[ballchain]

Hello All,

I've been visiting CNCZone for awhile now, but just registered today.

I've been building a homemade CNC mill (which is now turning into a Frankenstein project) and have a question...

How much stepper motor power is needed for a small CNC mill? I've aquired 4 so far, 3 being around 150 in-oz, and one being 230 in-oz.

I custom made the spindle from scratch, and with the motor I'm using to turn it, things are starting to get heavy. I'm estimating around 15lbs+ will be on the Z-Axis. Can the 230 in-oz motor handle that, or do I need to go larger?

I'm using a centrally located 1/2" Ballscrew and 2 - Linear slides mounted on either side of the table. (sort of like a router gantry) The motor is a 3/4 horse (variable-speed) directly mounted to the spindle which is made of 4140 steel machined to accept Morse Taper #2. The spindle and housing weigh about 3-4 pounds, the motor about 10 pounds, and the aluminum plate mount weighs another couple.

Should I get a bigger stepper, or make a counter-weight system?

Any advice would be greatly appreciated. I started my design planning for a mini CNC mill, but I'm doing most of the work at my buddy's machine shop, and he keeps getting me to upsize my design. (They do large/heavy projects, so naturally they aren't used to "little" or "mini")

[Pres]

Should I get a bigger stepper, or make a counter-weight system?

I'd try a counterweight, gas strut, or long spring.
(heaviest weight), (mid) , (lightest).

Pres

[revricky]

Hi-
On the Rockcliff forum awhle back the same question was asked and the answer given by one of the members is: A 200 oz-in motor with a 1/4-20 lead screw can push, pull or move 15-18 lbs without any problem. Hope this helps.

revricky

[BobF]

Many of the manufacturers publish data that may help.
Here is one.
http://www.roton.com/Engineering_Data.aspx?line=Hi-Lead