I want to make a pump for a custom espresso machine that focuses on water flow rate control rather than pressure. I'll to use a piston (I'm trying a 40 mm pneumatic cylinder first) and push water at around 1ml/s. The presures are high so I was thinking of pushing a 6:1 lever arm with a ballscrew. I need to know what would a good stepper motor to use.
So... I need a motor/gearbox/ballscrew to push a load of 30 kg at around 3 mm/s for a distance of 250mm (those figures are adjustable to some extent, I could increase the load and slow the speed, or increase the distance and speed with lower load)
I guess I'd use a 1 mm Lead ballscrew ... ?
I expect I am better off with something bigger than nema 17...? Nema 23 and 50:1
What sort motor rpm should I aim for?
Any advice appreciated. Cheers