Homebrew PCBs

Stefan Trethan wrote:
> Well, Russel,
> 
> maybe we can all stop bickering and rather use the valuable answer time
> for generating useful posts.
> 
> You say you have made such a machine, tell me more.
> Especially tell me what you do about your software, and
> how the pneuamtic plunger works. i think i have all components
> for a pneumatic system here (pump, pressure regulator, several solenoid 
> valves).
> I think it has some potential advantages and would like to give it a try.
> I do not remember exactly how the air was coupled to the syringe, would it 
> work
> to simply apply the air pressure to the already existing plunger-back and 
> seal
> off the syringe housing?
> 
> thanks

Hi,
I didn't intend to get anyones hopes high. I've designed it, and tested
most components/ideas in isolation, but haven't built the whole thing.
It has 12V/10A DC servos and is a design that is scalable from a 1m x 1m
area up to as large as needed such as 1.2m x 2.4m or larger (it's not
just for PCBs). Z axis travel is atleast 20cm. The software runs on a
linux pc, and sends basic shapes (path commands) to the microcontroller
on the machine. The paste dispenser uses metal plungers (i have a design
that also uses a single solenoid) instead of compressed air. The variable
viscosity due to batch variations, age, and temperature makes the flow of
solder paste unpredictable for a given air pressure. No plastic syringe will
be used. XYZ movement resolution will be 2.5um. Machine flexing will exceed
this, and the shaft/gearing backlash. Head movement at max servo speed will
be "quick" (60V servo drive ability), but i haven't got those numbers with
me atm. Motors are the most expensive part (AUS$120). Everything else is
*very* cheap. I wasn't going to say anything until i'd built it. I'm doing
the software between other jobs, so it'll take a while.