Which is the right way up for a CO2 Laser Engraver lens?

[@manchurob6432]

Have been lasering for 7 years now, and that is hands down the best explanation I have seen yet. Well done.

[@SmokeMirrorsVideos]

Thank you.

[@philscraftcorner]

Brilliant explanation, there are so many arguments for both ways on this the most common 'that is how it came in the machine' especially when the machine is a k40. I did some testing both ways and it was clear which way gave more power and a cleaner crisper line when engraving.

[@SmokeMirrorsVideos]

Yes, that was my motivation for making the video. As a parts supplier I of course order lenses directly and I know I am buying plano-convexed lenses, and these are used most commonly in cutters. When it comes to a K40 for instance, there isn’t any budget left for the manufacturers to “experiment” they use industry standard stuff if a machine costs only $300 and the seller and manufactures all need to make a profit... they might not be using the very best parts or taking care over the quality of assembly.

[@philscraftcorner]

I'll definitely be checking you guys out when I need to replace my mirrors and lenses again

[@kimnielsen9320]

Thank you for a very precise explanation of what is going on when the laser light is going through the lens

[@gtcollection6933]

Educated explanation and demonstration. Thank you for taking the time, S&M.

[@n1vg]

Bless you for putting the answer in the first 10 seconds!

[@tttuberc]

Very clear & nice demonstration. Thanks

[@rickborbons4398]

...very informative...I'm a new laser owner...learning as I go along...thank you for this video!

[@LaserEngraving911]

Super neat demonstration! Thanks!

[@grimreboot]

Excellent explanation Dominic!

[@SmokeMirrorsVideos]

Thanks Ben!

[@mjb6714]

Fab video - Thank you for the clear and concise explanation.

[@SmokeMirrorsVideos]

Glad it was helpful!

[@sofloemir]

Thank you so much for this! I had no idea there was a proper way. Explains why I'm having such a hard time cutting through stuff lately... I can't wait to leave work and check what orientation I have mine. I'm sure it's backwards because my machine just started cutting horribly out of nowhere!

[@SmokeMirrorsVideos]

Having the lens the right way up should help certainly. It can be tempting to jump to a conclusion about why you might have had a loss of performance. But the chances are as high that your performance has dropped due to beam alignment or dirty optics. Check my video about basic alignment check as well as the video on downward alignment.

[@sofloemir]

@@SmokeMirrorsVideos alignment seems great. I just cleaned lenses but I will clean again. I will sure to check other videos!

[@SarbarMultimedia]

This maybe quite and old publication but I suspect many new laser users will be attracted by the title. I have been "playing" with lasers for 7 years or more as a retirement activity to keep any remaining grey cells exercised. My goal has been to educate myself on all types of laser technology and to uncover the real scientific facts behind the many misunderstandings and myths that pervade the rapidlu growing user base. What you are demonstrating is exactly how the Greeks, Egyptians, Romans, Galileo, Kepler etc right up to the modern day would have desribe the action of lenses. Light has not changed for ever, so this RAY theory to descibe how lenses function is still used to design lenses today. BUT, , anyone born before 1965 could never have imagined the weird concept of coherent light (the laser beam) . Yes we have special lens materials (zinc selenide and gallium arsenide) specifically designed for our laser wavelength, however they are not designed for our machines. Instead, they are still designed as if they were being fitted to a telesope or camera. . Lenses are designed for focusing NORMAL ,random uniform light (usually IMAGES). The laser beam is far from NORMAL and is focused with the sole purpose damaging material with its INTENSITY property. Its relationship with lenses falls outside the boundaries of standard lens theory. Without making this too long, what lens manufacturers specify is correct for normal light optical applications but is meaningless for laser applications. Start damaging materials with a laser beam and you will soon discover that the focal length is not a fixed property, Different speeds , powers, materials and lens shape or orientation will cause the focal point to vary by as much as 5mm. because the INTESITY focus (that causes material damage) is NOT a fixed property and may be several mm away from specification. You must understand that there is no crtitcism of your video because you are only broacasting know "facts" to a possible new audience, and that is praisworthy. I have spent more than 4 years studying how lenses really work with laser beams and its not the simplistic model that you understand. There is no right way for a lens to operate . Yes convex side up is how lenses are designed but when used the wrong way you can exploit laser beam properties that lens manufactures are just not aware of. Look at this 30 second video wth a lens used the wrong way up and ask yourself "how is this possible?" The right way for a lens is the way that gives the best performance . It may differ between cutting and engraving. I have a collection of almost every lens type/focal distance and about 3 years ago I did extensive testing to compare lenses in the hope that a pattern of data may emrge that would help answer the question I just posed. "What is the mechanism by which lenses cut?" especially deep parallel cuts as you have witnessed in the short video above. I have collated all those lens test results and sumerized the data to answer some age old myths. I am happy to share that data (a pdf file) and any other knowledge that I have acquired You or nyone can contact me privately through this contact form forms.zohopublic.eu/ndeavorlimited/form/K40XtreeemLaserCutterContactRussSadler/formperma/k2Cn0QN5ChpazfTMAUw25lZ-FKpjZa96TQWHjv3ntOg Best wishes Russ

[@frankherrmannweilburg4436]

this was what i looking for, very good explanation......thanks a lot

[@stevejelias]

Thank you for your wisdom and clear advice on lense placement. I have a OMT laser that I just upgraded from 80W to 150W In an effort to keep this short I'll just say refitting the 5 foot 6 inch tub into the very tight and short housing was a nightmare. Because of the limited room I had todo some significant cavity surgery to get my lense assembly placed properly. However, somewhere in the alignment process a slight angle was introduced and I'm about to go crazy trying to realign everything so that the X and Y movement does not cause DRIFT in the laser position. HELP! Is there a systematic way of making sure all mirrors are level True once aligned? I would be so grateful if you produced a video on this. None of the ones I've seen get into the nitty-gritty of fitting a larger tube in and getting all the alignment correct. Signed Humble 🙏🏻

[@hullinstruments]

I would absolutely love to see more videos from you regarding lasers and optics! There’s a huge lack of that contact on KZbin… And It’s such a huge topic! Laser and optics takes most of my time and money set aside for hobbies 😁 It really is the golden age for electronics and technology equipment! . You can buy decommission medical, government, and industrial lasers/optics… For pennies on the dollar. I picked up a very nice laser/optics table and “breadboard”…..all of the mirrors, mounts, and lasers from a big government auction for pennies on the dollar!

[@SmokeMirrorsVideos]

I will try to do more, I especially would like to produce more basic guides for beginners and on materials.

[@Rabbitte2008]

Outstanding video!!

[@partryklezuch1702]

I will try this with my 350 w laser Hope the quality will be better i have only Problems with this Eurolaser System

[@kyleesproul6902]

Just checked my lens to clean it, first time since buying the machine (only used a handful of times) the lens was installed with the flat side up? Should I contract my manufacturer or should I assume this was just installed incorrectly? It’s been working fine, but I know you said it will work either way.

[@andrewdavies9976]

Thanks for the video .

[@Laserengraving_]

Hi, I would be interested in a video about viewing panels for C02 laser machines as some seem to be fitted with what looks like standard clear acrylic but is this the case or are they really specialist panels? Thanks for your excellent video on lens orientaion.

[@oldNavyJZ]

The key takeaways are 1) it doesn't really matter and 2) it took extreme exaggeration of the effect of the direction in order to simulate a slight and still barely imperceptible difference. If you are having problems with your laser, the problem is far more likely to be involved with alignment from mirror to mirror through the system.

[@SmellyCatCreations]

Really useful video

[@tweedie005]

Thank you for the helpful video. Does it matter which side the washer is? On my machine it's between the lense and the holder. In your video you had it between the locking nut and the lense.

[@mikesamples2534]

In the video the purpose of the washer placement is to cushion the lense from the turning/grinding force of the lockring into the glass. Placing the washer on the output side of the lense could also introduce an unwanted tilt to the beam when the lockring is threaded.

[@ThingEngineer]

What are your thoughts on touching the lenses considering they are often coated in thorium chloride?

[@SmokeMirrorsVideos]

Hello Josh. There isn't a simple answer here. The lenses mostly supplied with cheaper CO2 water cooled laser cutters are made from Zinc Selenide ZnSe, the manufacturers data sheet does not include thorium chloride. It lists an AR coating, which simply means anti-reflective (and does not hint at the chemical). It is relevant that occasionally AR coating is applied only to one side of a lens making the lens orientation even more important. Often ZnSe is coated with a micro thin layer of polypropylene. Put simply, it is always best to avoid handling optics with naked fingers for a number of reasons, touching optics should always be kept to a minimum. In practice and practically speaking, for most CO2 laser cutter users, it's not really a problem.

[@jjames3793]

ZnSe is even something your not supposed to touch with bare hands and even when cleaning up and disposing of broken ZnSe lens your are "supposed to clean up with a wet paper towel and then put in a sealed container and shipped to manufacture for proper disposal so it doesn't get into a landfill and into the groundwater. and also not supposed to breathe in any of the dust that's created whenever a lens breaks but even breathing in microscopic glass particles can give you lung cancer to. even without being water-soluble and radio active. But if i had to guess thorium chloride would probably have the same handling and disposal.. Tho best to not touch a lens to keep it from getting dirt or oils from your skin on it. whenever possible. Ive even been using gloves to handle my focus lens for the co2 laser. but mostly just because i found they slip out of my fingers a lot less.

[@adotindustry486]

You are the best!

[@ClintonCaraway-CNC]

Get your lenses from American Photonics. They come mounted correctly and work perfectly!!

[@lifegamero]

Hi ! tKS!!! This video help me to understand how LIGHT behave when laser colide witH lens... I want to make a video with this video as educative resource . Can I have your permision to use your video in my video ???

[@FilipeCampanico1]

Please help. Bought a cloudray adjustable laser head. I aligned the mirrors, all went smooth, the problem is when inserting the lens on the laser head tube it no longer marks. New lens and mirrors, what could be the problem? TYVM

[@SmokeMirrorsVideos]

It sounds like it is still an alignment problem, downward through the lens. However please try my free community forum community.andmirrors.co.uk KZbin comments isn’t a good place for providing advise!

[@skyview6994]

Was looking for an explanation, you sir did very well...thank you

[@cyberlizardcouk]

i find that because the lens is small i struggle to know which is the flat side and which is the curved. Is there an easy way to tell?

[@SmokeMirrorsVideos]

Sounds like you have the 12mm OD lens common in some K40 machines and other lighter equipment. There is usually still a pronounced curve with those lenses.

[@glennwilloughby6213]

Place lens on the cloth that comes with the cleaning kit, on a flat surface (usually the bed). You should be able to gently rock the lens if curved side down. Always clean the lens before replacing.

[@cyberlizardcouk]

@@glennwilloughby6213 I would have never thought of that. Thank you.

[@gabrieldillon11]

I just recieved my k40, and lens is curved side down, so it comes from factory that way

[@alkaenterprises-]

Some lenses have convex and concave surfaces and not a flat surface. I guess concave surface should be facing the material to be cut.

[@SmokeMirrorsVideos]

Generally yes.

[@catvw]

Please take away the stupid musak so that we can understand what you are saying more clearly