Re: [CAD_CAM_EDM_DRO] Re: stepper & driver

Hi Bellendo
I will take your advice on the two motors driving the x axis and will
use instead a jack shaft to drive sprockets on both sides of the x axis and
will use chain on the Y axis as well.
I will be making parts during the winter as well as finishing up my
building. Assembly will start in the spring.
In the meantime I will also build a very small three axis
engraver-router to learn what the building of a cnc machine is all about. I
have some small stepper motors and an old 486 Dell computer to run it. and a
bunch of shafting out old dot matrix printers too. I don't want to reinvent
the wheel on this so I will probably buy a set of plans to work from. Any
advice as to what set of plans would be easy to build using as much of the
hardware that I have would br helpful.
I would like to thank you and everyone else for their input.
Doug

- Original Message -----
From: "ballendo" <ballendo@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Wednesday, November 26, 2003 3:29 AM
Subject: [CAD_CAM_EDM_DRO] Re: stepper & driver

> Doug,
>
> Sounds like you've considered the implications of the Oak subframe,
> and it will likely work since you're willing to sacrifice some
> accuracy.
>
> I personally don't think using two motors on a given axis is a good
> idea... (Mariss of Gecko has also stated the problems of such a
> choice.)
>
> Having said that, there are a large number of machines both hobby and
> commercial which successfully use two motor drive. But I wouldn't...
>
> If you're going to use chain for the long axis (X, though some
> mistakenly call this Y); IMO you should also use it for Y. You will
> get FAR in excess of your desired travel rates, IME. Easily 240 IPM
> with 2A "cheap" drives, 34V power, size 34 double stack motor, and
> 4:1 reduction. For cuts in the 120IPM arena... BTW, go ahead and use
> a screw for the Z, it makes things easier.
>
> Good luck, send pics when you're done!
>
> Ballendo
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Douglas Pollard"
> <dougpol1@o...> wrote:
> > Hi cnc folks,
> > My thinking on using oak to build a cnc router is that I
> already have the wood "free". with it screwed and glued together it
> will be light. Several coats of epoxy will solve most of the
> expansion problems where moisture is concerned. I plan to use metal
> ways for accuracy and ease of movement. The x axis rails will be
> tied together with metal bars so the expansion of the wood will not
> change the y axis width. Only one rail will be bolted tight to the
> wood the second will offer support only but will not act as a guide.
> > I have 50 ft of roller chain it is about the size of bicycle
> chain # 10 I would guess. I am thinking that I will put one piece on
> each side of the gantry to drive in the x axis. Each side will be
> driven by a # 33 frame motor {Ithink this is the right designation?}
> It's close anyway. I understand that. I that I can hook them up in
> series.
> > I would consider 30 to 50 inches a min. feed rate with 100
> inches rapid traverse a complete success anything faster would be a
> bonus.
> > The Y and x axis would probably be driven by lead screw. I
> see no reason that a second motor on the y lead screw could not be
> added if needed also hooked up in series.
> > Any comments on the practicality of hooking motors in
> series would be a big help. Do you get double the power? Do they
> interfere with each other? Does this overload the drivers in some
> way. I assume power supplies have to be larger?
> > I have seen reference to this practice on line but no real
> detail as to, how.
> > Doug
>
>
>
>
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