What is the best kind of focusing lens, a regular lens or a meniscus lens?
II-VI Infrared lenses are superior. Meniscus lenses are what I recommend.
“Meniscus lenses are designed to minimize spherical aberration producing a minimum focal spot size for incoming collimated light.”
http://iiviinfrared.com/CO2-Laser-Optics/meniscus-lenses.html
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I use ii-iv lenses exclusively in my lasers, and we have been using custom manufactured lenses from ii-vi infrared for the Beam Buddy high resolution laser heads that we sell. I can not speak highly enough about the quality of the i-vi lenses.
Have any of you guys tried Russ’s SarbarMultimedia compound lens system?
Cloudray Compound Engraving Nozzle Set Lens Diameter 18mm 20mm with Compound lens for Laser Engraving Machine https://www.amazon.com/dp/B07KC58TDQ/ref=cm_sw_r_cp_tai_lxACEbR7RFSKH
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Yep. I ordered one and have tried it and it seems to work great.
I thought he had a problem with the lower lens being damaged by the reduced beam size from the first lens. Has that problem been solved?
I hadn’t heard about that. Any link to a site where I can read about it?
Here are some results
Photo of the dog above is about 5 1/2" across.
I saw it on one of his videos, shortly after he installed the compound lens (which did give him excellent results) he noticed the focus abruptly changed badly. When he took the lens out to inspect, he saw that the lower lens had a large circular dark spot in its center that could not be cleaned. He guessed the beam power entering the second lens was just to much for the lens material to handle.
Maybe he was using a cheap lens for that first test and a better quality lens can cope better.
Interesting. I’ll have to see if I can find that video. The lenses that came with mine were both from II-VI.
The lens getting damaged is one of the drawbacks of the design. The Beam Buddy high resolution laser head I sell does not flat pack the lenses like Russ’s, and uses custom manufactured USA ZnSe AR coated meniscus lenses that have an air gap between them in a solid aluminum housing. The lenses are rated for 150W power handling and stay very cool with the air assist on and the air gap between lenses.
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These are for CO2 lasers? What’s the thread size? 22mm?
We have different size adapters for different machines. If you are interested, head over to https://hub.beambuddy.xyz
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The size of the nozzle correlates with the proximity of the two lenses. Not all machines experience problem referenced.
Cheers
Sas
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Here you can find the elaborate list with descriptions of all the video’s of Russ.
perfect for reference
@Grumpy_Old_Man your products are very nicely built. I especially like that it’s machined/built out of metal.
The results in your sample are stunning.
Our two head big Green Machine is due to arrive in Los Angeles Port from China Tuesday and with a bit of luck we should get it delivered in Portland 3.28. I am very interested in upgrading the engraving head so I’m doing research on the nozzles. Until your post @Grumpy_Old_Man I did not know that there was another option over the Russ/CloudRay upgrade.
Do you have a comparison between your beautiful nozzle and Cloud Ray to show the difference/benefits.
Cheers
Sas
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My problem is I have 12 mm lens. HARD to find but I did, at Cloudray Laser and ordered a 12 mm CVD ZnSe meniscus lens, until I can find a new laser head that I can use. My laser head attaches different than most, it’s a Samger 80 watt. LightObject was no help at all, here is a picture
anybody know of a replacement head I could use so I can get a larger lens?
Maybe just change the entire body that attaches to the gantry. Plenty of options if you can go that route.
Does this work?
US $23.50 6％ Off | Will Feng Laser Cut Head Fit 45mm Outer Rail Mirror Dia 25mm Lens Dia 20mm FL 50.8/63.5mm For Co2 Laser Cutter Engraving Machine
That looks pretty good BUT it has no air assist and no red dot laser holder. THANKS for the info though!
It does have air assist (pictured) and the red dot pointer is easily attached to the head’s threaded end.
I removed my pointer. Those pointers are pretty useless and never accurate. I’ll mail you mine if you want it. 
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That looks like it’s made to ride on some kind of V rail with those rollers on the back side. Wouldn’t mount to his linear rail block. ??
Have you taken the head off to see how your round tube is attached to the bottom of the block? Possible to maybe just replace the tube? What’s the bottom side look like?