave, and I have turned it 180 with no luck.

Thanks in advance

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#66392

Wave Solder question | 21 May, 2012

What is the lead protrusion?

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#66395

Wave Solder question | 22 May, 2012

Does the part seem to flow properly? Are your land patterns to IPC spec? It could be a design issue.

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#66399

Wave Solder question | 22 May, 2012

Bridging Causes: Insufficient flux, excessive pre-heat, high conveyor speed, solder contamination [AIM Solder]

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#66400

Wave Solder question | 22 May, 2012

Protrusion is 1 mm.

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#66401

Wave Solder question | 22 May, 2012

What is the configuration of these 4 pins? Square or inline? o o or o o o o o o

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#66402

Wave Solder question | 22 May, 2012

Square

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#66403

Wave Solder question | 22 May, 2012

are the briges like this (O-O) parallel to the wave or random parallel and perpendicular to the wave

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#66404

Wave Solder question | 22 May, 2012

Forgot something how is the top fill on the connector?

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#66406

Wave Solder question | 22 May, 2012

I can't see the fill as they are underneath the connector. As far as the direction 95% seem to be perpendicular to the wave with the occasional parallel and some all the way around(not many). I have tried altering the speed, I've played with the fluxer recipe, insured proper board temp. I'm in the process of getting a picture posted.

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#66408

Wave Solder question | 22 May, 2012

Here is a picture.

Attachments:

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#66409

Wave Solder question | 22 May, 2012

It sound like this connector is a serious head sink which can be solved with more preheat or slower conveyer speed. It might also be a combination of the heat sinking capability of the connector together with encapsulated flux underneath the connector. When the encapsulated flux hits the wave the flux solvent start boiling which creates a cooling effect and the flux vapors also disturb proper solder flow.

Do you hear sizzling when the connector hits the wave?

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#66410

Wave Solder question | 22 May, 2012

Sizzling would be hard to hear our machine has forced air preheaters along with all the other ambient noise, so I'm going to say no sizzling. I've tried really slowing the conveyor down to see if it helped, I saw no noticeable difference.

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#66411

Wave Solder question | 22 May, 2012

A picture of the top side of the connector would be helpfull too. I assume the 2 large leads in the front are part of that connector too.

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#66412

Wave Solder question | 22 May, 2012

These are the hold down clips for the connector. I'll post the top side picture asap.

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#66413

Wave Solder question | 22 May, 2012

Lead spacing is probably an issue here. It would be better if your lead pattern was staggered, like the RJ-45 to the right. It appears there may not be enough flux on this part of the pcb.

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#66415

Wave Solder question | 22 May, 2012

The spacing, and the length as everything else on this board solders great. As far as the amount of flux goes, I altered the fluxer recipe to both spray more and less to see if either had an effect, again nothing noticable...well less was noticable, nothing changed with more. Top side picture attached.

Thanks

Attachments:

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#66416

Wave Solder question | 22 May, 2012

Chris,

If the short in the picture is parallel to the wave turning the board 90Deg will solve the issue. Because then the lagest spacing will face the wave parallel and the smallest space perpendicular.

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#66417

Wave Solder question | 22 May, 2012

Do you have anything else on this board with a similar land pattern?

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#66419

Wave Solder question | 22 May, 2012

> Chris, > > If the short in the picture is parallel > to the wave turning the board 90Deg will solve > the issue. Because then the lagest spacing will > face the wave parallel and the smallest space > perpendicular.

Yes, good point Patrick. Hopefully the OP has enough spacing on the North-South perimeter of the pcb that will allow for board rotation.

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#66421

Wave Solder question | 22 May, 2012

I will give 90 deg turn a try, I want to say we've tried this in the past, but my memory is not what it once was, and the operators can't recall either. Thanks for the input, I'll keep you updated.

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#66422

Wave Solder question | 22 May, 2012

Well no luck on the rotation, tried all directions to no avail, seemed to bridge in the same direction.

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#66423

Wave Solder question | 22 May, 2012

So it went from parallel to perpendicular with regards to the wave, or it stayed parallel?

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#66425

Wave Solder question | 22 May, 2012

good question Reese In addition what type of flux do you use? after seeing the board am pretty sure it's a no-clean but is the flux water based (VOC free) or solvent (alcohol based) Maybe one more question what brand and type of wave machine you use?

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#66426

Wave Solder question | 22 May, 2012

Reese, no stayed perpendicular in regards to the wave, however on the 90deg clockwise turn from original(connector trailing)we had some bridging on the pins on the right in my first picture.

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#66428

Wave Solder question | 22 May, 2012

Patrick, correct, no clean alcohol based. Machine is a Vitonics Delta Wave.

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#66433

Wave Solder question | 23 May, 2012

Since you have an alcohol based flux one more thing you can try to eliminate flux encapsulation under the connector. Is flux a board and remove when fluxed. Let the board sit for an hour to assure all solvents are evaporated and place the board in the machine (after the fluxer) solder and see if this helps.

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#66435

Wave Solder question | 23 May, 2012

Try trimming the leads to no more than 0.020" instead of 0.040" (1mm). The extra labor on the front end may save on the back end especially if almost all your boards have bridges in this area.

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#66439

Wave Solder question | 23 May, 2012

Patrick and Dean, I'll try both suggestions in the next day or two and let you know what I find.

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#66451

Wave Solder question | 27 May, 2012

I would suggest that the pad size vs lead length vs lead pitch are helping cause issue if rest of PCB is ok

From DFM , yes reducing lead length - experiement or reducing pad diameter could help.

Also flux can still be issue, try fluxing part prior to fluxing in machine manually - then run...

Also I have founc activity of fluxes can vary and seen issues like this dissapear by useing a higher activity flux - newer VOC-Free NC fluxes can be good here vs typical solvent based.

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aj

#66456

Wave Solder question | 29 May, 2012

spacing is very tight but you should be able to get it right...

If possible try and run it at 45 degrees over the wave and see how you get on...

we had a similar problem and this improved things dramatically ( but we had a selective pallet that was mounted in a carrier to allow this rotation)...

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#66473

Wave Solder question | 31 May, 2012

Yes, 45 degree will kill the shadowing effect. YOu can also consider the teardrop on its land. No need to tilt to 45 degree.

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#66484

Wave Solder question | 1 June, 2012

Try a simple solder mask. I use Chemtronics. A bottle is only arond $20 and is as easy to apply as it is to remove. A cheap, quick fix.

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#66485

Wave Solder question | 1 June, 2012

Tried fluxing, then letting it sit for an hour and then running it through post fluxer...no bridging, only tried one board though, we're pretty busy at the wave so I have to slide things in between jobs. Also cutting the leads down also worked, but time consuming, I feel the solder mask then hand solder the part would be as efficient.

Thanks for all the suggestions

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#66486

Wave Solder question | 1 June, 2012

Perhaps apply the through hole part, solder mask only one barrel. Then hand solder that single leg.

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