- Thu Nov 17, 2011 2:06 am
#135843
So I bought a Chinese pneumatic solder paste dispenser ( a bit like this one - http://www.ebay.co.uk/itm/SMT-Solder-Pa ... 336de411b4 ), but I'm having a hard time trying to get the solder to dispense out the nozzle at a fine enough width ...I work down to SOT-23-6 footprints, but the dispenser nozzle dispenses a blob, rather than a precise but of solder paste.
So, to my questions...
1. What viscosity should the solder paste be (presently I'm using some solder paste sold by Deal Extreme - but it doesn't come in a syringe...so I manually put it into one of the syringes supplied with the dispenser ....but it strikes me that it's a bit thick....& sure enough if I put my finest nozzle on there...nothing comes out (though this could be my compressor being a bit weak)
2. Can anyone recommend a (cheap) solder paste already in a syringe with a nozzle fine enough to do sot23-6?
3. Failing that, what nozzle size should I be using (to help you visualize....SOT23-6 is about one step down from SOIC pitch ....not ludicrously small like MSOP etc, but still 'tight')
The other problem I have is that when the solder paste does come out of the nozzle....it doesn't 'grab'/adhere to the copper pad very well, when I lift the nozzle away, the solder comes away with it...meaning I have to then go back & try & wipe/drag it off the nozzle onto the copper pad - I'm sure this isn't how it's meant to be.
Basically, I'm not getting along with this method very well ..so any related top tips would be most welcome!
So, to my questions...
1. What viscosity should the solder paste be (presently I'm using some solder paste sold by Deal Extreme - but it doesn't come in a syringe...so I manually put it into one of the syringes supplied with the dispenser ....but it strikes me that it's a bit thick....& sure enough if I put my finest nozzle on there...nothing comes out (though this could be my compressor being a bit weak)
2. Can anyone recommend a (cheap) solder paste already in a syringe with a nozzle fine enough to do sot23-6?
3. Failing that, what nozzle size should I be using (to help you visualize....SOT23-6 is about one step down from SOIC pitch ....not ludicrously small like MSOP etc, but still 'tight')
The other problem I have is that when the solder paste does come out of the nozzle....it doesn't 'grab'/adhere to the copper pad very well, when I lift the nozzle away, the solder comes away with it...meaning I have to then go back & try & wipe/drag it off the nozzle onto the copper pad - I'm sure this isn't how it's meant to be.
Basically, I'm not getting along with this method very well ..so any related top tips would be most welcome!