Re: [CAD_CAM_EDM_DRO] Re: My dream! - Torque

Okay,

I'll toss in my $.02.

My router is a gantry type router (48" x 32" x 8" travel). It is made of
3/4" Birch ply (except the z is made from .25 aluminum plate). I use Hobby
CNC 4 axis chopper board. The X axis drives the gantry with a 190 oz, nema
23 stepper with a 1/2" lead screw from McMaster Carr, 2 turns per inch. I
can G0 at 100+ IPM with no lost steps. The y and z motors are 125 oz nema 23
and can rapid just as fast with 1" per rev travel. The X runs on liner ball
slides from ebay. The y is on 1/2" ball rails from ebay. The Z runs on a
20cm linear rail, again from ebay.

I cut mostly light foam, so the cutting forces are no that great. I do some
carving in hardwoods and it does fine. I don't need any faster movement or
more cutting power. 125oz steppers work fine with a properly designed and
built machine.

Just my $.02.
Mike Hammel
www.fancyfoam.com
1704 Bullard
Arkansas City, KS
67005

----- Original Message -----
From: "Paul" <paul3507@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Monday, June 28, 2004 6:54 AM
Subject: [CAD_CAM_EDM_DRO] Re: My dream! - Torque


> Gerry, Jan
>
> Thanks - is there some kind of formula that links torque and X-Y
> size? Or is the weight (inertia) of the moving carriage the issue?
>
> Using force = mass x accelaration My conclusion is the heaviest
> object must have enough accelaration from rest to move the step
> distance before the next pulse. The solution then is light carriage
> or big motor or slow pulses when ramping up to full speed. Am I
> right?
>
> After measuring my shed an XY size of 2ft x 3ft (or maybe 2ft x 2ft)
> is more realistic than 1m x 1m. Would 110 oz motors then be
> sensible - if not what is the max size/weight for 110oz motors?
>
> And if later I added encoders and a PIC, surely smaller steppers
> would be ok because the PIC would adjust for lost steps?
>
> Many thanks for answering these beginner questions!
>
> -Paul
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "notoneleft" <ger21@c...>
> wrote:
> > Yeah, like Jan says, I'd go for ACME or metric trapezoidal, and at
> > least 250 oz-in motors, 400 if you want to go fast. But fast costs
> $$$
> >
> > Gerry
> >
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, JanRwl@A... wrote:
> > > In a message dated 6/26/2004 11:06:03 AM Central Standard Time,
> > > paul3507@b... writes:
> > > What have I missed apart from a few weekends of work?
> > > Paul:
> > >
> > > The size of X-Y you ponder, with "V-thread" lead-screws, even IF
> > stainless,
> > > will require MUCH more stepper-motor than 110 oz-in! Even if
> you
> > were
> > > pondering preloaded ball-screws, I'd go for more like 400 oz.in.
> > per axis!
> > >
> > > Further, your best bet is "bipolar chopper".
> > >
> > > Which is less expensive, GOOD stuff that WORKS, or "surplus
> > leftovers" that
> > > won't function in the intended purpose?
> > >
> > > Lotsa luck! Jan Rowland
> > >
> > >
> > > [Non-text portions of this message have been removed]
>
>
>
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