How To Adjust Epilog Rulers?

[David Graham]

Hi,

This is probably overly obvious, but I have been playing with the top ruler on my Epilog Mini for the past couple of days trying to correct an accuracy issue. It's pushing material down by about 1/32". So a 1"x1" block piece measures fine left to right, but is 1 1/32" top to the bottom.

I contacted tech support by email and they said to run a piece of tape an inch from the top. Engrave it across, measure an inch from the engraved line toward the ruler. Then, loosen the screws and move the ruler.

Sounds easy enough, which actually I had tried something similar prior to calling tech support. My machine is about 5 years old, so I don't know if they have changed in this regard, but I ran into a problem with actually moving the ruler.

The middle and right screw are in a slide groove so the ruler can move. However, the left screw is not, so that side won't slide back and forth. If I move the other side, then the ruler is no longer parallel to the material.

So how can I get the entire ruler to move back. There has to be a way. Otherwise, what's the point of having the middle/right screws in a groove?

Initially they told me to reposition the x/y axis, which I did and it should engrave properly now, but it's the ruler that's the problem as the piece is measuring longer down the table, which wouldn't have anything to do with the home position.

Thanks for any help.

David

[Doug Griffith]

When cutting a 1" x 1" square:

If it's "A", you've got issues not related to the ruler position.

If it's "B", then adjust the home position up 1/32".

Rotate these suggestions 90 degrees depending on the affected axis.

The rulers are slotted on the middle and end to align the squareness to the gantry.

[Gary Hair]

The easiest way to ensure your rulers are perfectly aligned with the laser is to do the following:
1. Remove all rulers
2. Using trophy tape attach two 1" wide pieces of 1/8" acrylic to the laser bed, the acrylic should straddle the line that is approximately where the x and y axes should be.
3. Draw a line in Corel at 0 x and along your y axis
4. Draw a second line at 0 y and along the x axis
5. Cut the acrylic
6. remove the acrylic where the rulers mount
7. Place the rulers against the acrylic and fasten them down

Since you just cut the line with your laser, it will be aligned with the x and y axes. If you can't live with the .008 that the laser kerf removed from the acrylic, you can shim the rulers .008 from the acrylic and you'll have them aligned as close to perfection as you possibly can.

Don't bother trying to cut tape and align your rulers to it, it's just not very accurate.

Pictures attached to give a visual of what I explained.

Gary

[Dan Hintz]

I'll modify Gary's suggestions with what I do... same thing, but skip the acrylic. I move the rulers, lay down painter's tape, and etch right through the tape. Remove the unwanted tape on the top and left, slide the rulers up against what's left (not completely, otherwise you'd be cutting the ruler next time), and tighten.

Done!

[Doug Griffith]

I don't think he has a problem with how to adjust the rulers. He does not have enough adjustability in the hole closest to zero to compensate for the home position offset. If that is his problem. From his wording, it sounds as though the 1" square isn't shifting but stretching 1/32" on one axis.

[Dan Hintz]

Ah, I should pay more attention to the original post than the subsequent replies...

I would have thought adjusting the home position would solve the problem. If it didn't, I guess I'm not clear on what the issue is...

[David Graham]

Thanks to all. I appreciate the response. I am not sure if I communicated my issue initially, but Doug seems to have deciphered my code in his last post. :)

If I have a piece that really measures 1"x1" (before any engraving or cutting)...the ruler on the top shows it to be 1", but the ruler on the left shows it to be about 1 1/32". If I rotate the piece, where the side that measured against the top ruler showed 1"...it now shows 1 1/32" against the left ruler.

This tells me the ruler at the top is slightly lower than it should be, right? I have no idea how this happened.

So I get that I need to adjust the ruler. The problem I am having is basically what Doug mentioned.

I have no idea how to adjust the ruler on the left side, closest to the home position. It has no wiggle room. The other two are able to slide, but if I move it with the other one stationary the ruler is no longer parallel to the material.

Thanks again for any direction.

[Doug Griffith]

I just checked my machine (Epilog Mini) with a set of calipers and it is also off around .05". In all honesty, I've never used those rulers for anything more than guestimating positioning of material. If you want accuracy, create a fixture that wedges in the up left corner (0,0) and then use the laser to etch the measurements you need onto that fixture.

[Doug Griffith]

The issue.

[David Graham]

Thanks Doug. I don't really use those either, although it is nice to gauge. As I said, I repositioned the x/y axis so it should engrave correctly.

Two reasons why this is an issue (other than my OCD =).

One, I am creating poker chips from wood and, unless someone has a better idea, I plan to engrave the designs on one side of a sheet, flip the piece top to bottom, engrave the designs on the second side, then cut. The design is spaced out so in theory the designs should be perfectly aligned.

I thought about cutting circles out first & dropping them in a template so they are all in the same location, then engrave. The ruler issue would become moot at that point. The problem then becomes lining up the chip on the second side when I flip it over to engrave. I want them lined up and the only way I could think to do it quickly and easily was to engrave on both sides, then cut. Any ideas there would be appreciated as well.

Anyway, after testing that process I noticed the engraving was off, which is what made me notice the ruler issue.

Which brings me to my other issue with it...I started thinking if my machine only engraves 12x18 and I have a piece that needs to be engraved edge-to-edge and the piece is 12x12 (up to 18"), then will it engrave to the edge if the material starts further down on the table?

Or will it stop engraving 1/32" from the bottom? I mention if the piece is 12" or larger because then I wouldn't be able to rotate and engrave across the table.

[Gary Hair]

David,
I have used alignment pins before to keep registration on a two-sided piece. It's easier in my cnc router because I can drill the holes in the fixture and the blanks using the router itself. With a laser you can mark two places on a fixture to drill holes and insert pins, then laser cut corresponding holes in your blanks and place the blank on the fixture. When you flip it over you place it on the pins and it is perfectly aligned, or as perfect as the holes that you drilled for the pins anyway.

Gary

[Doug Griffith]

For the poker chips, I'd engrave, flip, engrave, then cut. You might want to cut the perimeter of the board with the laser (cut line in the same file as the parts) inset about .25". Leave the perimeter in the laser and only flip the internal piece.

As for edge to edge, that's a lot of confidence. If you attempt that, the ruler measurements shouldn't have anything to do with it as long as the home position is at 0,0 to the table.

[David Graham]

Thanks to everyone for their help. Great ideas on the alignment. I hope that as I learn more I can give back as well.

[Scott Shepherd]

I must be missing something, you need to move your XY home in the control panel, and then it'll line up fine.

The procedure is in the manual. I wouldn't even consider moving my rulers. You don't have to.

Or either I'm missing something.

I know when we had our Epilog, I moved that setting several times, doing the exact test that you are doing. The alignment procedure even gives you that very same test.

[Dan Hintz]

Is the 1/32" offset consistent all of the way down the table, or does it continue to grow by 1/32" with every inch you move down?

If the former, a home position reset should do the trick. If it's the latter, you should be able to tune it out with the driver.

[Doug Griffith]

I must be missing something, you need to move your XY home in the control panel, and then it'll line up fine.

The procedure is in the manual. I wouldn't even consider moving my rulers. You don't have to.

Or either I'm missing something.

I know when we had our Epilog, I moved that setting several times, doing the exact test that you are doing. The alignment procedure even gives you that very same test.

It's actually very simple. The laser is fine and the home position is at 0,0. It's the ruler's measurements that don't line up. You'd think it would be as easy as resetting home, loosening the rulers, then doing the tape thing. The problem is that the ruler's adjustability does not allow him enough play to shift the ruler along it's axis to correct the offset. The other axis' ruler should do it but he says his far left hole is not a slot (mine is so I could adjust it if I wanted to compromise my current fixtures positions).

[Patrick Licata]

I had a similar issue with adjusting my rulers on my Epilog Mini. The ruler holes were not all slotted so they could be adjusted. I called Epilog to inquire about this and they sent me new rulers that had slotted holes for adjusting.:)

[David Graham]

Thanks Patrick. They never offered that as an option. I will have to inquire.