Convex lens question

[Craig Matheny]

Ok this is a good one at least in my mind.... Ok I have an epilog mini 24 the lens Assembly goes holder o-ring lens curve up and bottom plate this was confirmed yesterday at the MBN show. Got home and as I thought of coarse I have mine all wrong so I changed it to lens Assembly holder o-ring lens curve up and bottom plate, did the focus corrections and started to run with it. Cut terrible cut parts are hard to get apart and it was frustrating played with focus and all. So this morning I put it back to lens Assembly holder lens curve side down o-ring and bottom plate adjusted the focus and it cuts great and the pieces seem to fall out a lot better and did not even do a cleaning. My thought is it is creating a wider cut kerf so the parts are looser but why does it cut better? And having it in upside down will it damage anything?

[George M. Perzel]

Hi Craig;
All mine are curved side (convex) up but lens holder is machined to only let it be inserted that way so really cant test it but would expect your kerf would be wider when inserted the wrong way.
Best Regards,
George
Laserarts

[Dan Hintz]

Convex side up is the proper orientation. If it wasn't cutting well in that orientation, you're focusing point was incorrect.

[Craig Matheny]

Convex side up is the proper orientation. If it wasn't cutting well in that orientation, you're focusing point was incorrect.
I am pretty sure the focus was good did all the steps to check it and adjust and did adjustments with it up and down all last night. With that said and no need to debate it the real question is will it hurt anything? Right now it is cutting cleaner and faster and the parts drop out easier from the cut so the wider kerf I get will measure it latter. But will it damage anything?

[Rich Harman]

According to this; http://www.lasercomponents.com/fileadmin/user_upload/home/Datasheets/lc/applikationsreport/lens-theory.pdf

"The error of misorienting a plano convex lens approximately quadruples the blur."

[Dan Hintz]

"The error of misorienting a plano convex lens approximately quadruples the blur."
That's it, in a nutshell. I discussed this in more detail in an earlier thread... maybe a year ago, give or take?

Will it damage anything? No. But it's a waste of power, and reduces your ability to focus as finely.

[Craig Matheny]

Dan being you are awake on Sunday then maybe you can tell me if there is a better way to set the focus. When I got the new laser tube and everything they had me set the focus by.... making a 2 x 3 solid square in Corel and sending it in raster mode to the laser and a slow speed then raise and lower the table unit you get the brightest light and you are in focus so I do that to set focus the adjust the focus gauge. Is there a better way or a more accurate way this seems like guessing with a precision interment.

[Dan Hintz]

Dan being you are awake on Sunday then maybe you can tell me if there is a better way to set the focus. When I got the new laser tube and everything they had me set the focus by.... making a 2 x 3 solid square in Corel and sending it in raster mode to the laser and a slow speed then raise and lower the table unit you get the brightest light and you are in focus so I do that to set focus the adjust the focus gauge. Is there a better way or a more accurate way this seems like guessing with a precision interment.
Getting the brightest light doesn't mean it's the best focus. Your best bet is to take a strip, say 10" long, of anodized aluminum. Lay one end on the table and the other end on a block of wood 1" high. Set the table height for a substrate 1/2" thick. Engrave a vector line along the strip... it helps if you engrave hash marks at 0.25" increments (or whatever looks good to you). If your focal point is set correctly, you'll get the sharpest/thinnest line halfway up the strip. If not, determine where the sharpest/thinnest point is and adjust your focus up/down accordingly.

[Craig Matheny]

Thanks i think I have the concept

[Mike Null]

Craig

Do you know what the focal length of your lenses is. They usually come with a 2" lens unless you've specified a different length. There may be a drawing in your user's manual for a focusing tool you can cut out of plastic .

[Craig Matheny]

It is 2" and the way I did the focus is the way epilog says to do it little frustrated when something works better put to geather wrong then when you follow the directions