Dispensing solder paste with a syringe, by hand, gets old pretty quick. Kinda painful and tiring and There’s Got To Be A Better Way!
I’ve seen air-powered glue dispensers used for solder and I love that idea, but from all reports, the compressibility of air makes the flow really inconsistent and hard to control.
So, like all quick projects I do, I let it sit for years while I pondered the issue.
After deciding on a strategy that would allow me to put the least amount of effort into this as humanly possible, I bought the following:
DC motor with gearbox and threaded rod:
Brass heat-set inserts:
1mL syringes:
Copper tubing:
And a pile of electronics I already had kicking around.
I 3D printed a syringe-motor adapter:
I soldered an insert onto the brass tube, and then with the motor, I had a linear actuator.
Pile of electronics and rudimentary code:
Neat:
I also glued the rubber gasket/tip to the copper tube.
Old old old solder paste goes in:
Then the actuator:
Little bit dribbly at first:
Not bad for a first test:
Obviously not perfect, though. The mechanism stopped being able to force the crusty paste through the needle, and broke the (admittedly flimsy) 3D printed bracket when the motor tried to exit its situation.
The bracket as a mechanical fuse might not even be a bad idea to keep around. The real problem was the paste, it was toast.
Some code changes would be neat as well. Pullback to prevent dripping. The repo is here, it is very simple.