Epilog ext36 inaccurate cuts

[jan dressler]

I am a new member though not new to laser cutting. I had 3 Gamata lasers for 15 years and did all the maintenance myself. In 2007 I got rid of those and got an epilog ext36 75w. It ran like a charm until January 2014. I replaced every component on it except the tube and the encoder strip. It was down for 2 weeks.

it was running fine until last week when my cuts on the y axis began to stretch and shrink eradically. I cut stencils out of 7ml sheet poly, and many have multiple overlays that need to line up perfectly with each other. There is a perimeter cut around each overlay and registration holes that enable the end user to line them while painting. The perimeters seems fine, being a square, but the design and reg marks within the perimeter is off. And even though the overlays are all on one file lined up horizontally, the stretching occurs in different places on each one. If I run the file again on top of the first cut, it will cutting differently each time.

Heres se what I have done so far:
squared up the I beam meticulously 4 times to be sure
flipped the encoder strip
replaced the y motor
flipped the ribbon cables to the cutter head and y axis
reloaded the firmware
Reinstalled the printer and driver
reinstalled coreldraw x6 (clean install)
tried all sorts of files, so I know it's not a file corruption issue

tech support is baffled as well, they don't think it's a hardware issue, I just want a working laser.

has anyone experienced this with their epilog? I'm ready to go get a trotec, but can't sell this one if it isn't working.

[Mike Null]

Jan

Welcome to SMC. Though I can hardly be considered an expert, I would first suspect a hardware issue, unlike what the techs told you.

My Epilog experience dates back to dinosaur models where the table moved in the y axis so that's not relevant but I would be checking belts, pulleys/gears and bearings for free running with no binding or slop.


Good luck.

[Gary Hair]

It ran like a charm until January 2014. I replaced every component on it except the tube and the encoder strip.

So for 7 years it ran perfectly then a couple months after a rebuild it isn't working so great any more... I can't believe it would be anything other than hardware given that circumstance. When something quits working you need to go back to when it last worked and determine what changed - seems like you have done that - before the rebuild it was fine. Just out of curiosity, why did you replace all of the parts you did?

I'm with Mike, check all belts, pulleys, bearings, rails, anything that moves, and clean then lubricate. It sounds like something is randomly sticking and causing random problems.

[Tony Lenkic]

In addition to Mike & Gary's suggestion check if encoder strip may be dirty (even small spec of dirt could effect proper position reading).

[Kev Williams]

More than once I've found Y-axis issues on both my ULS and LS900-- on the 900 I've found a drive rod that was loose, set screws on the connector sleeve wasn't tight; once the short Y drive belt was loose, once the whole Y stepper motor was loose. On the ULS the X stepper was slightly loose, which caused the motor housing to twist, which created interference within the motor which caused bumpy engraving and step-skipping. I bought a new motor, still have it since tightening the motor correctly fixed the whole problem. Right now I need to change my X-belt on my LS900, near home position the belt is stretched enough the belt teeth don't line up to the drive cog, makes lettering about 1.5" from the left too "fat". And last Saturday I messed up a large SS control panel because, earlier I was showing my NH rep the lens and its holder from my Triumph. After removing the lens, I put the lens back in, and only half-screwed in the tightening ring. So the whole 1.5 hours the machine spent etching Cermark into that panel, the lens was about 1/16" out of focus AND was just flopping around inside the sleeve. Lettering with shadows, outline borders that didn't line up, I was pretty perplexed until I removed the lens housing... Made me feel a bit less than smart!

Goofy mechanical issues like these can drive you nuts...

As for the an electrical issue causing the problem-- I've been running CC stepper-motor driven machines since 1981, and at least 99% of the time if there's an electrical problem causing erratic stepper motor movement, it's accompanied by the steppers making unusual noises-- such as occasional "thumping" noises, or semi-'grinding' noises during movement. I'm no expert on the matter, but I've always attributed the noise to the steppers getting conflicting or 'nonsense' data. The other 1% of the time, the machine will usually just start engraving a straight line in some direction towards infinity. Simply based on my experience, since you're machine seems to be doing pretty much everything "normally", I'm going with "mechanical" as your problem...

[jan dressler]

I had to raster my sheet poly to get a stencil that lined up perfectly. It took an hour opposed to 3 mins though. I then removed the poly and left the sheet of backing paper on the bed. I cut the same file as vector and the cuts were off register. Weird.
So after exhausting all possible external issues, epilog tech support is once again going above and beyond, and sending me new motherboard, y motor,ribbon cables, y combo controller board and amplifier. We r just gonna throw the kitchen sink at it and see if it works.

[Mike Null]

I know Epilog tech support has a great reputation but here they've just thrown in the towel.

So if this doesn't work what's next?

[jan dressler]

I know Epilog tech support has a great reputation but here they've just thrown in the towel.

So if this doesn't work what's next?


Well it didn't work. So now they had me turn off the autofocus and run some files. The over cutting has stopped,but the design within each perimeter is still out of alignment. Guess we will be at it again tomorrow. Tech support is really puzzled, they really are great tho. They have practically given me a new laser. We'll get it running right.

[Mike Null]

Jan

If you're satisfied that it is not a hardware issue--then I suspect the drivers.

Ask Epilog to help you remove the firmware and drivers and get their latest iterations of both installed on your machine.