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Author Topic: mach3 turn - changing front/rear post wrong offset  (Read 2745 times)

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Offline nik

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mach3 turn - changing front/rear post wrong offset
« on: April 08, 2012, 02:10:21 PM »
Im I something wrong? it looks like when I change front/rear tool post something wrong is going on with the offset
when I set tools from front post only - working
when I set tools from rear post only - working
BUT when I change front and rear post - something terribly wrong happened

the only way I found to change front and rear is to change first to a tool with zero offset from front post, then to a tool with zero offset from rear post, and then I can use tools from rear post, then to go back to front post I have to change tools with zero offset in opposite way
why is that ?!?

Offline Hood

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Re: mach3 turn - changing front/rear post wrong offset
« Reply #1 on: April 08, 2012, 02:16:22 PM »
You must keep the tools set as either front or rear, you can not have a combination of both I am afraid. It is one of the many things that are wrong in turn and according to Brian not possible to fix in Mach3 but should be addressed in Mach4.
Hood

Offline nik

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Re: mach3 turn - changing front/rear post wrong offset
« Reply #2 on: April 08, 2012, 02:29:16 PM »
too bad....
it looks like the way I explained (not sure if anybody can understand me) it is changing properly, not sure yet, but I wasted too much time to find out what is going on
but if still not working properly then I cant use mach3 for my lathe too.... I have tolls on front and rear
anyway, just wondered if Im doing something wrong or this is another bug
thanks for your reply

Offline Hood

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Re: mach3 turn - changing front/rear post wrong offset
« Reply #3 on: April 08, 2012, 03:14:10 PM »
I think Homing also works but I prefer not to do things like that.
I had a front turret and also a rear turret. As my rear turret was default then I just used Rear tools in the  tool table and set the offsets up accordingly. Worked ok but you just had to use negative values for X when using tools in the front. In code that did not have negative X values I inserted a G51X-2 before a front tool and G50 to cancel, was a pain but it did work until you forgot to cancel before a tool change ;D
 I then got Dolphin CADCAM and made a custom PP for it, the X values were correct for any code it produced.

As for not being aboe to use Mach, well I think EMC is similar in that respect or at least it was what I was told when I enquired regarding front/rear tools, I was told just programme neg x values where appropriate. As that was the same as Mach there was no benefit to change.
Hood

Offline nik

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Re: mach3 turn - changing front/rear post wrong offset
« Reply #4 on: April 08, 2012, 04:38:17 PM »
the G code will be relatively simple, few tools used but few seconds each, so Im not going to use any CAM software, I will write my own G code, I tried EMC on my mill, much better, may be I have to try it for the lathe too, but very busy now, may be another day

G51 is also idea, but I didnt write any G code in the last 15 years and it is still hard to make it work with all tool offsets and orientations and front , rear, and few bugs messing around just to make it more difficult

Offline Hood

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Re: mach3 turn - changing front/rear post wrong offset
« Reply #5 on: April 08, 2012, 05:03:03 PM »
If hand coding then easy enough to do with any method, whether that be your call a dummy tool or homing or setting all up as front or rear exclusively and coding for +ve and -Ve X values as needed or even using the G51.


Hood