Re: [CAD_CAM_EDM_DRO] Digitizing arm?

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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