Z Axis changes coordinates mid program

[robotek]

one of those writings in chinese says work coordinates, the other is machine coordinates. I ran other files, which were smaller, without problems, even one that i had to change a part orientation of.

[mactec54]

one of those writings in chinese says work coordinates, the other is machine coordinates. I ran other files, which were smaller, without problems, even one that i had to change a part orientation of.

Machine Coordinates is once you home the machine that is the machine Coordinate

Work coordinate is your G54 X---- Y---- Positions

Once you home your machine, these axis Home positions are the machine Coordinates X, Y and Z

Once you Home all your axis, you can then set the G54 X----- Y------ work Offset positions then your G43 Z axis Tool height Offset

What does Offset mean, this means you have set your work and Tool from the Homed Machine Coordinates some snips that may make this a little more clearer as to how it works

[robotek]

Machine Coordinates is once you home the machine that is the machine Coordinate

Work coordinate is your G54 X---- Y---- Positions

Once you home your machine, these axis Home positions are the machine Coordinates X, Y and Z

Once you Home all your axis, you can then set the G54 X----- Y------ work Offset positions then your G43 Z axis Tool height Offset

What does Offset mean, this means you have set your work and Tool from the Homed Machine Coordinates some snips that may make this a little more clearer as to how it works

Thank you. I do it in a similar manner with my controller. After homing the machine. I jog it to the part’s origin, then record and save X and Y coordinates under G54. Then, I measure the height difference between the tool probe and the parr’s origin, record it in Tool Checker settI Gs. Next, I run the tool probing routine and it offsets the tool length automatically.
The question I just got is from your snips: what is H01 in the code line?
Thanks

[mactec54]

Thank you. I do it in a similar manner with my controller. After homing the machine. I jog it to the part’s origin, then record and save X and Y coordinates under G54. Then, I measure the height difference between the tool probe and the parr’s origin, record it in Tool Checker settI Gs. Next, I run the tool probing routine and it offsets the tool length automatically.
The question I just got is from your snips: what is H01 in the code line?
Thanks

H01= Offset for T01 this is in the G43 Tool length Offset register, so whatever Tool Number you are using, it will have a G43 H04=T4 Offset Tool 4 or any number Tool you are using, does not need the zero T01=T1 same thing some controls may need it as T01

[TTalma]

Servo's don't lose steps.

Missed the part where he was using servos. I agree that's most likely not the issue

[TTalma]

That is code that you would not want to use to check your machine

I'm curious why you feel this process is bad (granted there may be an error in the code, I didn't check it). The goal was to do a bunch of motions where the machine should return to the original position. When I initially set up my machine I did something similar to get acceleration correct.

The encoder can only feedback that the motors rotated correctly. This does not mean that the movement is correct. On the commercial CNC machines I worked on were required to be accurate to 2 microns. Encoders were used only to verify proper functioning of the machine. Glass scales were used for position feedback.

Part of the tuning of these machine was a similar process. An accumulative error is easier to spot over repeated cycles.

[TTalma]

I think Macchips has the correct idea that tool offset may be causing your issue.

it's expected that the work coordinates, and the machine coordinates will be different. The only time I would expect them to be the same is when your work piece origin is at the machine origin point.

I notice you have a tool depth setter on your machine. I am not familiar with your controller, I use Mach 4, and have my depth setter connected to the probe input. When Mach 4 reads a probe hit, it records the value in the active work offset. If your controller works in a similar way, an easy test is to set your work offset to G54, record the current values in there, then run your tool depth setting routine and see if the Z value in G54 changed.

[robotek]

H01= Offset for T01 this is in the G43 Tool length Offset register, so whatever Tool Number you are using, it will have a G43 H04=T4 Offset Tool 4 or any number Tool you are using, does not need the zero T01=T1 same thing some controls may need it as T01

Thank you. I’m learning this G-code stuff and trying to make sense of it.

[robotek]

Ok, Somehow, the machine is running the code correctly. I did couple of things at the same time:
1.I edited tool paths in fusion 360. instead of bottom height being offset from model top in negative direction, I set it from model bottom with positive offset. Honestly, I’m not convinced this was the problem, anyway.
2. In the controller settings, I changed the general parameter 042 Enable Of G00 Inp Mode, OFF. Prior to all this endeavor, I set it to ON, it seemed to take care of steep decelerations. Put it back to default setting.