Pattern doesn't stay aligned

[doutt]

Hello,

I created the attached wheel pattern and the resulting project part is not correct. It seems that the cutting head "moves" to a new location each time it does a new process.

Any thoughts or suggestions?

The part was NOT under the rollers and I just replaced the belts. Measuring the board was OK. The process completed without a hitch just wasn't what I expected. I have the latest firmware.

Mark

[ChrisAlb]

Assuming the board was in the machine the way it is in the picture, it would seem the X axis slipped a little.

Could be too light a head pressure, brass roller slipped on the board, Board maybe warped or the sliding guide plate was too tight to it.

[Ike]

Mark, I selected to snap a line and your lines are slightly off at 1/2 inch grid. I am not sure if that is the problem? If it was me and this is me! I would use the snap grid and make one wheel and mirror it 4 ways. Then give it a test on a scrap piece of wook.

Ike

[doutt]

Ike,

Thanks for the information. I created the initial wheel by creating each part and having it centered X&Y. I assumed that this would make everything aligned to the center of the circle. I then grouped it, told each item not be be centered anymore (without moving it) and copied and pasted.

I can try the "snap to grid" and see if that helps.

Mark

[doutt]

Chris,

The head pressure measures around 80# if I remember correctly.
I assumed that measuring the board before cutting would tell me if there would be any slippage issues. Is that a bad assumption?

Mark

[Ike]

Mark, I did notice all your lines except one was 5.6" then one was 5.470" That was one wheel. I made a center wheel using your design and then four more to you measurements and mirror the 4. Check the left side X line it is the 5.470" line on the center wheel that is from your original design.

I think it might be the lay out, without using a grid you are eye balling it and I did mine with a grid and it may still need adjusting to the center.

Give it a look.

Ike

[w2csa]

Mark,
Any chance the red lock down lever was not locked?
This happened to me once and created a similar effect.
I am very newbe here... just a thought.

Chris

[ChrisAlb]

Chris,

The head pressure measures around 80# if I remember correctly.
I assumed that measuring the board before cutting would tell me if there would be any slippage issues. Is that a bad assumption?

Mark

Mark,

Not "necessarily" a bad assumption however there is more drag when cutting versus just measuring. But if that's your head pressure that should be fine.

Let me check your file......BRB.....

[Amonaug]

You said it wasn't under the rollers and it looks like you don't have the exttra 7 inches to stay under the rollers. This can cause problems and probably is what caused the slip as it was only under 1 roller.

[ChrisAlb]

Mark,

Ike was right about 1 line (the first) in each group being shorter than all the 5.6 ones.

I deleted 3 of the groups, re-centered the one, made that line 5.6 and then copied the 3 back.

However, that one line doesn't explain the cut results in your picture. If you notice, you'll see that more than one line was cut off center and the two wheels on the right are further off than the two on the left. It's hard to tell from the picture but it looks like the drill holes are in the intersections of the lines and the circles are cut off center.

This still tells me that some sort of X slippage happened. Be sure the board is parallel and the guide plate not too tight. If it's a really smooth (slippery) board, run a piece of masking tape on the bottom for the brass wheel to get better traction. Although I've done many carves not under rollers, it's a good idea to have the extra 7" to stay under rollers when doing cut outs.

[Digitalwoodshop]

The board lost contact with the brass roller....

1. Head Pressure like is posted above.

2. Not Under the rollers, if the board is TOO short it can TIP UP loosing contact with the BRASS ROLLER and making errors in the X Axis.

3. Masking Tape is your FRIEND.

AL