Re: [CAD_CAM_EDM_DRO] Taig CNC Mill vs.Homebuilt Machine

Bob,

If you are building home-brew, you might consider a Stewart Platform (aka
Hexapod) mill.

I'm into construction of my third generation machine. I still haven't
gotten a head appropriate for milling steel, but I'm well fixed for
aluminum and wood. I'm waiting for LittleMachineShop.com to get a shipment
which includes an R8 head assembly

Advantages of a Stewart Platform are:
Accuracy does not depend on long, flat, straight, STONG linear ways.
All forces are compression or tension -- nearly no bending forces
are applied to moving parts.
Full six axis positioning.
Possibly lower torque requirements for motors.

Disadvantages:
Larger physical size.
Six actuators, motors, and drivers instead of three.
Accuracy comes from software and calibration rather than
mechanical craftsmanship.

-- Carl


At 03:40 AM 2/4/2003 +0000, you wrote:

>I have read with great interest many archived and all current
>postings since joining this Group. I am encouraged enough to move
>from the periphery and into the fray and would like to know whether
>there is a compelling reason to buy a mill and modify it for CAD/CAM
>use rather than assemble one from discrete components attached to a
>welded frame, whether in traditional mill form or gantry.
>I have been leaning towards building as it seems to promise larger
>than "benchtop mill" size and I have several ball screws, linear
>bearings, motors and drivers. I have believed that the use of these
>components is inherently better than leadscrew and dovetail ways in
>obtaining a tighter tolerance and longer life. My specific concern,
>however, is the linear bearing's ability to withstand repeated stress
>and my ability to construct a frame to proper tolerance.
>On the other hand, the temptation to purchase a CNC ready Taig is
>justified in my research having yet to read a single complaint or
>regret. I could even us it to build a gantry mill as my second
>machine.
>I appreciate this group and have been impressed by its contributors
>namely Les, Tim, Wes and Jan to name a few.
>Sorry Bill, is that flaming?
>
>Thanks for the consideration,
>Bob O'Neal
>

Carl Mikkelsen
cmm@...
www.foxkid.net