Re: sprockets?

--- In CAD_CAM_EDM_DRO@y..., "jeffgnu" <jfbell@e...> wrote:

>
> (snip).. be a good ratio from stepper to rod sprockets? 1:1, 1:2

The stepper

> have a 180 S/R.
>
> How thick of a timing belt should I be looking at? 3/8", 1/2" or ???
>

There are more experienced builders in the group but I will give it a
stab. You should consider the following in order to answer the
questions you pose

1. What is your target speed in IPM (Inches per minute). Depending
on the material you are cutting it could be from 10 IPM to over 60
with rapid (non-cutting) moves double that. Soft pine cuts quick
while Maple and Oak need slower feeds. Once you have a target IPM
you can do the math on what it will take to get this move rates given
the pitch of your Acme screw and the steps it takes to make one rev
(half stepping, quarter stepping??)

2. You will always trade speed for torque. Larger ratio "sprockets"
(toothed pulleys) give you more power to move the router through
tough material at the expense of speed.

3. 3/8" belts are probably just fine. Just provide a method to move
your motor to keep the belts tight.


While its fun to build things as a learning experience, with just a
medium amount of more attention to detail you can end up with a
machine that is very usable and accurate. 34 steppers can be used to
build a fairly robust table (although your motors are on the low end
of the torque range). Whatever you do have FUN!