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Lathe tool offsets / strange movement ?
« on: December 06, 2009, 04:33:38 PM »
Hello,
 
I'm running Mach3 version R3.42.32 and I am having difficulty with tool changes.
The issue is I'm seeing a 'spurious' motion in the X axis following a tool change command, say T0303 ( Other tool number selection do similar things)
 
For example -
The starting position for the tool is X0 Z15.
When the program is run the X axis moves 3.96mm towards in a minus direction ( the tool3 offset is x-3.96  Z 12.17)
 
If the X tool offset is positive the tool moves out in the positive direction. 
 
If I remove the G00 X0 command at line N40, so there is no reference to any X move in the program at all, the X axis still moves following the T0303 at line 20. And because there's now no X move, each time the program is run the X moves progressively in the same direction.
I would appreciate any insight as to what I'm doing wrong.
 
Cheers Derek,
 
 
%
N10 G00 G18 G21 G40 G50 G64 G80 G90 G94
N20 T0303
N30 M3 S750
N40 G00 X0
N50 G00 Z0
N60 M5
N70 G00 Z15
N80 M30
%
 

(Tool 3 x offset -3.96  Z 12.17 )
You can "chop it off" but can't "chop it on"

Offline Hood

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Re: Lathe tool offsets / strange movement ?
« Reply #1 on: December 06, 2009, 05:19:17 PM »
On my lathe nothing will move unless commanded, if I change a tool number the DRO's will change to reflect the offsets  but no motion will occur until commanded.
What is in your M6 macro?
Hood

Offline Graham Waterworth

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Re: Lathe tool offsets / strange movement ?
« Reply #2 on: December 06, 2009, 06:40:19 PM »
what happens if you change your code to this :-

%
N10 G00 G18 G21 G40 G50 G64 G80 G90 G94
N20 T0300
N30 M3 S750
N40 G00 X0 T0303
N50 G00 Z0
N60 M5
N70 G00 Z15
T0300
N80 M30
%

Graham
Without engineers the world stops
Re: Lathe tool offsets / strange movement ?
« Reply #3 on: December 07, 2009, 03:20:54 PM »
Hi Graham,

Thanks for your reply.

Now when I run the program with your  mods it does the following.
Initial set up with tool 0 and x set to 0.

Cycle Start to run program -
'Press cycle start after tool change' line 20 - DRO X=0
'Press cycle start after tool change' line 40 - X moves to X=7.95   DRO X=+7.95
Once cycle start is pressed X axis moves to X=0 and X=0 shown on DRO
Z moves to Z=0
Spindle stops
Z moves to Z=15
At T0300  X DRO = -7.933
Press cycle start X moves, X DRO = -3.96

Second time and subsequent runs of the program the X readings are slightly different.
Cycle Start to run program -
DRO X=-3.96
'Press cycle start after tool change' line 20 - X moves to X=-1.98 DRO X=-1.98
'Press cycle start after tool change' line 40 -Xmoves to X7.95  DRO X=7.94
Once cycle start is pressed  X axis moves to X=0
Z moves to Z=0
Spindle stops
Z moves to Z=15
At T0300  X DRO = -7.933
Press cycle start X moves, X DRO = -3.96


I hope you can help !  I'm lost with this one.



Hi Hood, 

The M6Start.m1s macro has this -

tool = GetSelectedTool()
SetCurrentTool( tool )


Cheers,
Derek.


what happens if you change your code to this :-
Graham
You can "chop it off" but can't "chop it on"

Offline Graham Waterworth

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Re: Lathe tool offsets / strange movement ?
« Reply #4 on: December 08, 2009, 12:03:15 PM »
Has your machine got homing switches fitted?

If you have homing, what are the figures in the x and z dro after homing?

What figures do you have in your tool offset table for tool 3?

Are you working diameter or radius?

Is X zero on the centre line of the spindle and Z zero on the front face of the work?

Graham
Without engineers the world stops
Re: Lathe tool offsets / strange movement ?
« Reply #5 on: December 08, 2009, 02:35:51 PM »
Hi Graham,

No homing switches are fitted to the machine.
The offset table for Tool 3 is  X-3.9697  Z12.1729   Post is set to front.  All other settings are Zero.
I'm set to run in diameter mode.
X=0 on the centre line of the lathe and Z=0 on the face of the work.

Cheers,
Derek.


Has your machine got homing switches fitted?
If you have homing, what are the figures in the x and z dro after homing?
What figures do you have in your tool offset table for tool 3?
Are you working diameter or radius?
Is X zero on the centre line of the spindle and Z zero on the front face of the work?
Graham

You can "chop it off" but can't "chop it on"
Re: Lathe tool offsets / strange movement ?
« Reply #6 on: December 28, 2009, 11:04:21 AM »
Hello,

I hope everyone has had a good Christmas and looking forward to a Happy New Year.

Over the break I've been looking in to why I get an unexpected X movement following a tool change. It's still doing this and I've still not being able to eliminate it.
The program below should not make any X movement  unless I've missed some thing !
Hopefully the following description will give some one a clue to what to look for.

I loaded the following program
%
N10 G00 G18 G21 G40 G50 G64 G80 G90 G94
N20 T0101
N30 G0 Z0
N40 G0 Z10
N50 M30
%

Tool 1 has tool offset of X+2.0 Z+10.0
I initially position the machine to read X0 Z0 with Tool 0 selected.

The following happens when the program is run first time through using single step, clicking on cycle start to execute each line.

At line N20 the DRO changes from X0 Z0 to X-4.0 Z-10.0 at the T0101 command  - OK
At line N30 the X axis moves to X0 when clicking cycle start and then the Z moves to Z0 on a second click on the same line N30.  (Why does the X move on this line?)
The remaining lines moves Z to zero and Z back to +10 as expected.
The program stops with the DRO X0,Z+10

However when the program is run again from this finishing position the X axis moves to X+2.0 at line N20
and the program finishes with the DRO shows X2.0 Z10

Subsequent runs through the program move the X axis in smaller + steps with the DRO displaying the following coordinates when the program finishes.
X2.99 Z+10
X3.49 Z+10
X3.74 Z+10
X3.87 Z+10
X3.92 Z+10
X3.95 Z+10
X3.97 Z+10
X3.99 Z+10

When X reaches 3.99 no further X movement is seen when the program is run.


If I change the tool offset for tool 1 to X+5.0 Z+10 a similar thing happens but the X axis finishes at X+9.99 after 10 or so runs of the program.

If the tool offset is negative, say X-5.0 the same movements happen just in the opposite direction.

And finally if I switch to radius mode in Config>Ports & Pins>TurnOptions
the X movement continues in steps of the same size and direction as the X tool offset value, until a end limit would be hit.

If any one can offer any suggestions or tests I should make I would be very gratefull.

All the best
Derek. 
You can "chop it off" but can't "chop it on"

Offline Hood

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Re: Lathe tool offsets / strange movement ?
« Reply #7 on: December 28, 2009, 11:34:20 AM »
Zip your xml and the macro folder for your lathes profile and also any Brains you use and attach and I will see if I can replicate here.
Hood
Re: Lathe tool offsets / strange movement ?
« Reply #8 on: December 29, 2009, 06:36:59 AM »
Hi Hood,
Thank you for helping.
The .xml and macro directories are in the attached .zip
I'm not using any Brains but I've included the directory just in case.
Cheers,
Derek.

Zip your xml and the macro folder for your lathes profile and also any Brains you use and attach and I will see if I can replicate here.
Hood
You can "chop it off" but can't "chop it on"

Offline Hood

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Re: Lathe tool offsets / strange movement ?
« Reply #9 on: December 29, 2009, 07:34:08 AM »
Your M6 End macro looks like the culprit at first glance, just downloaded this second and not had a chance to try but as far as I am aware the M6End macro for turn should not have anything in it or at least the standard one has
REM nothing here in lathe

which in effect is a comment telling you there is nothing in it ;D

Hood