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Solder paste transfer from jar to cartridge

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nrw

#61796

Solder paste transfer from jar to cartridge | 11 May, 2010

Hello,

I am in the process of setting up processes for a low volume SMT line for internal prototype production, where a 500g jar of solder paste would last weeks.

Our distributors only seem to want to supply 500g jars (anything else is significantly costlier), and I wish to minimise wastage by splitting up the new jars into 6oz semco cartridges prior to refrigeration, with no effect on the quality of the paste when it is finally used.

We have a centrifugal paste mixer, should the paste be mixed prior to separating into smaller portions?

Our workshop is air conditioned to ~20 degrees C, however should humidity be reduced as low as possible? (ideally 0% RH).

Any help people could provide would be appreciated!

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#61797

Solder paste transfer from jar to cartridge | 11 May, 2010

If you see flux separation mix the paste with a spatula before you transfer it. There is no need for a centrifugal mixer.

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#61798

Solder paste transfer from jar to cartridge | 11 May, 2010

Lower humidity:

Pros: Helps with mositure sentative devices.

Cons: 1)Paste exposed to the dry air during your porcess will dry out quicker. 2) Drier air promotes more ESD issues, i.e. more electrostatic generation.

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#61802

Solder paste transfer from jar to cartridge | 11 May, 2010

Paste for dispensing differs significantly from paste for printing. [B Toleno Henkel Loctite].

So, if you compare paste characteristics: Characteristic of paste||Printable ||Dispensable Viscosity [million centipoise]||0.8 to 1||0.2 to 0.4 Metal content [percent]||88 to 91||83 to 87 Key traits||Tackiness, slump & work life||Lubricity, flow & resistance

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#61806

Solder paste transfer from jar to cartridge | 11 May, 2010

Getting the paste from the jar and into the cartridge without entrapping air can be difficult. Can you not just transfer the 500g jar into smaller working jars? This way you can keep the bulk of your paste refrigerated until needed. Air is not your friend when working with paste.

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#61807

Solder paste transfer from jar to cartridge | 11 May, 2010

First, you mix the paste in the jar with the centrifugal thing-a-ma-jig. Then what? So, how are you going to get the paste from the jar into the syringe [cartridge], anyhow? Are you going to use an Atlas Tool? How are you going to de-air the syringe [cartridge]?

Second, have you looked at the online catalogs for electronic manufacturing stuff distributors, like Wassco, Techni-Tool, HMC, Marshall, Contact East, Jensen, etc? * Paste in 500g jars and 600g cartridges seems to have a similar unit cost. Why not use a cartridge? * 35g [or so] syringes seem to be readily available. Why not use syringes?

What's going on?

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#61813

Solder paste transfer from jar to cartridge | 13 May, 2010

The problems that could be introduced by attempting to transfer paste into alternate containers far outweighs the penalty of wastage of paste.My grandmother doesnt receive a rebate from the filling stations because she only travels 50 miles a month with her car these days.

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nrw

#61814

Solder paste transfer from jar to cartridge | 13 May, 2010

Thank you everyone, I realise the problems now and the whole exercise might not be worth the money saved, versus just throwing out the leftover paste.

I am based in Australia, so the number of players in this market is small and they know it. The problem buying smaller volumes from international distributors is the freight. To be economical it would have to be shipped by USPS airmail, and thus exposed to who knows what environmental conditions.

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#61815

Solder paste transfer from jar to cartridge | 13 May, 2010

it is true.My supplier only sell the sodler paste in Jar,1 jar must have 500g( minimum), although we wanted 250g par jar.

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