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Z Axis problem
« on: May 29, 2014, 01:48:04 AM »
Hi
I’m new here & new to CNC machines. Some background:
•   I have a homemade machine. The working area is approx. 2’ x 4’ with 4” of travel on the Z axis.
•   I have ½” lead screws on all axes – 2 to 1.
•   The motors are NEMA 24 for the Y & Z axis; NEMA 34 for the X axis.
•   I am using Windows XP with Mach 3
•   The projects I am trying to cut were done on Cut 2D 1.5.
•   Right now I’m just doing simple tests such as a name plate where the letters are cut out by the machine.
•    The material I’m cutting is wood – 5” x 10”, 5/8” thick is typical. I use the bottom left corner as my X,Y origin point.

The problem I’m having is that when I start cutting the project, the CNC machine lowers the tool all the way through the work piece and actually into the table (about .02”) & stays there until it reaches the start point of the 1st letter to be cut. The machine then raises the tool & starts cutting the letters. However, it regularly lowers the tool below the bottom of the cut I want to make. It does this in between letters. Then, at the end of the cut, the bit gets lowered all the way through the piece & it stays there until it reaches the start point.
The physical set up of my machine looks OK. I’m wondering if I set up Mach 3 wrong.
Hope this is the right place to post this. If not, any suggestions as to where I can get help would be appreciated.
Thanks,
Bob

Offline Tweakie.CNC

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Re: Z Axis problem
« Reply #1 on: May 29, 2014, 06:50:57 AM »
Hi Bob,

My guess is that you have your settings wrong in Cut2D.
If you .zip and attach your GCode file I will check it here and see if it is OK.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Z Axis problem
« Reply #2 on: May 29, 2014, 07:15:57 AM »
Tweakie,

Thanks for looking at this! Zip file is attached.

Bob

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Re: Z Axis problem
« Reply #3 on: May 29, 2014, 07:56:56 AM »
Hi Bob,

Your GCode plays out fine here so nothing wrong with your Cut2D settings as I had suspected.

Perhaps look in Mach3 / Config / Safe_Z Setup – if the Allow Safe_Z Moves box is checked then uncheck it (or alternately if you wish to use Safe_Z then make sure all the settings are correct).

Perhaps stupid suggestion but is your machine’s Z axis configured correctly with Z0.200 moving the spindle upwards and Z-0.0500 moving it downwards ?

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Z Axis problem
« Reply #4 on: June 04, 2014, 12:51:58 AM »
Tweakie,

Thanks for your help with my problem.

Your suggestion was not stupid; I has my Z Axis set up incorrectly. It just took me a while to see & fix it! My machine seems to be running fine now.

Again thanks for your help.

Bob

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Re: Z Axis problem
« Reply #5 on: June 04, 2014, 01:47:37 AM »
Hi Bob,

I am pleased to hear that you have resolved the problem  ;)

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.