I am starting to see some weird Y axis issues.

I have added a slot feature into the fuselage of my Cessna 185. Nothing complicated, just a single 1/8 x 1/4" deep slot. Everything else on the fuselage is the same as what I have been making, other than that feature. I reloaded the .DXF file into the CNC software. It shows the slot in the correct place but when it cuts the slot, its locates it 1/2" off on the Y axis from where it is suppose to be located. I thought it was a glitch so I recut the fuselage and the software put the slot in the exact same place. Also, now the some of a pocketed area features are off. I checked my machine calliberation and it was dead on. I am pretty confident its a software issue as the rest of the fuselage cuts out fine. It seems as though features that are cut in a "chain" (like the fuselage outline) come out fine. Where the issue seems to come up is when the software jumps between features. For example make a slot on one half of the fuselage then jump over to the other half of the fuselage to make the same slot, the second slot would be off. You can leave the parts in the machine and rerun the program and it will put all the features in the exact same spot. So I don't think the machine is the issue, rather the software.

I also eliminated the possibility of it being the latest firmware as I tried running it on the old version and it did the same thing.

 

I don't believe I have any backlash. The only thing I did notice that seemed off was when the machine was milling out a pocket. What was happening was about every inch of travel on the x axis, I kept hearing what sounded like a bumping noise. After this happened I re-ran the same program and the noise was gone. I am not sure if it was the machine of the software.
My machine seems to be running pretty accurate. I can run a part, leave it in the machine, re-run the program and it will re-follow the original cut path within probably .005-.010.
I am pretty convinced that the CNC software has some issue. Something is going wrong during the .DXF file to G-code conversion or the information being sent to the machine is not correct.

I am going to try a copy of Master Cam and see if the problems go away.

 

A coworker who has a CNC router said he had the same problem I am having when he used sketch-up to gen the code. Apparently the accuracy was a problem, especially circles and splines.It had no problems with simple stuff. I don't know anything about sketch-up so I couldn't say for sure.
You may try getting a free copy of draftsight or AutoCAD and try them out to see if your problem goes away. Then again, you may end up with the problem I am having.

Maybe I can shoot you a copy of the code and see how it runs on your machine?

 

PlanetCNC controller should cut exactly like it is drawn on display. If it is displayed correctly then it should be cut correctly.
Is error always at same position? Please send me file that is cousing problems and your .settins file. And screenshot with mark where error is.

 

Yep the error is always in the same position. It I will work on getting you the files tonite. I decide to check the machine axis drives and guide rollers. The machine was starting to get a little sloppy on Y axis stepper belt tension and the Z axis guide rollers needed a readjusting. But, the adjustments needing to be made were small and I don't think it is the cause of the problem. I am going to try running it again this weekend. I am hoping the adjustments made were what is causing the problem. Its hard to imagine the software is having an issue.

 

I think I got it sorted out. I did a redraw of the DXF file,, caliberated the machine (although it required no changes), installed an aluminum "x' axis belt drive roller, tightened up all the axis guide rollers and reset the belt tensions. The problem seems to be gone. Don't know which thing solved the problem but I guess what counts it that its solved.

 

Thanks Mark! I actually have a banner finished. I figured I would send it too you when I am ready getting the kits finished. Going to an airfoil wing, converting my files to mastercam and also learning mastercam at the same time. Oh yea and web design Its been a 105° outside is all slowing the process down. I have to go out at 7:00pm to do all my flight testing. I haven't had any software hickups, The wing core templates that I cut in lite ply came out perfect. I matched them up to the printed templates from Profili and they were identical.
At 12:30am this morning I was in the shop running the core templates on the PP. I'm not a big guy and I was melting and miserable in the heat. South Texas summers can be brutal.