Page 1 of 1
Different Focus Lenses
Posted: Tue May 28, 2019
by Colin Krebbers
Hi all,
While trying to cut 12 mm thick poplar wood I've noticed different results with various lenses.
Standard, I'm using a 3" ZnSe lens giving me clear and fairly straight cutting edges, getting through the material at a nice pace.
Once we are using a 4" or 5" ZnSe lens, while setting its focus accordingly, we are not able to cut through the same material with equal laser settings.
We are using the laser head tube, height adjustment rings, and 4"/5" lenses from Master Laser.
Looking forward to your reply!
Colin
Re: Different Focus Lenses
Posted: Tue May 28, 2019
by Gene Uselman
Colin you may want to watch Russ' videos on lenses [there is an index of his videos on the forum] Most machines I have seen are either 1.5 or 2.0 lenses and that is what I have experience with. I just googled your laser and it looks like a pretty substantial machine- is it a cabinet or flatbed?
Re: Different Focus Lenses
Posted: Tue May 28, 2019
by Colin Krebbers
Hi Gene,
Thank you for the reply and advice, I will have a look at the videos!
Indeed, it's a flatbed laser with quite large dimensions !
Kind regards,
Colin
Re: Different Focus Lenses
Posted: Wed May 29, 2019
by Colin Krebbers
Hi,
From the following video I might have find the answer to what I've observed.
Quite obviously, the spot size of the laser with a larger focal distance lens increases, simply reducing the power per square mm/inch.
Link to the video:
https://www.youtube.com/watch?v=K_dKUsY05jY
A nice side note, within the video the reasoning for me using a large focal distance lens is being presented.
You might have observed in some sense tapered edges cutting thicker material, this gradually decreases using lenses with higher FD.
A summary of the correct lenses specified for different types/thickness of material can be found from the table provided by Trotec:
https://www.troteclaser.com/en-us/knowl ... ight-lens/
Kind regards,
Colin
Re: Different Focus Lenses
Posted: Fri Dec 27, 2019
by Dave Vigness
Something else I discovered in emailing with Russ, the difference between cutting and engraving setups. I didn't realize mine was set for engraving, with a more than 19mm gap tip to work surface. Not getting enough airflow to keep the cut clear for good cutting. Getting a set of tips to get my gap down in the 5mm to 6mm range. I'f you're not close to the work you're fighting yourself.