axis clamping was Re: Measuring backlash more accurately?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "ballendo <ballendo@y...>"
<ballendo@y...> wrote:

> Juha,
>

> However, the G code standard has codes for clamping and unclamping
> axes. Although Art's plate is pretty full right now, I think you
> might be able to do something in a macro (with only a "bit" of

help

> from Art). AIRC, the nist interpreter that Art has based Mach1

upon,

> included at least one axis clamp; included for an older machine

they

> were retrofitting (Ray or Matt would likely know).

Some hobby controllers support fixture clamping on mill and Chuck
jaw open and close on lathes, but few seem to have an axis clamp
specifically. It was supported in some of the older machines that
had a lead screw to move a massive head up and down, then a separate
process to program the Quill which was for the actual precision
cutting (GE550 for sure). A process similar to that used for a
seperate quill and saddle axis on a bridgeport.

Most of the hobby controllers can support either a macro (custom M
codes) subroutine, like Ahha, or in the case of DeskCNC there is a g-
code macro that runs with a tool change. This could be used to
create a customized clamping/unclamping routine.

It would be a matter then of post processing in your Cad-Cam.

There is then still the difficulty of adapting the machine hardware
to prevent motion attempts if the clamp didn't unclamp.

This closed loop gets more difficult as many stepper systems are
strictly push with limited feedback capabilites.


Fred Smith - IMService