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Problem with less soldering material on the pins

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#77440

Problem with less soldering material on the pins | 20 April, 2017

Hello to all, I am having a serious problem on my ersa versaflow 3 machine. This is a selective soldering machine and a problem is in less soldering material on the pins, you can see it in the picture http://imgur.com/a/FC2a1 Do you have any idea how to solve this? I am cleaning the nozzle every one hour,the pots every three days.

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#77441

Problem with less soldering material on the pins | 20 April, 2017

Mile,

Please tell me more about your soldering process:

- Are soldering process parameters the same for all three pins? - Is unsoldered pin connected to thermal heavy copper polygon? - What is your board surface finish? HASL? - Sn/Pb or LF process?

Initially this seems like dewetting. Dewetting is commonly caused by poor surface finish quality. Pad might have been contaminated somewhere at PCB house side.

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#77442

Problem with less soldering material on the pins | 20 April, 2017

Parameters are all the same, the pin is only connected to the capacitor.I will check about surface finish with my logistics.

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#77443

Problem with less soldering material on the pins | 20 April, 2017

The hole is too big, you should reduce the size in the next PCB revision.

The middle joint is soldered at low temperature you can see how the solder didn't distributed evently and cooled on waves.

The solder joint at the bottom didn't wet the capacitor pin and if you pull it it will went out of the solder joint.

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#77444

Problem with less soldering material on the pins | 20 April, 2017

The temperature in the pots are 310C

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#77445

Problem with less soldering material on the pins | 20 April, 2017

To overcome the dewetting issues of the past, a number of techniques have been used such as alternating directions on the wetted nozzle; this helps to avoid the solder biasing to one side causing the other side to oxidize and de-wet. Another method of combatting this issue is to briefly burst the pump after a solder drop-off. This allows the solder to quickly recoat and re-establish a good wetted flow over all sides.

Cam someone explain to me how can i try this?

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#77448

Problem with less soldering material on the pins | 20 April, 2017

Surface finish is Tin 7 microns thick

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#77508

Problem with less soldering material on the pins | 1 May, 2017

Looks like you have bad wetting. I will do in this order as it is easier to troubleshoot starting with the machine and transitioning to the PCB:

1. First clean some bare PCBs really good and try again. 2. Check thermal profile 3. Check flux - amount, repeatability 4. Stay longer on this joint with the nozzle- try 10 seconds if that part allows it 5.PCB - try another supplier and or a different finish - this sohuld be negotiated with your customer.

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Metcal soldering rework

SMT Replacement Nozzles