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Tool plunges into project too deep
« on: June 04, 2017, 10:25:38 PM »
Hi.
I have a chinese 6040 machine (new). Previously I have been using a Monmus home made machine which has never given the problem I face now so I am guessing the issue may be the machine not the Vectric file I created.
Simply put, after setting the project coordinates to the top of the workpiece to cut a pocket at 3mm passes, The tool plunges deeply into the wood in a vicious attempt to bury itself.
Anybody got any answers or good suggestions?

Offline Tweakie.CNC

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Re: Tool plunges into project too deep
« Reply #1 on: June 05, 2017, 01:20:35 AM »
If you zip and post your Gcode file then that can be checked and at least rule out one possibility.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Tool plunges into project too deep
« Reply #2 on: June 05, 2017, 03:24:17 AM »
Here is my attempt to attach the gcode text.

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Re: Tool plunges into project too deep
« Reply #3 on: June 05, 2017, 03:52:34 AM »
As you suspected, there is nothing wrong with your Gcode - it runs just fine here.

Check that your cutter is secure in it's collet and not moving.

When the problem occurs stop the work and check your Z zero position.
If Z zero is now below the work surface a likely cause is loosing steps on the +Z travel - try reducing your Z axis Velocity and Acceleration settings in Motor Tuning by 50%, save the changes. Then, does the problem still exist ?

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Tool plunges into project too deep
« Reply #4 on: June 05, 2017, 05:24:12 AM »
Thanks for that. However, the tool plunges maybe 20mm into the wood although I have not measured that exactly. It is considerable and not marginal which would suggest that is is more than a few steps. The collet is always tight when I undo the buried tool.
This is an extraordinary event in my experience and it keeps doing it even with another file I tried (without the tool).
It's very easy to tell when a tool is supposed to skim the surface of the wood but the Z goes deep sea fishing something is very wrong!
Re: Tool plunges into project too deep
« Reply #5 on: June 05, 2017, 08:13:06 AM »
Hi,
couldn't be as simple as inch vs mm units could it? Try MDIing 1 unit and see how far it actually moves.

Craig
My wife left with my best friend...
     and I miss him!
Re: Tool plunges into project too deep
« Reply #6 on: June 05, 2017, 05:11:39 PM »
I set the steps per unit before, using the in-built facility in the settings tab so I know it moves accurately.
I am beginning to think it must be mechanical because I banged the Z into the top of the run a couple of times before I set my home switches properly. I will unscrew some things and see.
I may be wasting your time here because I can't see that it is a Mach 3 issue.
I will also post on the CNC forum and ask there.
Thanks.
Re: Tool plunges into project too deep
« Reply #7 on: June 06, 2017, 04:43:28 AM »
Hi,
are you sure, I know you've set things as before and/or used the built in facility but how do you KNOW it right?

Set the machine couple of inches above the table, zero Z, MDI G1 Z1.....How far does it move? Simple and a sure test of what 1 unit
is on your machine.

Craig

My wife left with my best friend...
     and I miss him!
Re: Tool plunges into project too deep
« Reply #8 on: June 06, 2017, 06:39:05 AM »
Thanks Craig
I'll try it tomorrow when I get to my workshop.
Having never used the MDI before can you explain what those commands mean?
G1?
Z1 I presume means it moves one unit... e.g. in my case 1mm?
Peter
Re: Tool plunges into project too deep
« Reply #9 on: June 06, 2017, 02:50:15 PM »
Hi Peter,
G1 means 'co-ordinated linear move at feedrate'.

Being able to read and write simple Gcode fragments is a required skill of CNCing. There are plenty of Gcode tutorials online,
observing the code generated by wizards loaded in Mach3 are valuable learning resources.

'CNC Programming Handbook' by Peter Smid is pretty much the bible as far as we are concerned.

Learning new things is a consequence of and major benefit of our hobby.

Craig
My wife left with my best friend...
     and I miss him!