Tried to cut my first part today (another first since recent issues were solved). Zeroed the machine and started cycle.
At first it looked like the part was coming off center but it was too late so I waited for the full cycle. The result was nothing like expected.

Its a pretty easy task. just a flat fixture with the shape of a guitar fretboard. It will be used to hold a fretboard blank to mill.... (eventually!)

Would someone take a look at this G-code and tell me if they see anything wrong? I attached a screenshot from Mastercam so you can see the drawn part.

G-code

I did not see any thing wrong with the code. If your using stepping motors can they support an F50 feed rate? The codes cutting arcs with F50 and G1 with F10, looks a little odd. Try F5 for the F10 & F50 and see if it works better.

Hi,
as Atlas says maybe the load is to high and you lost steps or your part moved.
At the end of your code you should change the G90Z0 to G90Z2.
It looks like your Y axis is running in mirror image,  Y+ and Y- are  reversed ?

just a thought

Alex

Alex and Atlas,
Thanks for your input. I did change the last part of the code as recommended.

Made sure the computer was restarted, no other programs running and the blank secured with 6 screws.

Loaded the code and started the cycle. Everything went super smooth. I kept my eye on it the whole time, at one point towards the end of the code something strange happened,
the tool moved over to the Y- for no reason and kept cutting like the Y zero had changed. At this point it was too late as that part was ruined. So I waited for the cycle to end and here's what I saw:
The Y axis moved over about .300"
As you can see in this picture the tool is way off center. I don't know why!!!
Starboard is pretty expensive that I know....

You may want to use a piece of scrap to gain some experience on using your machine making note of what it can and cannot do when machining different materials. If an axis skips you will loose position, it can be minor or major as to the degree of position loss.

RICH

Your Code seems to be OK.
It looks like it has something to do with your setup and you are loosing steps.
Like Rich said take a piece of scrap for testing. You may try to run the code with low feedrate and only do a slight cut ( only scratch the material )
and look if it come out correct. If so then try to reduce the vel. and accel. in motor tuning. then try again with a normal cut. ( in a piece of scrap )
If the slight cut is coming out wrong then your setup is not correct or you may have loose cable or similar things.
BTW. It's still looking to me as your Y axis direction is reversed.When you are in front of your machine ( X movement to left and right)
when you then jog to Y+ Direction the tool should go away from you.

Alex

Thanks for the help and tips guys. I'll take all your input into consideration.

The thing that's boggling me is how the axis loses its place. If it was losing steps would it do it gradually or one big move in one shot?

My Y moved over a whole -.300" in one shot. Everything was running fine and then the cutter just moved over and went on like normal.

Could it be the computer? I am running in an old IBM notebook using smoothstepper.

Is that " shot " always at the same place or random ?
Is the position in the DRO the same wrong position or is the DRO Position still correct?
If the DRO position is correct and the tool is way off then I think it may be a mechanical problem.

Alex
 

The DRO is correct.
I ran the program one more time today. Kept a real close look on it, somewhere between lines 170 and 175 the tool "stuttered" a bit and lost track of Y again.
I stopped the machine and sure enough, Y was of by about -.300" So I zeroed the machine again and ran the program. This time it ran all the way without any mistakes.... There's a little nick where the machine lost position from the previous run but this time went fine. I am really lost now. I'm thinking that and one part of the cutting the machine has a hard time and may loose position as it fights the feed rate?