NordicCNC's build log

[jarjar]

Hi,

Some comments in no particular order, assuming you want to build a decent machine and not a toy:

- 1400 x 1000 x 200 mm is a _huge_ working area. I would expect a machine that size to weighs at least 1500 kg.

About servos:
- those 180W JMC servos are toys and seriously underpowered if you want decent speeds. If you want to go servos, use some proper ones. Delta servos are cheap and good. You need to size the motors depending on the max feed/rapid rates and accelerations you seek. 400W is probably the bare minimum.
- Personally I expect a router this size to be fast, I would target 30m/min (1000 ipm) and maybe 0.5g accel.

About ballscrews:
- 10mm pitch ballscrew would be the minimum I'd use, without any reduction. With servos direct-drive is the best and the cheapest. Good pulleys are expensive, and add unwanted inertia to the system. Servos are usually rated at 3000rpm, with 10mm pitch this gives you a max speed of 30m/min.
- 5mm pitch ballscrew is acceptable for the Z axis. Again without reduction. If you really want pulleys for space issues, use 1:1.
- Ballscrew diameter: you need to calculate it depending on the desired max speed. A ballscrew 1400mm long that don't whip at 3000rpm with fixed-floating ends is around 60mm diameter... If this sounds too big you can go with rotating ballnut (complex) or larger pitch. 20mm pitch would be ideal and you would only need 32mm ballscrews.

About rails:
- don't bother with anything less than 25mm. For the simple reason that 20 rails use M5 bolts and require tighter drilling positioning tolerances.