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Trouble with tool changes...
« on: February 24, 2009, 10:44:16 AM »
I am having unpredictable results using the "Tool Change" feature. I have an X/Y plotter which emulates our lathe. I use this device to work out cutting paths to scale before applying the G-Code to the actual lathe.

Tool #1 is a pointed tool in the front tool post with an X-Offset of 0.0 and a Z-Offset of 0.0.  (ignoring tool #2...)  Tool #3 is also a pointed tool, with a front/rear tool post distance of -1.0 and a Z-Offset of -1.0... The small offset is to keep the trace on the paper.

I load in a test G-Code profile which I have written. The plot begins with tool #1 and the tool path is drawn exactly as I have entered. Then a tool change (T1301) is executed and the plotter goes bezerk. The pen runs off the paper and I have to stop the stepper motors on the plotter to prevent a collision. When the plot completes (returning to 0/0) and I look at the settings for Tool #1, Tool #1 is exactly as I set it.  Tool #3, however... the settings for the Z-Offset have changed radically.

Put the tool settings back the way they were, and at the moment when the change to tool #3 is executed, the plotter goes bezerk again,  Z-Offset for tool #3 ends getting changed again... this time, sometimes by a different amount.  Also, if I pause the process while Tool #3 is active The Z-Axis Jog is backwards from what it should be. Select Tool #1 manually, and the Z-Axis jog returns to normal.

N100 T0101                           %(Tool Change)
N110 M3                              %(Start Spindle)
N120 G0  Z0.0    X20.0
N320 G01 Z0.0    X16.7        F150.0 %(Ready to begin the curves)
N330 G01 Z-0.01  X16.7        F150.0
N340 G03 Z-14.1  X15.5 R9.4   F150.0 %(Cut the curve)
N350 G01 Z-14.1  X14.5        F150.0 %(Short straight before back curve)
N360 G02 Z-18.1  X10.4 R3.9   F150.0 %(Back Curve)
N400 G01 Z-28.1  X10.4        F150.0
N405 G01 Z-28.1  X12.0        F150.0
N410 G01 Z-36.3  X12.0        F150.0
N420 G01 Z-36.3  X10.4        F150.0
N430 G01 Z-38.6  X10.4        F150.0
N435 T0301                           %(Tool Change)
N436 G04 P1000
N440 G01 Z-38.6  X10.4        F150.0
N450 T0101
N460 G01 Z-38.6  X10.4        F150.0
N470 G0  Z-38.6  X20.0       
N480 G0  Z0.0    X20.0
N490 G0  Z0.0    X0.0

Offline poppabear

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Re: Trouble with tool changes...
« Reply #1 on: February 24, 2009, 10:51:32 AM »
you have : (T1301)

change it to T1313  Keep your hiegth offsets that belong to that tool WITH that tool. See if that helps you, Set the XZ tool offset for each tool individually.
I know Turn says you can use another tools offset with a different T#, but as you have found it can be buggy to do so.

scott
Commercial Mach3 & Mach 4, Design/Build/Retrofit CNC and Industrial machines.
http://www.ss-systems-llc.com/
Re: Trouble with tool changes...
« Reply #2 on: February 24, 2009, 04:08:42 PM »
If my front tool (T0101) has an X-offset of 0.0  and a Z-offset of 0.0...
my front/rear  toolpost offset is -1.0
and my rear (T0303) tool has av X-offset of -1.0 and a Z-offset of 0.0
When I change from T0101 to T0303, shouldn't the shuttle mov 1.0mm to the right and 1mm toward me and continus moving through G-codes with that offest until the next tool change?  Why is it that as soon as I call T0303 the plotter moves 1mm to the right and about half the width of the page toward me?

Offline Hood

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Re: Trouble with tool changes...
« Reply #3 on: February 24, 2009, 05:23:06 PM »
Are you using Turn? Are you setting some tools in the table as Front and others as rear?
If so dont, it is broken and doesnt work properly, either set all your tools as front or all as rear.
Brian is going to be working on Turn soon, well should be soon but he has been saying that for quite a while now and things in Mill keep getting in the way.
Hopefully this time he will get onto Turn and get it sorted as it is badly needing some work done.
Hood
Re: Trouble with tool changes...
« Reply #4 on: February 24, 2009, 07:17:45 PM »
Thanks Hood,  I sort of thought this was "buggy". So I simply set all me tools as "Front" get the "X-axis" to adjust using X-offsets...

Tom Mierau

Offline poppabear

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Re: Trouble with tool changes...
« Reply #5 on: February 25, 2009, 08:55:29 AM »
Also

   If it is moving only Half way towards you then your are in Radius Mode, switch it over to Diameter mode.......

scott
Commercial Mach3 & Mach 4, Design/Build/Retrofit CNC and Industrial machines.
http://www.ss-systems-llc.com/
Re: Trouble with tool changes...
« Reply #6 on: February 25, 2009, 09:34:44 AM »
Hey folks...  I got it working. Thanks for all your help!!

TunerTom

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Re: Trouble with tool changes...
« Reply #7 on: February 25, 2009, 12:43:23 PM »
so..........  What was the problem then?

scott
Commercial Mach3 & Mach 4, Design/Build/Retrofit CNC and Industrial machines.
http://www.ss-systems-llc.com/
Re: Trouble with tool changes...
« Reply #8 on: February 25, 2009, 01:10:22 PM »
The problem is that I had front & rear tools and according to Hood, he suggested that I make all my tools "Front" tools in the setup and adjust the X-Offset for the tool which is actually a "Rear" tool to get the saddle to move the appropriate distance in order to engage the rear tool. His explanation of this is listed above in this thread.