Re: [CAD_CAM_EDM_DRO] Bridgeport CNC Mill???

On Wed, 05 Oct 2011 11:13:53 -0500, you wrote:

>Steve Blackmore wrote:
>> I've asked several, none would use Mach or EMC in a production turning
>> environment. Mach mainly because of it's lack of servo support and
>> positional feedback, EMC because of the lack of a usable feed hold and a
>> lack of expertise or desire to tailor the software to work like a
>> commercial control.
>>
>EMC certainly DOES have feed hold, and feedrate override, these have
>been there forever.

The lack of jog in feed hold makes it all but useless. All it does it
stop the feed, nothing more, doesn't give any other options. What use is
that?

All the commercial controls I am aware of allow jog in feed hold, in the
turning shops it's used frequently, mainly to clear swarf and
occasionally change an insert.

There are proviso's even with Fanuc controls, no feed hold in some
cycles (like mid thread) and in sub routines, but that's no great
shakes. As for how it's implemented read Smid, or the relevant control
operators manual. None I know of use subroutines anyway, they have no
advantages, other than shortening the length of the code and as there is
effectively no limit, they are ignored.

>The one thing EMC does lack is extremely easy backup and re-run from a
>couple lines
>above. The procedure to perhaps change a tool, touch off and then
>restart from a
>specific line is more cumbersome (but also much less error-prone) than
>on other
>programs. (I know about the error prone from my Allen-Bradley days,
>when I would
>try to back up a couple lines where it was in the wrong mode, and get a
>cryptic
>error message. EMC2 re-runs the program from the beginning to make sure all
>modal parameters are right, but suppresses motion until the line before
>the line
>you asked it to restart at. That ensures that the tool is at the right
>position to
>commence the desired move.

Mach has the advantage there, you can jog, stop/start spindle, touch off
etc in feed hold, then resume and it will move to where it stopped and
continue. You just have to be careful where you are as it does a direct
move and you need to manually restart spindle and coolant if you turned
them off.

It also runs all the way through on a "start from" line x.

Steve Blackmore
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