Re: Digitizing arm?

I have real hope for Mach3 software doing what I want. as for the
encoders I have the 5000 step units but was thinking of setting it up
for 2to1 so I would get 10k steps per 360. also looking at pic chips
to be the interface. if I was an 1/8 inch off its ok as it would be
for personal use only. once I do get it running I would work on the
accuracy. Also as this is a diy its ment to be cheap but useful for
others if they want to make one.

Don C


--- In CAD_CAM_EDM_DRO@yahoogroups.com, R Rogers <rogersmach@...>
wrote:

>
> After kicking this idea around of an articulated digitizing arm for

about 5 years, It will be a while yet before I try to persue it. This
would be a great addition to the CNC homeshop inventory. Many uses.

>
> First problem I see is deflection of components. All of the arms

parts would have to be relatively light and very rigid. The second
issue is the resolution involved with the encoders. Take the
circumference of 72" divide it by 360 and it's easy to see how coarse
even a 2000 line encoder would be. Could increase its rotation though
by planetary means. Lastly, the real obstacle to overcome would be
the software. Taking digital step and direction signals through 3 or
4 encoders and trigging out each arms angle and ultimately arriving
at the position of the stylus globally. There is a reason they get
$60k plus for these arms. And thats just a portable unit.

>
> If you need a large envelope 3 axis scanner, it could be done

with a gantry style machine. Would be alot easier. Mach3 software is
now doing 3D digitizing.

>
> Its a great idea though, Ron
>
>
>
>
>
> Don C <tekno62@...> wrote:
>
> I was wondering if anyone here is working on a digitizing arm. I

have

> read a few sites and I would like to build one. One of the reason

is I

> need a 6 foot working space. I have looked at the Microscribe
> <http://www.immersion.com/digitizer/> arm but the Microscribe has to
> small working area. I will only need a .1 accuracy if that. I have

also

> thought about laser scanning. I picked up 6 Hengstler RI 58
> <http://www.hengstler.com/gfx/file/shop/encoder/install/2-531-

069_Kurzin\

> stallationsanleitung_E_RI58-D_TD.pdf> encoders that may not be

workable

> for this project.
>
> I join this forum as one of the sites " LINK "
> <http://www.indoor.flyer.co.uk/digiarm.htm> I found talk about
> modifying a DRO program. Im hoping that someone is willing to help

me

> along with this. I just need to be pointed in the right direction

and

> hate to reinvent the wheel.
>
> Thanks
>
> Tek
>
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