Laser Cutters

[Rewound]

I now have access to a 60w CO2 laser cutter.

Anyone know how suitable this would be for cutting hardwoods that are 5mm thick. need a good clean top cut (not bothered if burnt a bit underneath) Been told not allowed to use above 70%. power

What speeds / passes should I be experimenting with ?

 

[Torx]

‘Hardwoods’ is a bit vague…just like a saw or chisel it will cut balsa a lot quicker than oak. You just need to experiment, you might find certain materials it will barely penetrate. Every laser is a little bit different too, so there will be a variation even if someone with exactly the same machine recommends settings. You want the fastest speed possible that will penetrate the material to reduce charring on the edge, more resinous materials will give you a burned edge more easily. Stay nearby due to the fire risk.

 

[akirk]

my 40w (non CO2) laser will happily cut twice that thickness with no issues...
I usually put in a bit of scrap - draw a bunch of circles (experimenting seems to suggest that more passes are needed for curves than straight lines), and then set each at differing levels of power / speed / passes etc. - run the test piece to choose which gives the best result... I do this fresh for every new type of wood as it changes so much

 

[Rewound]

Have been experimenting a bit with different woods, it varies so much! .... I have a mahogany I could barely get 2mm into, where as a walnut, easily 7 or 8mm with one pass at 65% power. There is a lot of experimenting to do with power and speed (and then how many passes)

One thing I have just thought of (and I won't be near the laser for a few days to test).. The laser we have needs to be focused 18mm above the surface. However what happens if after the first pass (and lets assume it has burned down to 2.5mm) if I raised the bed 2.5mm so as the new focus would be at the bottom of the cut (even though the cut is only 0.1mm wide ?

 

[akirk]

every laser is different - mine has the option to focus just sub-surface to help with cutting - others don't, so you need to check with the manufacturer.

 

[Rewound]

every laser is different - mine has the option to focus just sub-surface to help with cutting - others don't, so you need to check with the manufacturer.

Does yours focus automatically ? Mine is manual so it would be easy to set it 2 or 3 mm too low.

or do you mean something else but focusing sub surface?

could focusing too close cause damage to the laser ?

so many settings to play with and not enough time.

 

[Esqy]

My laser (Ortur branded) came with a little metal cylinder (Focal gauge), which you pop on the wood and lower the laser module to it, which gets the right distance.
Also, I have a file I made on Lightburn (Highly recommended software for lasering) made for testing the power and speed on different bits of wood, and another part of it to test how many passes to get a clean cut.
I took the photo before I hooked it up to the compressor, so some of it is a bit burnt. (I also adjusted the settings for the text on the second go)

Oh, and you will always get burn marks, but nothing a little sanding can't handle.

 

[akirk]

Mine is fixed focus and you can move the head up and down (XTool Pro D1 20w)

Second the value of lightburn (which will auto produce test patterns for you…)

 

[Esqy]

Lightburn is worth every penny. Using it during the full-function trial was a dream compared to the other free programs out there.
It was only after I made those test patterns that I found out Lightburn can do it for me... Ah well!

 

[Fireburst]

5mm should be no problem. Use air assist if you have it and try a few passes on a lower setting for a better result.