"Jitter" on Curves

[David Rust]

Hi All,

I have been experiencing a new problem with my machine. While vector cutting curves the cuts are not smooth, they appear to have a "jitter" or "ripple". I called Epilog and they have been great as always, they identified some exrtra slop in my x-axis linear guide and sent me a replacement. After installation the problem is still there. Epilog is still looking at the problem.

Has anyone experienced this problem and if so what was the solution?
Jitter1.bmp


Thanks,
Dave Rust

[Joe Pelonio]

Has the X rail been cleaned and greased well?

[David Rust]

Hi Joe,

I replaced the whole x-axis rail and carriage with new bearings with a new unit supplied by Epilog. Here is another pic...
Jitter1.jpg

Edit: The words were laser cut left to right along the x-axis of the laser (90deg to the shown picture)...

[Mike Lysov]

Do Epilog lasers have something called vector quality in their control panels? It may happen that these settings have been changed somehow and it can cause this jitter problem. I had exactly the same problem with my GCC LaserPro and it was caused by wrong setting in Vector Quality. All straight lines were cut smooth but anything curved had this jitter problem.

[Scott Shepherd]

Can you post your speeds, please. That might help in diagnosing.

[David Rust]

Hi Scott,

My settings are 100/18/750 (s/p/freq). I am cutting paper.
This is a new problem, I have cut many designs out of paper with these settings and have not had the degradation in quality that I now experience.
I will try reducing power and do a comparison for troubleshooting.

[Michael Hunter]

The only time I had anything like as bad as that on my machine, I found that the mirror/lens assembly was slightly loose on the carriage.

Other things to check -
If you took the belt off when you changed the rail and bearings, did you get the ends exactly straight when you put it back on?
Did you work as much grease as possible into the new carriage bearing? (AFAIK they are oiled but NOT greased when new).
Belt tension.
Turning mirror at the end of the beam.

Otherwise, is anything vibrating the laser or the floor it is standing on (compressor, exhaust fan etc.)?

[Glen Monaghan]

Be sure to clean the encoder strip and blow any dust out of the sensor on the gantry, if you haven't done that recently...

[David Rust]

Hi Mike,
I had the problem, then changed the rail and bearings with new, now the problem still exists.
I did not pack the new bearings with grease, thanks for the heads up, I will pack them. Right now they are very well oiled and they run very smoothly (because they are new), my next task will be to pack them with grease.
Belt tension appears to be good, I am letting the spring loaded tensioner do its job before tightening the screws, a finger push against the belt verifies the tension feels about right.
I have not checked the optics... I'll look at the mirrors and lens next.

Thanks!

[Scott Shepherd]

You might try reloading the driver as well. Sometimes that resolves those types of issues.

[Kim Vellore]

When I had this issue Epilog told me not to exceed 25% speed on vector cuts. I think this is a design issue I thought it was only with older machines, you just cant go higher speeds on vector cuts without this vibration. I see it more prominently when I vector cut diagonals, Two of my friends also on this forum have the same problem their only option was lower speeds.

Kim
Epilog 24TT

[George Brown]

I have the same problem on my ULS if I vector cut at too high a speed. Poorly written software/hardware design, but nothing I can do about that.

[David Fairfield]

Kim, that is not the normal sort of jitter I get vectoring curves and diagnoals at any speed on my Epilog. Even at 100 percent speed the jitters are just little tremors, acceptable for most crafts products, but not the sort of fine miniature work you and I do. The only time I experienced a prounounced jitter similar to David Rust's was when my belt needed re-tensioning. Followed the instructions the tech dept sent to me and the problem was solved. I wish Epilog would put all that good troubleshooting info into the manual inthe first place! My guess is something is loose somewhere.

Dave

[Greg Bednar]

David, can you post the .CDR file so I/we can take a look at it?

Hi All, I have been experiencing a new problem with my machine. While vector cutting curves the cuts are not smooth, they appear to have a "jitter" or "ripple". I called Epilog and they have been great as always, they identified some exrtra slop in my x-axis linear guide and sent me a replacement. After installation the problem is still there. Epilog is still looking at the problem. Has anyone experienced this problem and if so what was the solution? Jitter1.bmp Thanks, Dave Rust

[David Rust]

Hi All,

Here is the .cdr file. It's pretty simple, all hairline curves.

Drust_Jitter.cdr

Dave