Inconsistent laser cutting results

Laser
#1

Hello!

First time using the laser cutter and I’m having a lot of inconsistent cuts. The forum doesn’t let me post images, but each of these should be an identical copy of one another. However, there are differences between .5 mm to 1 mm. I ran the blitzen laser on 20 mm/s on 55%. There are also some scorch marks, so I’ll try it at a higher speed/lower power in the future.

I focused the laser using autofocus and sticking a piece of masking tape on my material as it is a bit transparent.

I’m really not too sure where I am going wrong here and am trying to problem solve. Does anyone have any suggestions? I’m pretty new to this so I’m not sure where I went wrong or if a mm or 2 of error is normal for this laser cutter.

#2

I didn’t remember Blitzen having autofocus. Is this new?

#3

Not sure if it’s new, but on the control panel on the actual laser cutter, there is an autofocus feature when you open the main menu by pressing the middle button on the navigation buttons

#4

The “autofocus” might not do what you think it does - it’s just the IR sensors on the side of the bed that will raise the bed to a close distance - it still requires manual focusing of the barrel initially:

This is in contrast to the autofocus on the Fusion which actually has a touch sensor on the head. There are no sensors on the thunder heads.

The results you’re describing sound like you’re close to in-focus, but it’s just outside the primary focus zone and the variations as the head moves around are causing it to go fully out of focus.

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#5

My guess is the “autofocus”; as stated above you will need to manually focus the tube with the manual gauge [one side is for etching (rastering) the other for cutting]. The piece you’re cutting also needs to be flat, the laser head will not move up/down to keep the beam in focus.

I have also gotten scorch marks from the laser hitting the honeycomb support under my piece and burning the underside. To combat this, I have typically lowered the power [or increased the speed] or elevate [if possible] my piece above the grid.

But I bet if you manually focus the lens tube you’ll be fine.

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#6

You’re spot on! Thank you

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#7

Yes I realized there were scorch marks on my material as well. Hopefully the protective film on the acrylic will help, otherwise I’ll probably try to raise the piece. I also realized that no matter how flat you think the material is there will be some inconsistencies, so it’s best to cut from inside to out so when supporting pieces fall, it doesn’t affect the cut.

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