Defect in job on rotary

[Robbo Sisson]

Hi all,
First post be nice! lol

I am pulling my hair out with this rotary device on my Chinese 50w co2 laser.
it looks like it is not turning every time it meant to i dont think its slipping as i can get the error in the same place every time

I have some photos to explain,
first error
http://i186.photobucket.com/albums/x31/Robbo2232/20151122_110313_zpswblyetvv.jpg (http://s186.photobucket.com/user/Robbo2232/media/20151122_110313_zpswblyetvv.jpg.html)

Second error mirror image just to see where the error hapens
http://i186.photobucket.com/albums/x31/Robbo2232/20151122_110320_zpsavqrxqr9.jpg (http://s186.photobucket.com/user/Robbo2232/media/20151122_110320_zpsavqrxqr9.jpg.html)


and on flat glass
http://i186.photobucket.com/albums/x31/Robbo2232/454a9dbc-cd3a-46a0-a0f3-02f4250c6016_zpsuw40z4n5.jpg (http://s186.photobucket.com/user/Robbo2232/media/454a9dbc-cd3a-46a0-a0f3-02f4250c6016_zpsuw40z4n5.jpg.html)

do i need to change setting in RDworks for rotary? it is the roller type not a chuck.
or a faulty rotary or user!

Thanks

[Rich Harman]

I would run it again and watch carefully to see if it is slipping. Glass against metal rollers does not have the best grip A wide rubber band around each end of the glass should help.

[Mike Schnorr]

Does your rotary have a hold-down inside the glass? (My Epilog has an adjustable spring-loaded rubber wheel that rides inside the glass to keep if from slipping...) I can take a picture if you want to see how it works!

[Kev Williams]

Hmm...

in each glass you have 2 distinct changes. The change in the reversed glass is about twice as far apart as the change in the forward glass...

What's puzzling me is that in the forward glass, the change runs right thru the "3", but the 3 appears unaffected. Yet everywhere else on both glasses there's a distinct bright line where, it appears to me anyway, the glass just sat there while the laser rastered back and forth a few times before the glass moved again. So why no such line thru the 3?

Regardless, it seems the glass didn't move for a period of time. I'm not sure how your rotary is driven, but I have to wonder if something in the works is causing the rotary to hang? Like some grit in a gear or something...?

>edit< -- I also just noticed the "B" in Birthday and "U" in Lauren is also unaffected? Why would the B and 3 and U engrave correctly while everything else in the X-path didn't? The B and U are above and below the main 'error', but the 3 is right smack in the middle! Maybe a data error...?

[Robbo Sisson]

I think there are a few layers I will check when I get home,
I have sprayed my rollers with a few coats of plasidip and they grip quite well.

[Rich Harman]

I think there are a few layers I will check when I get home,
I have sprayed my rollers with a few coats of plasidip and they grip quite well.

I would flatten into one layer, otherwise the rotary will have to move move back and forth - greatly increasing the chances for misalignment.

I like the rubber bands (or O rings) because it limits the contact points to just four. If your rollers are fully covered in Plastidip then the glass is making contact for the full length, any imperfection on the glass or the roller could cause a problem.

[Dan Hintz]

The bright line is where the laser is engraving more than once... either the item is slipping, the motor isn't moving, or the motor is putting the item back into the same spot (multiple layers and such).

[Greg Holt]

Look like the lettering and floral emblem are on two different layers. Flatten it on to one layer so it is done in one pass.

However that does not explain the skip or slip. Which is happening at approximately the same place.

And makes me wonder if there is something mechanical going on. Why should it slip in almost the same spot on the second pass?

[Ken Higginbotham]

I'm thinking you need a round jig to hold the glass...

[John Frazee]

I use a Chinese rotary attachment that has big black O-rings as the bands the glass rides on. Sometimes I wet mine to get a little more traction and almost always add weight inside the glass. I put a deepwell socket inside that turns along with the glass. You could probably also use a roll of quarters.