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Author Topic: Something to fix for Mach 4 ??  (Read 1863 times)

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Offline Sage

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Something to fix for Mach 4 ??
« on: March 26, 2014, 10:51:38 AM »
So, here's the scenario:
I have a typical Gcode file with multiple procedures, drill a hole, mill a profile, mill a pocket etc. I do manual tool changes so I have Mach stop on tool change. So the code is halted on a the tool change line of code. No problem. Usually after changing the tool I need to move the table over to a clear piece of material surface to set the tool zero. Sometimes I also need to move clamps etc. to accommodate the upcoming procedure. Sometimes I need to move it a lot to get a screwdriver in under the head to remove a screw that was being used to hold a piece down. You name it. Still no problem.
 The problem comes when I press start after the tool change. Mach insists on returning to the position it was at when it finished the last procedure before it turns around and goes to the location spelled out in the code for the next procedure. Makes no difference if you manually put the cutter right over the position of the next procedure. It still moves back to the previous location first.
It does this at G0 speed as well. This return move is not part of the code it's just something Mach wants to do. It also does it with a combined X,Y and Z move so even if I have a proper rapid clearance for clamps etc. It can still hit clamps because it does not do the Z move first and independently.
 Sorry I can't give you any code file to replicate this because it's not in the code. It's something Mach does on it's own.
Anyone can emulate it by doing what I've described.
Stop on tool change
Move the table around while it's stopped
Leave it anywhere you like
Start the code again and see where it goes first. It will be to the last position it was at and then immediately to the position in the next line of code. No stops.

It's a bit dangerous, I think, and there is no real good reason for it (that I can see).

Sage
Re: Something to fix for Mach 4 ??
« Reply #1 on: March 26, 2014, 11:13:50 AM »
As part of your tool change procedure, perhaps you should always have the axis' move to a dedicated "Tool Change Position". It will be well clear of all parts and fixtures, no secondary manual moves necessary and the program will resume directly from there.
There are DRO's for the TCP on the Settings page.

Russ
Re: Something to fix for Mach 4 ??
« Reply #2 on: March 26, 2014, 11:18:43 AM »
It also might be a good idea for you to use a "Safe Z" to insure that the Z is up well clear of obstacles prior to the X,Y moves.

Russ

Online ger21

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Re: Something to fix for Mach 4 ??
« Reply #3 on: March 26, 2014, 11:54:36 AM »
The best thing to do is modify your M6 macros to do exactly what you want. Then you won't need to be jogging around and have to worry about Mach backtracking.
« Last Edit: March 26, 2014, 11:57:15 AM by ger21 »
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Offline Sage

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Re: Something to fix for Mach 4 ??
« Reply #4 on: March 26, 2014, 09:47:39 PM »
Russ:
Thanks I'll check out those options.

Gerry:
"Exactly what I need to do" can not be defined ahead of time. As I explained, I'm more moving the table around to get things out of the way to do things like move clamps and add / remove hold down screws. There's no way of knowing exactly where one needs to go to make clearance for a screwdriver to get in under the head (mill drill).

As Russ suggested maybe a tool change position far and away from the work area is the place to go. I assume Mach knows how to deal with and recover from that move safely.

I'll have to give it a try.

Thanks
Sage