[mooreaa]

Hi guys,

I'm very new to laser cutting.

I'm trying to cut 1" thick poly foam on my laser and although the laser slices through it like butter, I am having an issue with the cut being very angled. The top of the cut is ~ 0.5mm wide but the bottom side is like 1cm wide!

I think this has to do with my lens setup and I would like to know what can be done to change the cone angle. Do I need a different focus lens? A different head?

Here is the laser head that I have: https://www.dropbox.com/s/o71z53dcf1...ss%20Dot-2.JPG

Appreciate any tips.

[ozstockman]

If you need a perfect straight cut on such a thick material lasers are wrong tools for it. Even if you go with 4" lenses you still won't get straight cut. That's a nature of laser cutting. As an example I cannot get straight cut on 1/2" with with 3" lenses. Your foam is two times thicker and I do not think there any lens that can keep focused laser beam straight 1".

You can check this page for depth of field definition Frequently Asked Questions about CO2 laser lenses for cutting As you can see with 4" lens you can get only 7.5mm DoF It means that material thicker than 7.5mm won't be cut with a straight cut anyway. I have found that normally 3" lens produces not prefect but still good results only up to 9mm thick material. 12mm, 16mm and 18mm thick material are still acceptable for my products and I cut them as well but it makes their edges in hour glass shape.

[thunderlaser]

hello，mooreaa
If you want to cut 1'' or even more thicker foam ,you should use the 4'' laser head
But first you should sure the optical path verticality first ,
the best focal distance is that the distance between laser head and the material
you should lower the focal distance 1-2 mm on this basis
for example ,if you test the best focal distance is 10 mm ,then you should adjust the focal distance to 8-9 mm
and you should meanwhile use the air compressors or oil-water separator ，it will make the cutting effect better
We have tested before, and really can cut through it
If you have anything unclear ,just feel free to ask us

Hi guys,

I'm very new to laser cutting.

I'm trying to cut 1" thick poly foam on my laser and although the laser slices through it like butter, I am having an issue with the cut being very angled. The top of the cut is ~ 0.5mm wide but the bottom side is like 1cm wide!

I think this has to do with my lens setup and I would like to know what can be done to change the cone angle. Do I need a different focus lens? A different head?

Here is the laser head that I have: https://www.dropbox.com/s/o71z53dcf1...ss%20Dot-2.JPG

Appreciate any tips.

[EXLASer]

Hi Mooreaa,

In the past few months , I was cutting the poly foam as a hobby , and did some samples as while to memory the Halloween and the following Christmas .
Most of them are 15mm thickness and one was 25mm more or less that caught my eye , bes the job seems acceptable ,not too much difference between top and bottom side as you do. But the top cut is still a little bit bigger ,it is hard to avoid ,as the poly foam is easily to melt .
I draw the vector from Internet and cutting the job , ends good performance and stick them on samples wall .One was taken away by a visited customer ...

To cut the poly foam , big air to blow is quite important .The foam is flammable especially when it run into corners . Power should be set very accurate as well ,or it's catches fire immediately .
The third thing I thought is the laser tube and focus length . 150W tube is not perfect ,although it is professional in cutting ,bes the spot is so big on poly foam.
I use 80W and 63.5 mm focus lens at that time . You can see by http://www.cnczone.com/forums/exlas_...r_machine.html

Thanks and br,
Ms.Mary