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Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Tin Lead Solder Paste

Views: 934

#74368

Tin Lead Solder Paste | 12 August, 2015

Hello, I have a problem with the solder paste process, I need a solder paste with no Start-up Time because We do not work 24 hours in the manufacturing process, we works only 8 hours a day and at the finish we need to store the paste in the refrigerator. In the next day we need to wait the Start-up Time again. We find a lead-free paste but our process is tin lead: http://soldergamechanger.com/ I hope you can help me! We use SH6309-RMA solder paste: http://www.smtsolderpaste.com/product-info.php?tin-lead-no-clean-type3-500g-jar-product-page-pid4.html/ -Juan

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#74375

Tin Lead Solder Paste | 12 August, 2015

Here is our solution: We run the assembly line 40 hours per week and use 500g cartridges of solder. We take 1 cartridge out Monday morning and leave it out until the end of the Friday shift when it is put back into the refrigerator. That means you only have 1 "start-up time" per week. It takes us 8-10 working days to use up 1 cartridge. We have not seen any drop in solder paste/flux performance as we get close to the end of the cartridge. All of our solder joints pass IPC class 2 criteria.

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#74382

Tin Lead Solder Paste | 13 August, 2015

Hi Juan,

I think if you check your Solder Paste's Data Sheet, you will find that your Solder Paste can be stored at Room Temperature for up to four weeks. There is no need to put your paste back into the refrigerator after every shift.

If it makes you nervous, or if you don't trust the datasheet, you can always do a DOE and qualify your paste after exceeding a pre-determined exposure time.

http://www.researchgate.net/publication/46480568_Optimization_Of_Solder_Paste_Printing_Parameters_Using_Design_Of_Experiments_(DOE)

Trust your data.

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#74392

Tin Lead Solder Paste | 14 August, 2015

I don't know what paste you are using, but most of the leading brands can stay out of the fridge for up to 6 months.The paste you already took out of the cartridge should last you several days - up to one week, depending on your room temperature and humidity. So, what I am trying to say is:

1. You should always have 2-3 cartridges out that are ready for use. 2. The paste should never go back to your fridge. Once it is dry, just toss it.

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