Re: Advice needed?.

--- In CAD_CAM_EDM_DRO@y..., "rmtuckeruk" <rmtucker@l...> wrote:

> Help!!!!.
> I am in the process of building and designing a gantry type
> mill/router.It macines approx 1500mm*1000mm*300mm.
> I am using leadscrews (16mm dia * 4mm pitch),with phospher bronze
> anti backlash nuts.These are driven from a 300oz stepper motor
> through a timing belt on 1:1 pulleys.
> I am currently only achieving 0.8"/sec max feed before the motor
> stalls.
> How can i improve this?.
> I am looking at new motors which are 700oz.
> If i detatch the belt the motors will actually run up to 3"/sec
> before stalling,so would i achieve anything by gearing down maybe

2:1

> to increase torque so increase speed.Or would ballscrews etc be the
> best bet.
> I would like to hear from anybody that has built or is building
> something similar.
>
> thanx
> mark

Mark,
You didn't specify your motor drive and power supply; they are both
possible limits on torque and speed. Best performance is with a
choppper drive and a power supply that delivers 20x the motor steady-
state rated voltage at "more than enough" peak current.

Also, with antibacklash nuts on an Acme screww it is really easy to
bind up the screws by trying to squeeze out that last bit of
backlash. Easy to try - just loosen them a bit and see if it makes a
difference.

Fred