Cleaning a Used (Preowned) Selective Solder Machine

Hi Dan,

you got the basics, so follow your plan. With these machines the most critical part is the fluxer. Most of the m get clogged easily and should be maintained very good.So if there is any tubing, fitting or other type of connector that might be clogging or leaking in the flux system, change it immediately. In my opinion these type of equipment should be cleaned and maintained daily to keep it running without having many issues. So I would put the effort to teach operators to take a good care of the equipment. Regards, Emil

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The key to longevity in any automated soldering machine is in the preventative maintenance. If the machine has had regular maintenance preformed on it, your job will be that much easier.

The 1st thing I would do is to either throw out the solder that came in the machine, or at a minimum send a sample out for analysis. You cant know what contaminates are present until you do. A lot of solder suppliers will do this for free in exchange for you buying your solder from them. If you have to pay for it, you can expect to pay 45-$85. Once you empty the solder reservoir, scrape down the sides of the tank and pump pieces with a metal putty knife and a wire brush. Heating the machine up may make the tank easier to clean, but it also opens up the ability to burn yourself so use caution.

You will also need to drain and dispose of any flux left in the tank. Glove up and (depending on how dirty it is) prepare to spend the better part of the day tearing down, cleaning, and reassembling the fluxing system.

Once you get the machine in operation look up what the manufacturer recommends for maintenance, and have your machine maintenance guy stay on top of them. Any machine that sprays flux into the air needs regular attention. You will need proper exhaust set up for the machine as well. Too little and you will be adding to the flux build up in the machine, too much and you wont get good coverage. Follow manufactures guidelines.

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You should also remove all the pump parts and clean them, checking the bearings and seals. Clean completely the parts that allow the solder to flow back into the pot; ours have a spiral that fills with dross.

Treat yourself to new nozzles. Tinning of a wet nozzle is critical so the solder flows over evenly. That can cause the most frustration in selective soldering. The metal erodes in RoHS solder so the top may not be square. Get the proper flux for the metal of the nozzle, usually stainless steel flux.

If your machine has threaded nozzles, buy a tap and die to clean out the threads of the pump and nozzles. It makes life easier as they get used.

If it is an old machine look for solder splashes in bad places such as sensors and connectors. The drive system rails can collect junk too.

And indeed the fluxer is sensitive to clogs so clean it out, purge the system with alcohol and refill with a flux that is appropriate for the type of fluxer. You may have to retune the flux settings for it to work with your flux.

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Problem with cleaning these machines is once you start it's easy to get carried away. ;)

We cleaned our SPA-400F a few months ago, had been offline for a while as we were using our SPA-250.

It started as just a clean and to replace all the flux pipes etc. We ended up fully stripping the machine back to the shell then rebuilt the whole thing and replaced belts etc. If I could post a picture you would be surprised how it looks just as the frame.

1. Empty the pot completely of any solder. Watch you don't leave the heater on too long with no solder in it when emptying. you can get most out with a ladle while it is hot.

2. I'd replace all the flux pipes as if it's not been used for a while these may be perished and it's easy enough to replace them.

3. Make sure the heater element is as close to the top of the pot as possible.

4. When heating the pot up, keep the machine covers closed as the solder can spit out. It's useful to turn the heater off every 15 mins for a bit to prevent this.

5. Fluxer is key as has been said. We always clean the fluxer at the end of every day and do this throughout the day depending on load.

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