Re: [CAD_CAM_EDM_DRO] Re: stepper driver help

If you want to solder up the drivers yourself, the Hobby CNC boards are
definitely a good option. I actually own 2, and steal parts from one to keep
the second one running (the parts one has two blown driver chips, but
everything else works). So far the only part I have had to replace was the
main power regulator which blew when I got a chip across its leads (I have
the boards in a good enclosure which prevents that during operation, but I
opened up the enclosure for testing my new spindle control relay and a few
chips dropped onto the board in the process).
Michael

On 9/27/07, stefan_sharpe <stefan_sharpe@...> wrote:
>
>
> > 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
>
>
>


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