Re: stepper driver help

> Most importantly, what screws are you using. They, more than

anything

> determine the required characteristics of the drive and motor.
> PK

The table (its a mini mill) has quite well made achme screws with a
2mm pitch- I have set these up to have very little 'backlash' (0.02-
0.03mm) and they are very free even just using the supplied backlash
adjustments, which, while they work, don`t seem to be ideal. With
some work I am thinking these can be improved on.

In the future I would like to think I`ll go to ball screws, but for
now, cost is a major factor- so el-cheapo achme it is.

I will make some toothed pullies for whatever toothed belts I can
find- this frees me up a little in terms of what reduction ratios I
can use, and previously 1:1.5 or 1:2 was mentioned. Again, I have
no experience of what the associated merits and problems are with
the stepper to lead screw conections are- I have read about
resonance being an issue but I just have not 'feel' for what is
going on here. Always nice to be right first time though- any advice
welcome!

> Gecko 201? About 100 $ see www.geckodrive.com
> 8 amps, very good.
>
> There are no restriction on using 2a bipolar chopper drives w.

nema23

> motors.
> The amps you can drive determine your torque.
> The volts determine your maximum speed & acceleration.

Thanks for that insight- these are just the kind of things I am
trying to figure out.

>
> What drives have you found ?
> There are very many drivers on the market, what is your main

concern/goal ?

> Cost ? Reliability ? Support ?
> A kit you solder ?
> It may help if you let us know what motors You have found.
> Of real interest, the most useful thing about them, is to know
> their speed/torque curve, nominal volts and inductance.

At the moment, cost is the big issue. I am also keen to solder up
my own drivers so I learn more about them as I go-

I have no motors yet.

Here are the two free circuits i found:

http://www.timeguy.com/cradek/cnc/stepper-drivers

and

here http://hans-w.com/modular_cnc.htm

>
> Ideally, you want motors that have maximum torque and speed in rpm.
> If possible, you should use motors that go to 1000-2000 rpm.
> A motor that will spin at 2000 rpm will be very much better.
> The difference may well be five-fold or more.

Thanks again for the great information. Those steppers you offered
for sale do sound good- I sent you an email regarding them- did you
get it?

Stefan