Machine Calibration

[SpiffyDog]

I created a sign that is 10" x 23", with a 90 degree V edge route set to .375" deep. After each pass, the bit would go a little deeper, as expected. However, the measurement of the board on each pass was off by about 3/16" on the length. It's as if the whole board would shift 3/16ths after each pass. I also keep the machine vacuumed during machining to keep the debris from causing any interference. The pictures are of the edges at each end. Any ideas before making the call to CW support?

[DocWheeler]

Spiffy,
It sure seems like the machine is losing track of where it is, how long is the board you are carving? Is it "rocking" a little as it travels from one X extreme to the other? Or, is there a Cup in the board that would allow it to "skim" the sensor?

What part of the State of Ohio are you?

Ken

[SpiffyDog]

Ken,

The actual board is 31" x 11 1/2". The design board is 24" x 11 1/2". The sign outline is 10" x 23". The board is poplar which was planed prior to machining. Also, the extension panels are level with the drive belts. As I was observing this, I thought I would attempt to "manually adjust" while it was on the last two passes by applying a bit of pressure (pushing) in the direction of offest. This did not affect the cut path whatsoever.

I'm located in Circleville, which is about 20 minutes due south of Columbus on SR 23.

Keith

[DocWheeler]

Keith,
While eating a bite of lunch, I realized that my first thoughts were off-base since it does the same thing on both ends. My next thought was that it was thinking that it had a "different" angled bit than it actually had, but since the corner in the Y direction starts off right - that can't be the problem.
The only thing that now makes sense to me is that the X position sensor got progressively looser as the carving progressed. But that increase each time would have been 3/8" which would be way too much for what I was thinking.
But, somehow the board is moving in the X direction without sensing it. Since the error seems so uniform, it must be something mechanical rather than random "skipping". My... I got to rambling.
Be sure to post the cause and solution when you get it figured out.
Seems you are the closest to me of anyone I've found so far.

Ken

[SpiffyDog]

Ken,

That is a great assessment. This is quite frustrating as I had planned on spending my weekend filling a few orders on home signs and now that plan's shot. I had to change plans and get out and mow the lawn, which is good therapy, since it takes me about 4 or more hours to do. After thinking about it a bit (cooling off period), I'm now off to take a peek at the machine. Not sure what to look for but I'm going to peek anyway.

I looked on the map to see where Waynesville was. I was close to your area many times as my daughter attended Miami U and the drive over took us close.

Keith

[DocWheeler]

Keith,
If the raster carving still works OK you could still do the signs, just cut them out with another tool.
Also, I PM'ed you.
Hope you can get this resolved.

Ken

[John]

On the beta machines there is a little brass roller between the feed trays on the control side of the machine. It is the board sensor (I think) and keeps track of where the board is. It needs firm contact all along the edge of the board to give consistent results. If the bottom edge of the board has any defects, ie. knot hole, etc. the readings will be off. On the beta machines the spring wasn't strong enough to get proper pressure against the board and a small piece of rubber tubing was used as a "shock absorber" to increase the pressure. I had similar problems you are describing when I replaced my feed trays and didn't put the little piece of rubber hose back in place. It was laying on the workbench when I got everything back together, but I hadn't a clue where it came from.

Hope this helps a little as I am sure there are probably a number of other things that could be causing your problems.

[SpiffyDog]

I had similar problems you are describing when I replaced my feed trays and didn't put the little piece of rubber hose back in place. It was laying on the workbench when I got everything back together, but I hadn't a clue where it came from.

Hope this helps a little as I am sure there are probably a number of other things that could be causing your problems.

John,

What rubber hose are you specifically talking about on the feed trays? I've had to replace the belts twice but do not remember seeing anything like that. But that doesn't mean that I somehow lost them.

I did examine the brass roller and it does have the rubber ring as mentioned. It appears to be OK as it's does not seem loose. I also took a board 47 inches in length and had the machine measure it several times, each time positioning the board in a different location. The measurement was always within .01. However, this is not really a good test since the board is not moving back and forth. I'm sure that the machine finds the end, sets the X position and then finds the other end and calculates the distance.

Keith

[Kenm810]

Keith,

I seem to recall a few posts referring to the step action a little similar to your problem. I'm not sure if this will help. but it sounds close. Search for Jon Jantz's post 1-02-07 "cut path problem"

[SpiffyDog]

Keith,

I seem to recall a few posts referring to the step action a little similar to your problem. I'm not sure if this will help. but it sounds close. Search for Jon Jantz's post 1-02-07 "cut path problem"

Ken,

Thanks. After reading that post, I'm a bit intrigued about the board roller sensor. Although the piece of wood I was working with had enough material to stay under the rollers, the piece was long enough that it could possibly affect the roller pressure. I did find that one of the fold out trays came out of adjustment and was a 1/16" lower than the board. I'm not sure if that is enough to cause this problem but I'm going to re-adjust and try again using a test piece.

A project for tomorrow...I'll keep everyone posted on the results.

Keith