laser shifts during engraving

[Craig Hogarth]

This is the second time in 2 weeks that I've had my engraving shift in the middle of a job. Last week is was on a rush job on something that I only had one in inventory and this time, it's a good sized production run with just enough material to complete the job.

This is an orca ornament. as you can see in the oval, the image has shifted. While it only looks like it happened in one spot, it actually happened the entire line. It just happens to line up with another engraving. You can see on the tail how far it was offset.

btw, the orca was rotated 90 degrees when I engraved it.

I threw away the other piece that was destroyed, but as I recall, the mess up happened about 2 inches from the previous mess up. It only does the one shift and other than that, the top and bottom of the engraving is perfect.

Any ideas?


http://img237.imageshack.us/img237/3591/messeduporcant2.png

[Joe Pelonio]

I'm not familiar with the ULS but on the Epilog that can be a symptom of a dirty encoder strip but I have also seen a file mess up when going over. Try shutting the laser down, then resend and try again, maybe use scrap to avoid wasted material.

[Craig Hogarth]

yeah, i did shut down and started over and it worked fine the second time on both occasions. I've seen all you epilog guys talk about that decoder strip, not sure if i have one either. I'm sure another ULS owner might know though. :o

[Stephen Beckham]

Craig,

Epilog owner here - but I've had similar issue once or twice when I rotated a .BMP file that I import into Corel. You say the target was rotated 90 degrees when etched... Did you rotate the image in X3 by clicking then dragging to the point you want it or did you use a ROTATE command?

When I need to rotate now - I will edit the image in Corel Paint, use a rotate command - then save it back to the X3 file. Not sure if this applies - but figured I'd offer it up for a possibility...

Good Luck

[Craig Hogarth]

I used the rotate command on this one. I always use it when it's 90% turns.

This is a vector drawing, not a bmp. The one I ruined last week was done with both text and vector.

[Frank Corker]

Normally looking at that I would agree with Joe - dirty encoder strip. I too have seen the EPS and ai files alter in Corel, especially when it comes to resizing them.

There is obviously a way of checking which it is. Run it again with the whale further to the right and if the step moves it has to be encoder. If it doesn't it has to be your graphic.

If it is the graphic which is correct on your screen but not when you print select it, then choose 'bitmaps' and 'convert to bitmaps_' - then just do another trace. The problem should disappear.

[Craig Hogarth]

Frank, sorry, I didn't mention it earlier, but it was a whole slew of ornaments. I was doing them on 4.5x24 inch laser thins and the "line" went across all the ornaments. I'm sure it wasn't the graphic.

[Frank Corker]

Craig it must be the encoder strip then, it's the only thing I've seen that could do that, I've only had it once but when I checked along the strip I found a tiny piece of something on mine and when it was removed the problem was gone.

[Mike Null]

I would suspect a communication problem between pc and laser. Check your cables and connections. If you have a spare cable change it.

I don't know about this one but it won't hurt--be sure your laser is your default printer.

I had similar problems with my ULS several years ago and it was a cable issue.

[Rob Bosworth]

Craig, I think you are seeing the same thing others experience with their ULS systems. It is not an encoder strip fault, because ULS systems use open loop steppers rather than the close looped servos used on Epilogs.

How old is your machine? When was the last time you replaced the X axis belt, bearings, idler on your system? If recently, did you clean the cogs off on the drive gear?

My guess is your X axis gets "lost" or slips and then just engraves it wherever it is. I could be wrong, but I see more slips with belts and bearings than I do with bad firmware or X axis motors.

[Sandra Force]

I don't run that kind of laser but, I would think that with it being only once in a while I would look at the x-axis. Clean it completely and check it for the carriage being a tiny bit loose. Had that problem on both Epilog and Kern and the fix was the same for both. Tighten up the carriage screws on the x-axis and clean the tracks and belts if any. What it looks like is a micro amount of sticking on the return run is holding the carriage up and making it look like a jump.

[Mike Mackenzie]

Craig,

First off there is no Encoder strip, How old is the system? When did you last change the Idler, Belt, Bearings? It has something to do with one of these or the printer cable.

Because this is the easiest thing to do I would change out the cable first and make sure it is not a communication problem.

Next thing try and move the image to a different spot on the engraving table. If you are engraving it at 0,0 try to move it over to 0,12. This will tell us if there is a flat spot within the X axis belt.

Clean the bottom of the rail real well get a q-tip and really get in there and clean it.

Inspect the drive gear that is on the X axis motor and clean it if you notice anything.

If that all does not correct the problem then I would replace the idler pulley and bearings, do one at a time to see if one corrects the problem. I would start with the idler. If you have a bearing supply house around you take the Idler off and you can pop out the top and bottom bearings and see if they can match them. Other wise the Idlers are only $25.00.

Keep me posted.

[Craig Hogarth]

thanks Mike. My sales rep is going to be in my area next Friday and will stop by to look at it. He agrees with you, but he also said it could be my air assist hose as well knocking it out of place.

About 3 months ago, my exhaust fan crapped out in the middle of a large job. Since I was working on a timeline, I continued working on a large order of red rowmark. I can still see the residue on the hose.

I really need some training on doing a thorough cleaning and he's going to help me with that along with replacing my bushings.

[Mike Mackenzie]

Craig,

That is the best option If you need any help just let me know.