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The connector is falling down in the second reflow

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we have a problem : The connector is falling down in the sec... - Feb 11, 2020 by DJO MJ  

#84400

Connector is falling down in the second reflow | 11 February, 2020

we have a problem : The connector is falling down in the second reflow. This connector is mounted in the first side. You can find attached the reflow profil we work with and a photo of the connector. We tryed with under_film but the connector is still falling down. Any recomendation please!! It's a critical problem.

Thank you for your quick reply.

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#84401

Connector is falling down in the second reflow | 11 February, 2020

If all else fails, you can always chipbond the part. Would it be possible to run this side as the second reflow?

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#84406

Connector is falling down in the second reflow | 11 February, 2020

To predict whether or not a first pass part is going to come off during the second pass you need to calculate the ratio of weight/soldered surface area. According to a couple of different sources that I've dug up, maximum is around 44 grams/in.^2.

I'd guess that the connector you're dealing with is well beyond that, and the fact that the weight distribution is asymmetrical isn't helping.

For a low volume and infrequent jobs, I'd probably just manually add chip-bonder to each end of the connector before the second pass like Phil suggested. For high volume repeat builds I'd probably think about using a fluid dispenser after my stencil printer.

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#84420

Connector is falling down in the second reflow | 12 February, 2020

Hi there , I agree with phil .. but we cannot change the architecture of the card to mount the connector on the 2nd side. Steve , we are producing large series, so we can't manually ship bond the connector .. for the moment, we cannot invest in a glue dispensing robot .. we are looking for a solution to be streamed with the production line or a component that will be mounted automatically by the laying machines (for example the under film: we are doing tests with it, and until the moment no confident result) .. do you have an idea on an adhesive component that can be put under the connector ?? another type of under film, resin or something else ...

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#84422

Connector is falling down in the second reflow | 12 February, 2020

If you have control of the solder alloy you're able to use on the product, you could run a lower temp solder on the second side and try to avoid the first side entering reflow.

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#84423

Connector is falling down in the second reflow | 12 February, 2020

We can't do that because we are using dual ligne reflow oven..So the two sides of PCB are soldered with the same reflow profil.

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#84424

Connector is falling down in the second reflow | 12 February, 2020

Would you consider a light reflow pallet on second side holding the connetors in place and preventing them from moving?

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#84425

Connector is falling down in the second reflow | 12 February, 2020

Would you consider a light reflow pallet on second side holding the connectors in place and preventing them from moving?

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#84427

Connector is falling down in the second reflow | 12 February, 2020

we have already taken this idea into consideration but as a plan b .. like i said before, we are producing large series of cards, then the lights reflow pallet will disrupt the normal production process (storage in the racks, convoys, machine screen printing ..), that will force us all to change to adapt to this new process ..we are eliminating this solution for the moment..

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#84428

Connector is falling down in the second reflow | 12 February, 2020

No to redesign, no to glue dispensing and no to pallets. Now you should change gravity ...or pray :) I am interested to see what other solution you can come up with.

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#84437

Connector is falling down in the second reflow | 12 February, 2020

Hahaha we already praying.. There is always a solution for any problems.. That's why am trying to do brainstorming with you all.. It's a pleasure to share ideas

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SMTA-Alex

#84438

Connector is falling down in the second reflow | 12 February, 2020

I see that the connector has plastic alignment pins. Is there any reason you can squirt a drop hi-temp "Crazy" glue into each hole, after the bottom side assembly and before printing the top side?

This message was posted via the Electronics Forum @ SMTASMTA

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#84443

Connector is falling down in the second reflow | 13 February, 2020

we are obliged by customer specifications that there will be no glue despensing process on the production line..

also that the glue dispensing process is very complicated for this case .. we could have glue splash on top surface of pcb so that will cause screen printing problems (the holes are a lot small RND 1.6)

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#84459

Connector is falling down in the second reflow | 14 February, 2020

OK, you can't glue, Pallet Guys pallets are out the door, dual line reflow prevents from any lower temp solder paste.... Do you have a 3D printer? Are there parts underneath the connector in question? Measure the PCB thickness, pint out a custom hold down that captures the bottom edge of the PCB with slight contact with the top surface of the connector (Slight contact as not to smear the past man!) us a silicone infused resin, Go Get Em'!

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#84518

Connector is falling down in the second reflow | 24 February, 2020

It may because the part weight is too high so a weight to connector soldering area>=0.08g/mm2, make it less than 0.08. And maybe the connector gravity center location is a cause also.

If no machine issue (vibration, wind,etc), and you cannot change the design/material then you can use SMT glue to fix the connector during reflow.

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#84521

Connector is falling down in the second reflow | 24 February, 2020

Traditionally these connectors are riveted to the board on higher volume telecommunication applications.

sarason

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On-board Dispensing of Dots & Lines

Reflow Oven