strange thing happened

[stanv77]

Yesterday I was doing a 5 hour carve when a strange thing happened. The carve went prefectly but at the very end the traction belts started going back and forth and went into the project about two inches before I caught it and got it stopped. I hope this not the startof a problem with the machine. I have gone about a year with very little problems. I have changed the board sensor once and the traction belts to the heavy duty belts and broken bit a time or two but other than that nothing major. Has anyone have any idea what could have caused the problem?

[TerryT]

Sounds like the machine lost it's X position and was searching for the proper location. Check the usuall suspects, brass roller, O ring on the brass roller, X encoder. Al will have more complete list of possibilities. Hunting is the term we used to use to describe that kind of action from servos.

[Digitalwoodshop]

Five things will cause the board to rock back and forth....

1 is sawdust built up in front of the rollers causing it to stall and try to self correct.... Do you use any kind of dust suction?

2. The board edge on the bottom where the Brass Roller is missing some wood and the brass roller lost contact with the board.

3. The board came out from under the roller now only being held by one roller and raised and lost contact with the brass roller....

You are seeing the reason.... The Brass Roller is the feedback to the belts telling the computer that the board is in the correct position, when it looses contact it rocks back and fourth....

4. Board is tapered in Thickness or Width.... JAMMING..... OR touching the Right Side Guide... Board should never touch the right side guide...

5. The belt has rolled over at the brass keypad side, forward belt.... But in your case I don't know if a rubber belt can roll over...?

Reading the Tips and Tricks is your Homework... Lots of good info in there.... And if you use masking tape on the bottom of the board at the brass roller it will provide a soft place the the brass roller to make a rack and pinion with the board.

AL

Edit... Terry types faster....

[TerryT]

Al, I had forgotten about sawdust buildup on the rollers. A five hour carve is a good place to find this problem if you don't have good dust removal, especially if using a wide board.

Awe shucks Al, I was just standin' here when it came in.

[stanv77]

Thanks guys for the reponce. I have the rubber belts so I don't think they can roll over like the original ones did. I have got a dust collector running for the length of the carve so I don't think that is a problem either. But I will check to make sure there is no problems in these areas. I have another long carve comming up in a day or two. I will see if this problem shows up again. I am hoping that I can repair the hole rather than recarving .
Thanks again guys