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Mach3 G54 Zeroing in Negitive direction
Hi All, especially the seasoned CNCers,
I have A home build Grizzly Mini Mill with Gecko controller and Mach3 software. All was going well until I started using G59 to set tool Offset and G54 to set Work Offsets X + Gage, Y + Gage and Z + Gage. I presently am using a Non inverting X, and inverting Y and a Non-inverting Z port/pin setting in Mach3.
Background:
When I press the "Page Down" button, the Head goes towards the table. I think this is correct as Mach3 Zeros the Z axis.
When I press the "Left Arrow" button, the table goes in the Left or -X direction. I think this is also correct as Mach3 zeros the X axis.
When I press the "Up Arrow" button, the table goes in the +Y direction (into the Head). I think this is correct as Mach3 zeros the Y axis.
If this is not correct or what you use, Please respond with correction!
Here is my problem:
When I push "REF ALL HOME", the mill goes to (0,0,0) correctly.
When I set a G59 X,Y and Z, X is set to Some value, Y is set to some value and Z is set to some value (depends on when Tool Touch off is located). I save Work Offsets (or think I do) and exit Mach3. The values are lost and must be redone each time (Contrary to what I read on the screens which says "Make them permanent").
So I don't exit Mach3.
Instead, I set Part X to Gage thickness + X in the most Left position with work on the RIGHT (positive X direction). I believe the is X0 + Gage and G54 X is set to Gage thickness.
Next, I set Part Y to the closest to Y zero position with the work in the direction of +Y. I believe this is Y0 + Gage position.
Then I set Z to Top of Part + Gage.
At this point X = 0.0632, Y = 0.0632 and Z= 0.0016.
All looks great to me. At this point I save both Work Offset and Tool Offsets as I think they are correct. I then go to MIDI tab and enter "G0G90G54X0Y0" and the table moves in the -X and -Y direction by the value in G54 table (-0.0632, -0.0632) which doubles the offset to -0.125, -0.125. Very aggravating.
This is where I need help! The table should go to (0, 0) but instead goes to ( -0.125, -0.125). THIS IS MY PROBLEM!
Other information:
I have used the Port Pin assignment to invert the X and Y Direction. When I do this, the Mill zeros the part correctly but the Mill goes in the wrong direction to Reff All Home so is incorrectly set up.
Really need help so I've attached my NC file and my BobCAD-CAM Pat file.The attached file Grizzly... No-ATC is the BobCAD-CAM file and the Presentation... file the result nc file for Mach3.
I don't know if the values are off for the NC file and that isn't really an issue, I just included them for completeness.
Re: Mach3 G54 Zeroing in Negitive direction
Quote:
When I press the "Left Arrow" button, the table goes in the Left or -X direction. I think this is also correct as Mach3 zeros the X axis.
When I press the "Up Arrow" button, the table goes in the +Y direction (into the Head). I think this is correct as Mach3 zeros the Y axis.
These are backwards. The jog arrows should be the tool movement, not the table movement.
Left Arrow would be the tool moving left, with the X axis DRO counting down. (Table moving Right)
Up Arrow would be the tool moving back, with the Y axis DRO counting up. (Table moving towards you.)
Re: Mach3 G54 Zeroing in Negitive direction
Are you confusing absolute coordinates with work offsets? When you go to the stock and set G54 (or G59, 58, 56, 57, 55) you should zero X,Y,Z. Your CAM work offset 0 is usually something you can reference on the stock. When you go to a second part you would then use G55 and up. The machine absolute coordinates are whatever, your program reads your work offsets. So that small error you are seeing seems to be related to absolute coordinates to me. 0,0,0 is not established for G54 after reference, you establish G54 at the stock. A wobbler or touch probe is used for this. Absolute coordinates are relevant, but not to what you are doing. If you set work offsets to zero, even if your machine is moving in the wrong direction (Ger is right), the machine will still go to 0,0,0 and start machining, though it may head the wrong way off the stock.
You can also change your homing direction under the config. So get your arrows working as Ger says. Then in the homing menu you can change which way it homes, it's really up to you which way it homes/references. I like my table to home Y+ and X- with the Z at near maximum Z+. Why? It makes it easy to change fixtures, fixture parts, and changes tools after it's referenced (and homed because my machine does both in that op). Lot's of people like to home/reference in different ways, manual machinists generally like their table to be at X center and Y center.
Re: Mach3 G54 Zeroing in Negitive direction
Quote:
Originally Posted by
CL_MotoTech
Are you confusing absolute coordinates with work offsets? When you go to the stock and set G54 (or G59, 58, 56, 57, 55) you should zero X,Y,Z. Your CAM work offset 0 is usually something you can reference on the stock. When you go to a second part you would then use G55 and up. The machine absolute coordinates are whatever, your program reads your work offsets. So that small error you are seeing seems to be related to absolute coordinates to me. 0,0,0 is not established for G54 after reference, you establish G54 at the stock. A wobbler or touch probe is used for this. Absolute coordinates are relevant, but not to what you are doing. If you set work offsets to zero, even if your machine is moving in the wrong direction (Ger is right), the machine will still go to 0,0,0 and start machining, though it may head the wrong way off the stock.
You can also change your homing direction under the config. So get your arrows working as Ger says. Then in the homing menu you can change which way it homes, it's really up to you which way it homes/references. I like my table to home Y+ and X- with the Z at near maximum Z+. Why? It makes it easy to change fixtures, fixture parts, and changes tools after it's referenced (and homed because my machine does both in that op). Lot's of people like to home/reference in different ways, manual machinists generally like their table to be at X center and Y center.
Nope, not confusing absolute or machine offsets with Work Offsets. As Ger said, my X movement and Y movement was set backwards or in the wrong direction.
I changed the direction and ran the .nc file in air cut and it looks good. At present I no longer have X-Home and Y-Home limit switches but they are on order.
I ran a dirty X,Y,Z home this morning and everything looks good. A few days of work and I'm good to go.
Thank you for your thoughtful reply.
CES
Re: Mach3 G54 Zeroing in Negitive direction
Just home to your XYZ limits.
