[bald9eagle]

I am trying to cut turkey pot calls on my machine. I just have got the machine going so I am still tackling the learning curve.

Cutting the calls is pretty simple stuff. Drill a few holes, cut a few pockets, profile the outside of the call. I started the program by drilling the holes. I then pocket cut the center 1" hole out. Everything is fine so far.

What happens next is where I am having issues. The next line of code is for the pedestal. This is a .200 deep pocket on a .750 thick piece of material. The zero on the Z axis will flip as if it is trying to zero on the bottom of the material. When I drew it out on Cut2D I drew everything at once so it's not like two separate drawings combined or anything. The g-code says that the Z is -.125 for the first cut but it has re-zeroed and drops down close to .500 deep.

Any guesses to why the Z re-zeros itself when going to the next line of code?

[bald9eagle]

I might add that in Cut2D that the preview showed everything to cut as it should.

[ger21]

Does the Mach3 DRO display the actual tool position?

Are you changing tools?

I don't quite understand what you mean by re-zero? The g-code doesn't re-zero anything.

Can you post the g-code?

[bald9eagle]

I won't be able to post the g-code til later. What it does is finish cutting the center hole (.755 deep pocket on .750 material). It then goes to the Z safe of +.200. When it goes to the next step of code which calls for a .205 deep pocket it goes straight past the zero I set on top of the material and resets the zero about a half inch deep into the material. I looked the code over and to my inexperienced eyes the first Z move I see is -0.125. Problem is that when it goes to the safe move of .200 it believes that it is now at .700 (+/-). I haven't been watching the DRO to see when exactly it loses it's mind.

Summary....Zeroing the tool on top of the material. First two pieces of code run fine. Drills eight 1/4" holes .755 deep. Moves to +.200. Raster cut for center 1" hole to .755. Z moves to +.200 and then plunges about .700 deep. When I stop the program and jog the Z to the top of the material I am around .500 +/-.

I wasn't intending to say that the G-code re-zeroing. I think it is something I am missing that is pretty simple but I'm not sure what it is I am missing. I think the code is good. Like I said on Cut2D the preview looks exactly like it should. I think it is something on the machine setup or a setting in Mach3 that I have messed up. One issue may be with configuration of Mach3. I used the XML file from cncrouter parts and it runs things fine but I did get an alarm saying that the Z axis tuning and kernel speed wouldn't work together, or something like that.

One thing I did do was disable the dir low active (atleast I think that was the one) to reverse the Z+ and Z- on the DRO so that it was running correctly with Cut2D. I don't believe that is the issue though. I just don't know what would make the Z think that it was at +.500 right after running correctly on the previous tool path.

[bald9eagle]

Oh and I am using a single tool. No tool changes.

[bald9eagle]

One thing I will try is calibrating the Z encoder again.

[ger21]

One thing I will try is calibrating the Z encoder again.

What do you mean by this?? Is this a stepper machine? You shouldn't have an encoder, and I've never heard of calibrating an encoder.

It's sounds to me like your machine is stalling and losing steps on the Z axis.

When it's finished, use the MDI to go to Z=0, and if the bit is not in the correct place, then your machine is probably losing position.

[bald9eagle]

I'm using the wrong jargon. I couldn't think of what I was wanting to say. What I meant was reset my steps per unit. Calibrating the Z Axis steps per inch. I had just got through watching a video on youtube where a guy was explaining encoders and I couldn't get that out of my head.

So is that what I need to look for when we talk about losing steps? What usually causes a machine to lose steps?