Carving going rogue on me

[Capt Bruce]

I created a Project file for a sign at FEMA and cut the first one successfully.

Went to carve the 2nd copy (the CW is all about repeatability) and ran into a problem 1 1/2 hours into the carve.

This is the intended carving region near the center left side as viewed. The letters are Centerline text. See first illustration.

http://i60.photobucket.com/albums/h32/ohneplo/R4SignPlan.jpg

When carving with Optimal quality selected the sign was 7/8 done and the 60 degree V Bit went down and carved a rogue line on the front of the capital R ruining the sign. Also the CL text on the arc of the DHS seal is misaligned. See next photo.

http://i60.photobucket.com/albums/h32/ohneplo/IMG_0763.jpg

I did not see the problem occur and thought that perhaps the sled had run into something. So I removed the card, went to my computer and checked the original file. Everything showed up as intended so I formatted the card and did the upload again. This time I set the file for BEST quality thinking this was how I ran the first sign and it did not have this problem.

Back to the CW, loaded the project, fresh board and ran it again. I say 7/8 ths of the way through because this time I stayed around the machine and checked it carefully. All seemed to be well until the majority of the sign's text was finished and it came back to carve the balance of the DHS Seal. It again misaligned the letters LAN in HOMELAND and then went right down and did the rogue carve to the left of the R again. I hit stop rather than waste any more time/wood but it's clearly repeating this unwanted mistake below.

http://i60.photobucket.com/albums/h32/ohneplo/IMG_0762.jpg

Does this suggest what the problem might be to anyone? Where is this rogue line coming from? Why not on the first sign if it's now showing up twice in a row? Maybe I should have bought the extra cost wood warranty as this could get expensive . . .

I've attached the MPC file to see if this helps anyone troubleshoot the problem. Thanks for your attention and hopefully advice toward a solution.

[rjustice]

Hi Capt Bruce,
It looks like it is a board tracking issue, like it slightly lost track of the "X" location. Are you using masking tape on the edge that rides on the brass roller?.. and is the board condition in good shape on the edge that rides on the roller?.... also have you checked head pressure yet? If you are carving in a cold environment and didnt get enough head pressure it could possibly slip as well...

As far as the expense of the wood... if you are having trouble, sometimes it is better to go to something cheap to test carve before putting the nice stuff in. If you have good dust collection, MDF is very reasonable for test carves...

Hope this helps,

Ron.

[bjbethke]

I created a Project file for a sign at FEMA and cut the first one successfully.

Went to carve the 2nd copy (the CW is all about repeatability) and ran into a problem 1 1/2 hours into the carve.

This is the intended carving region near the center left side as viewed. The letters are Centerline text. See first illustration.

http://i60.photobucket.com/albums/h32/ohneplo/R4SignPlan.jpg

When carving with Optimal quality selected the sign was 7/8 done and the 60 degree V Bit went down and carved a rogue line on the front of the capital R ruining the sign. Also the CL text on the arc of the DHS seal is misaligned. See next photo.

http://i60.photobucket.com/albums/h32/ohneplo/IMG_0763.jpg

I did not see the problem occur and thought that perhaps the sled had run into something. So I removed the card, went to my computer and checked the original file. Everything showed up as intended so I formatted the card and did the upload again. This time I set the file for BEST quality thinking this was how I ran the first sign and it did not have this problem.

Back to the CW, loaded the project, fresh board and ran it again. I say 7/8 ths of the way through because this time I stayed around the machine and checked it carefully. All seemed to be well until the majority of the sign's text was finished and it came back to carve the balance of the DHS Seal. It again misaligned the letters LAN in HOMELAND and then went right down and did the rogue carve to the left of the R again. I hit stop rather than waste any more time/wood but it's clearly repeating this unwanted mistake below.

http://i60.photobucket.com/albums/h32/ohneplo/IMG_0762.jpg

Does this suggest what the problem might be to anyone? Where is this rogue line coming from? Why not on the first sign if it's now showing up twice in a row? Maybe I should have bought the extra cost wood warranty as this could get expensive . . .

I've attached the MPC file to see if this helps anyone troubleshoot the problem. Thanks for your attention and hopefully advice toward a solution.
It does look like you are loosing board tracking, but some of that tracing looks like it is also in the "Y" movement. Is that the only place on the board that the carving is messing up? Since you are using the 60 degree bit for all of this carving it is carving in a vector movement. Centerline does jump all over the place on my machine so it is a little hard to tell if it is doing that on the whole board. I also noticed you have a stray group in your MPC. It looks like a useless function. Note some times computers do not do a good job erasing data, and it may have picked up some old data you wanted to erase. You might want to erase that group function in your MPC and reinstall the mpc on your memory card; it is a good idea to reformat the card.
Also when the Router head engages the “V” bit has lots of focuses to the Key Board site. Make sure your side plates are set to hold the board. And your head pressure is set right. The moveable side plate should have about 1/16 inch space between the plate and the full length of the board. Too loose or too tight is bad, too tight can take out your SANDPAPER gears

[Capt Bruce]

Ron and BJ,

Thanks for your rapid responses regarding the tracking error as probable cause. They teach you to always pay attention to the basics, or they'll get you or your men killed in combat. Your thoughts lead me to go down and check the cutting sled I've been using to save that seven inches for each piece.

Sure enough there were two worn or crushed spots on the edge contacting the brass roller. I did this 18 by 11.5 sign first a month or more ago and mostly smaller signs since then so the new wear spots on the bottom were not getting near the roller. Hit them this time and that's all she wrote.

I've cleaned out the unneeded group in the cutlist, made the top arc of letters one Centerline phrase, formatted the card and uploaded again. As I type the board is carving again on a new sled and I'll know if that was the gremlin in about an hour.

Thanks again for your helpful responses and hopefully this one is put to bed.

[rjustice]

I hope that this the fix!

Thanks for the feedback, and Happy Carving!

Ron

[Capt Bruce]

Happy to report the new sled with clean and straight bottom edge made the difference after those identical faults in the 2 carvings. Perfect copy of the sign this time with no rouge cut by the R and the centerline text in the seal was perfectly aligned even though carved up to 1 hour between letters all around the seal.

I've now learned that if I'm using a carving sled then checking that all important bottom edge is part of the pre-flight checklist every time.

Ron, I'm looking forward to the ROCK CHUCK and a bit quieter operation in my shop. Again, thanks for your help and the feedback note is entirely deserved. Back to making sawdust and signs. Happy carving Folks.

[Digitalwoodshop]

Good Job !!!!

AL

FCC(SW) Retired.

Masking Tape will help too.... The Rack and Pinion of the brass roller and sled..