Issue with machine skipping across project

[JDPratt]

Any guess what is causing this? not just htis project but all projects carved on this machine are doing this. Skipping some lines, carving some lines deeper, etc. (project carved on Optimal).

[lynnfrwd]

Sand paper belts? CarveTight or QC? Sharp or dull bit? Are those lines running in the x-direction?

[fwharris]

Dirty Y/Z truck bearings, dirty encoder disc in the Z motor to name a couple.

[JDPratt]

Sorry, I should have put in more clarification. Version "C" machine with rubber belts, Carvetight, new 1/16" bit.

[ktjwilliams]

One of my machines did that ,,, My issue was a bearing ..

[FWMiller]

Had this happen just a couple weeks back. Then I ran a few other projects without major issues. But periodically I had z depths that were off. Turned out to be a bad FFC cable with an intermittent open. The cable finally gave out last week and after replacing the z motor assembly first, finally found out it was the cable.

[lynnfrwd]

When it does it on other projects, is it the same pattern of lines?

Is this along the length (x-axis) or width (y-axis)? I can't see the whole board.

[Digitalwoodshop]

Your picture is labeled Carvewright Issue... My first though was operator error, sorry.... Need to ask.... Was the board not supported by both rollers letting it rock and roll around being held by one roller?..

IS the big line 3.5 inches from each end in X? Letting the board LIFT off the table into the bit making the lines.

Need to know a little more about the board setup in the machine during carving. Did you have additional wood to support keeping the wood under both rollers.

No hard feelings but sometimes it is just how the project is setup.... the closer you look at the picture you see the first line what looks like 3.5 inches down from the top then the last line 3.5 inches above the bottom then a bunch of LOOSE BOARD in between....

SO if that is NOT the issue.. then you have a loose Y Roller Bearing letting the head ROCK changing the depth...

AL

[JDPratt]

On other projects it is not the exact same pattern of lines but the lines have the same effect on the overall carving. The lines are going across the width of the board. There is plenty of room between the end of the board and the carving. The board for this carving is actually 12" longer than the project board so the 3.5" room should not apply here.

No offense taken Al. I understand that sometime the simplest problems result from the simplest of dumb mistakes. I will check the Y roller bearings.


Update: The Y roller bearings seem to be fine and have no play in them.

[DianMayfield]

I have a spare cable, I will have to put it in and see if it clears up the last bit of my issue, Thanks!