How big of motors do I need

[CNC Brute]

Not sure if I asked this, I think I did, but I'm looking for a more defined answer.

My table is 5 x 5 and I want to cut, and sculpt wood and engrave aluminum (not cut through on a regular basis).

So how do I figure out how big of motors to use? I'm trying to keep the cost down so I'm thinking steppers and xylotex.

This will be my first and it'll use a similar system to the balsaman 2 router. 80/20 frame, but I'm using bearings in the groove instead of thk bearings.

Anyone have like a mathematical equation or something?

Big thanks,

Matt

[HomeCNC]

this is a very subjective question. Lets say you build a router and it has very little friction on the movement of the axies. Meaning it only takes a few oz to move it. Well you could place very weak steppers on it like 60 oz/in. You would need to move very slow like 1 or 2 IPM and take very light cuts, but they would work.

I think for you to be happy with the performance of the machine you will need something between 150 to 300 oz/in motors.

Are you planing to run them straight to the screw or will you go through a pulley ratio? You get speed at 1:1. You get strength at 2:1, when your motor turns more than the screw shaft.

[CNC Brute]

I'm not sure about pulley systems. More than likely I will use a two screw system with a belt.

How do I design for gearing ratio? I don't think I'll have a good idea what needs to be changed until AFTER I build the machine, but you gave me a good place to start. Thanks.

[Bloy2004]

I'd say to build your machine as you envision it, keeping the motor mounts open for adjustments to accommodate different sized pulleys and belts. This way your experimentation with ratios, motor sizes, etc. can easily be implemented.