Problems with Epilog 24EX not printing in correct location ~ HELP!

[Edward Ike Brown]

Hello there - I'm having some problems with my Epilog 24EX. I'm confident on working on each of our CO2 lasers but this has dumbfounded me.

Recently we have had the X-Axis motor go bad, so it was replaced (movement was very rough compromising quality) and the bearing/bearing guide was eliminated as a problem. Now she is nice and smooth, aside from this problem. I understand after such a replacement the home will not be the same, that's fine and right now I'm compensating for the margin error but something has come up.

Scenario - I send a file to the printer, live or manually executed, it will print correctly (the first time), if I need to repeat the job, simply by executing the exact same file via dashboard on the printer it prints a little to the right, or left. Same file, didn't adjust the focal point, just a simple repeat. Its even happened when sending a file while the printer is online (live print), it just doesn't print in the same place or correct place twice, and now even the initial print. When rebooted (the printer) it finds its home and prints correctly, same if I turn the machine off and then back on.

I did have a couple of the X head flex cables (signal to the decoder on the head), I've just replaced the older one we had on it. I know these will go "bad" after some use so I keep some on hand, Epilog has also stated to flip said cable before replacing the entire band, long story short, it has a new one. I was prompt to replace it since the problem above only seems to affect the horizontal tracking of the head, vertically it is fine.

SO, if anyone has a idea or tip that could help that would be greatly appreciated! I've gotten many useful answers before here (forgot my old name and password, hence this single post) and I thought I'd post my problem and see if anyone might have a clue, or at least a starting point - Many Thanks in Advance!!!

If it helps here's some background to further understand my system -

Epilog Legend 24EX
Networked via LAN/hub/multiple PCs
All print jobs are executed from CS5
Both optic strips have been religiously cleaned properly with mineral water/detergent soap
All ball and roller bearings "appear" to be in good condition ( no unusual noises/manual movement )
Firmware is up to date
All lenses are clean and print quality is great
Auto focus and air assist have been disabled
Laser is aligned across the table as of the 1st of this year
Exhaust system is running fine with adequate air flow

My next guess would be the horizontal (X axis) decoder/optic reader - the Y axis decoder was cleaned properly when I replaced the motor I mention above since I had it off the armature.

Again thank you in advance for any opinions/tips/help! :) and have a safe Easter!

[Joe Pelonio]

I think I'd still start with getting the x belt positioned and tensioned properly. If too loose it could jump a few teeth at speed.

[Martin Boekers]

Hmmmm a few things to try.

Take the reader off and clean it. I use lens tissue and lens cleaner. Then blow it out with compressed air
I've had a hair stuck in there before and it would move a bit so I had positioning issues.

There is an "x" calibration in the (I believe) maintenance menu. CAUTION contact Epilog first on this.
I was miss told about the process from someone there and it blew a mother board, Epilog DID take
responsibilty and shipped a new board at no cost.

How old is the encoder strip? Maybe past it's time.

Have you tried positioning the piece at the opposite side of the table and see if you get similar results?
that may narrow it to a bad section on the encoder strip.

And as Joe said, make sure of tension on the belt.

[andrew zen]

I rebuilt a 24ex. If the belt is loose, things can be off, but usually a lot - 1/4". There is something on the head like an idler pulley to stretch out the belt a little, you should be able to push the belt in a little and not let it flutter when moving.

The encoder can get dirty and the encoder strip can definitely get dirty. Clean the encoder strip with clean IPA or vodka and q-tip, If you see dirt you have done a good thing. BOTH SIDES. . The encoder strip and encoder is a counter system where the $100 strip is just a clear piece of plastic with well printed ticks at 300 per inch. The encoder on the head of your laser shines an LED through the strip as it goes by. It has a sensor and the sensor send blips to the mother board. This system is like you counting poles holding up guard rails as you pass them in your cars. If one tick is rubbed off or not differentiated from the next - the internal counter gets misaligned. The head does got to inch #2 on the x axis, it goes to the 2400th blip.

Encoder strip are old school, but most inkjet printers use them as well. Especially the large format ones.

So to check you encoder strip, draw finely detailed things on various x coordinates at different runs. Make them long so that the head goes over potential missing ticks several times. Hopefully you will see misalignment as the items are drawn further down the y direction. If you see them in one side more than the other, you can assume a tick is screwed up. The head also jumps a little as it passes a tick like this.
Try one test pattern in the far right, far left and center. A test pattern should be something with a lot of vertical lines like boxes or vertical lines.

If all the test patterns look good, then try your over printing on different areas of the x axis.

Since your x motor was replaced, you were mucking around with the belt and the head in the process and that means you touched the encoder strip. You probably greased the rail which means you could have grease the strip accidentally and then that grease could be in the encoder head.

They are sold at US digital if you want to solder a new on in and save a few bucks.

These don't usually go wrong though, but cleaning then is a fine art. Just easier to replace as it will rule out an inexpensive item.
Encoder is $30. If a new ones fixes the problem, clean the old one using your ingenuity (keep in mind the encoder lens is plastic and fragile) and save for rainy day.

The encoder strip is north of $100 bucks.


Once you narrowed out the encoder guys, you can tackle the electrical connection, but that worked before your motor replacement (ribbon cable), Which leaves a slipping belt and a motherboard issue. If belt is loose, cut one more tooth from the belt and reattach to the head using those hex bolts. If the belt is too tight, you removed too many teeth, it should be tight but not enough to see you bicepts flex when pulling the belt to the attach point. If it is the original belt, and it worked before, you have to remember how many teeth were clamping to the head before your repair and repeat. Pictures before always help.

You can do this, good luck.