Edges being cut but nothing else

[Dingus McGee]

My situation is this: After spending some time making sure the image is coming out on PVC like I want it, I load it into the machine and let the hamsters run.
The head moves up a bit farther than I told it to (Yes, checked calibration of steppers and they all move the distances the program tell it to) and then drops down and tries to cut into the material as the bit is moving to the start point.
The bit dips into the material at where the edge is supposed to be and then lifts up about 1/4-1/2" jiggles a bit like it is carving something and then moves back down and over to the new spot on the edge and cuts a bit into the material, rinse/repeat. tried adjusting the dro, the zero, adjusting max depth, pass depth, sacrificed a chicken I even pee'd on a spark plug.
Same result or slight changes but only the edges are getting any tool bit love.
I am running on a Mach3 supported machine.
The controller are new, the steppers are new. Everything is lubed up, cleaned up and get a petting every time I walk by it. I even whisper sweet nothings in it's ear from time to time.
Everything dances like a ballerina when I am tasking it to cut pockets or shapes on aluminum and other wood or plastic bits but when tasked to play with PVC they seem to not like each other and it is almost too painful to watch.
I mean... It's almost Christmas and not a tree to be seen with all the awesomeness I am trying to hang on it with PVC ornaments!
SOO!!!
Any one else have this issue or am I so totally screwed up or just screed? I can post a video of it's antics tomorrow if ya'll want to see what it is doing. I would grab the pop corn and a cozy for the feet because it is spell binding inaction.

[antennasDIY]

It sounds like an inches vs metric thing. Mine did that when I messed around with it and it would jiggle a bit and then go back to home. It was only moving in mm's and not inches on the co-ordinate system. So instead of moving to the spot at 3 inches it only moved 3mm.
Maybe that's it I don't know, but thought I'd offer.

[Hermie]

Check to make sure you used the right post processor

[martin54]

If the machine is working fine normally & the preview in PVC looks good then it may well be a post processor error.
What do you use for toolpath generation when pocketing or profile cutting? You don't say if you use other vectric software for this or something else.
Can't think of anything else it could be, if you were losing steps or backlash because of the amount of z axis movement then I would expect it to cut chunks out all over not retract as it is doing.

[Dingus McGee]

Ok, new to the whole name of things stuff. Post processor?
I use Mach3
I make the file through PVC, load it onto a thumb drive and stick in the PC running my mill that is running Mach3 and hit the go button.
If there is a post processor I need to know about then I should be schooled about it.
I use cut2d for making other things and they turn out good unless I goober something up which has happened before.

So.
.
.
.
.
Whats a post processor?

[martin54]

The post processor is what converts your file to something your machine software can understand, in your case Mach3, once you have created the file you select the post processor before saving the file. In your case you would select one of the mach3 post processors, which one depends on how the machine is set up, either imperial or metric. There are inch & mm options along with one for auto tool change (atc) but you would need to set mach3 up to be able to use that one.

[Dingus McGee]

Ok I got it, cool. I am and always have been set to inches. I went in again and checked to see if it was still saving to inches.
Here is what it is doing


I have ran several other attempts and the same thing happens unless I drop the 0 to really low and then it just augers in and tries to cut out the core of the earth.

[Adrian]

Do you have the Z Zero on Stage 2 set to the same as you're using in Mach3? Material thickness on same page correct?

Could you attach the actual PVC file and the Mach3 toolpath file?

[Dingus McGee]

It wont post because the file is just a bit too big and paste says I have too many characters.

[Dingus McGee]

I zipped it. This is the file I want to cut. I have about 5 total and they all do the same thing.

[Dingus McGee]

lol Guess I have every one stumped?

[HerbE]

Dingus....can you post the .pvc file instead of the toolpath file. Would be helpful to see how you set it all up.

Thanks....Herb

[Dingus McGee]

I deleted all of them except this one. This I just made today to try some different things. It doesn't work either.
I made some changes to the .txt files and have done some tweaking and can get a little bit to work but it requires me to edit every Z path line and there is no way I am going to do that.
Let me know what you think.

[HerbE]

Dingus,
Went up to my shop, booted everything up, loaded the toolpath file you posted and it runs like a champ. No problems. I did notice that your safe z is set at 0.25", taking up almost 1/3 of your run time. Personally, I would make it no more than 1/16 inch. If you have a 1/16 or 1/32 inch bit, using one of them would give much more clarity on such a small carving.

Hope you get it figured out. The toolpath is good, which indicates to me your machine has a little gremlin in it somewhere.

Sorry I couldn't be any more help.

Herb

[Dingus McGee]

I have changed the up time to .05 and it speeds things up a lot so thanks for "fact checking" me.
I am going to hound mach3 forums to see if I can get some justice here. I have so many projects on hold because of this. They were part of a production package I was going to throw all in after the first of the year and now I am running in neutral on the other stuff I do until then.
Good thing I have my leather stuff to pay the bills!
Thanks for the help that you could give.