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Dross or Dark Green Mud Found in HAL machine

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#88120

Dross or Dark Green Mud Found in HAL machine | 21 June, 2022

hi,

I have supplied 100 kg Solder Rods 63/37 to my customer for their New HASL Machine. Once they filled HASL Tank with 80 kgs with fresh Solder (Oily Mud like Dark Green Color Dross like substance was found flowing)

This Substance started on daily basis and during HASL Process and that mud like substance was also seen on PCBS during process and customer was surprised and complained to us about this issue and they are asking for Solder Replacement as they cannot use this Solder in their machine.

We checked with Solder Manufacture but they said there is no problem in Solder and Tried troubleshooting also as per below. 1) Solder Bath Sample tested same was found ok. 2) Checked HAL Flux Same was found ok. 3) Mud Like substance cannot be tested as same is not getting dry after kept in sun also for Drying no result. 4) Checked & Tested Machine Temperature and Heaters No issues. 5) Checked Impeler No Issues found ok.

I want to know the reason how this Mud like substance was getting generated in Machine and Solder is also wasted and could not resolve this.

Can anyone suggest or inform us how to resolve above issues.

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#88123

Dross or Dark Green Mud Found in HAL machine | 21 June, 2022

Are they applying a dross reducing powder, like what you would use in a Wave solder pot?

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#88124

Dross or Dark Green Mud Found in HAL machine | 21 June, 2022

No. They are not using any dross reducer.

I

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#88125

Dross or Dark Green Mud Found in HAL machine | 21 June, 2022

#88128

Dross or Dark Green Mud Found in HAL machine | 21 June, 2022

I received an email from the OP and I will not be connecting on WHATSAPP.

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#88138

Dark Green Mud Like Solder Found in HAL machine while Soldering | 25 June, 2022

Any Reply to this Photos or any update

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#88159

Dross or Dark Green Mud Found in HAL machine | 2 July, 2022

Hello !

I got exp only with leadfree HASL, but maybe the same problems apply. Also, the leaded HASL has probably lower process temperature.

This could be copper, which has settled to the tank bottom. With leadfree, the copper is removed from molten solution by reducing temperature and letting it settle about 4 hours. Copper sinks to the bottom and is lifted out with metal sieve.

There is always copper in HASL as the copper from PCB goes into solution. I dont know, how fast it solves into leaded HASL but in leadfree, temperatures are high and the copper migration is remarkable.

Also, the green color may suggest it as copper dross oxide will be probably green.

So I would check following

1) remove all clean solder from solderpot 2) clean the solderpot and all fixtures (this is a messy job and is probably overlooked) 3) put the solder back and melt. Check, if the mixer (solder pump) is correctly operating. 4) take a sample and order metallurgical analysis. Nowadays, even the scrapyards have portable device that can do it 5) check if its manuf specified limits 6) if too much copper, let the copper sink to the bottom. I cant say the correct temp for leaded alloy, ask the manufacturer

And also 1) maybe the pre-cleaning unit and flux application is bad (too much flux or PCBs not rinsed well after acid cleaning)

2) is the soldermask OK after HASL ?

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