Daniel Goller wrote:
> So what we can avoid is the turret hitting the chuck and the turret
> hitting the tailstock 
>   
One possible fix for this is to install a guard plate that wraps around 
the tailstock
at places where it could be hit by the carriage or turret.  This would 
be spring-loaded,
and have a microswitch connected to the E-stop chain.  If anything ever 
hits the
plate hard enough to push it in, it E-stops the machine.  The springs 
need to be stiff
enough that chips and coolant splashing won't trip the switch.  This 
avoids the
problem of knowing where a movable part (tailstock) is positioned, and 
solving
complex interference calculations.

This scheme won't work for the chuck, however.  I think a software 
solution is
about the only one that can solve that problem.  it gets even trickier 
as it matters
whether the jaws are extended for a big part or fully inside the chuck 
body, and
also what is mounted where on the turret.
>
> Machines with a 2nd turret are then kept from the turrets crashing
> into each other by proper programming of the two turrets alone, or can
> you check if W is at a certain location (or home) before running X
> into the 2nd turret?
>   
Some of this could be implemented in ClassicLadder or Hal, since all 
turret operations
are handled through them already.  Varying the clearance for one axis 
based on position
of another is not something that is immediately available in EMC at the 
interpreter level
(where soft limits are handled now, I think).  But, you could still 
implement a HAL scheme
that watches current position and causes an E-stop when certain rules 
are violated.  You'd
probably want to have PyVCP running  so it could provide specific 
warning messages explaining
what happened.  It might be most efficient for a real exclusion area 
program to be written as a C program
and implemented as a Hal component.  It would receive X and Z actual 
machine position, and
feed into the E-stop logic.   Hmmm, than you'd need to rig an override 
scheme to back out of the
exclusion zone when it crashed.  Clearly not as optimal as detecting it 
before starting the program.

You could clearly set up a test system to detect these, too.  It could 
either be a sim version of
EMC, or built into a preview program. 

Jon

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