View Full Version : More kerf while cutting than before

Henri Sallinen
08-07-2014, 9:02 AM
Hello once again!

I just noticed that my laser is cutting more kefr than before. I noticed it while cutting 5mm thick wood. I have a few samples from before and the kerf is much more angled now than it has been on previous pieces. Settings havent changed and the alignment is also same.

The direction of the kerf goes from top of the laser bed towards the bottom, so the upper side of the cut line kerfs inwards on the material and the side nearer to the bottom of the laser bed kerfs outwards of the cut line.

Any ideas what could be wrong?

Thank you!

Mike Null
08-07-2014, 9:23 AM

My first thought is focus. Second is beam alignment--all optics.

I haven't experienced this nor heard of it before so I'm just making fairly obvious guesses.

Henri Sallinen
08-07-2014, 9:38 AM
My thoughts exactly. So I've checked the beam alignment and they all point almost dead center to the aligning tool (the red dot points to the center and the beam hits where the red dot hits).

I'll have to make a few tests with the focus, but I'm not sure how it could be wrong since I don't use autofocus (only the manual tool).

Scott Shepherd
08-07-2014, 10:41 AM
You might check the optics all the way upstream. A dirty mirror at mirror #1, 2, or 3 can cause that.

Martin Boekers
08-07-2014, 1:12 PM
I've noticed that issue myself...it seems somewhere along the way I read that there is a way to adjust how perpendicular the beam is to your substrate.
I'll have to do a bit of research..

Henri Sallinen
08-08-2014, 3:05 AM
Scott: I'll have to check the other mirrors and report back.

Martin: If you find anything, let me know! I'll do some research myself also.

Henri Sallinen
08-08-2014, 7:43 AM
Checked the mirrors and there was nothing out of the ordinary. I did a few tries focusing in the middle of the material and this seemed to help a bit, but still I'l like to believe, there could be a way to align the beam more perpendicular to the material.

Steve Busey
08-08-2014, 8:43 AM
Is perhaps your manual focus tool out of adjustment (maybe dropped on the floor once)?

If you have a 2" focal lens, see if your lens-to-material distance is 2.0".

Martin Boekers
08-08-2014, 9:25 AM
One other thing to check is that the I-Beam and table are level to each other.

You can test this by using the manual focus device.

Put it place, turn the x-y axis off so you can move the lens assembly.

Manually adjust the focus so the manual device is just touching the table

Now manually move the lens assembly throughout the table and four corners

If the gap is consistent then the table and I beam are level... if it's not you will
have to level the table to the I-Beam. If that's the case Epilog can run you through
that procedure for the machine you have.

Kevin Gregerson
08-08-2014, 12:53 PM
Try pulling back the focus a little. Usually when the kerf is wider at the top than the bottom you've got it too close to the material.