How to Select the Proper Lens for Your CO2 Laser and Understanding Laser Optics
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- เผยแพร่เมื่อ 7 พ.ย. 2017
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I briefly describe the laser optics used for CO2 lasers and the lens focal specifications and concepts to consider with the laser energy convergence after the lens.
Another helpful video on finding the focal length of your existing lens:
• blackTooth Laser Cutte... - วิทยาศาสตร์และเทคโนโลยี
Thank you! Very comprehensive and now i understand the difference!
Great explanation, just one thing to add: the main reason you'd use a lens with a larger focal length is to achieve more square cuts with thicker material. Based on my experience, a 4" lens doesn't increase the cutting power compared to a 2" one.
Great explanation, thank you very much
Thank you so much, I've had my co2 for about 2 years and the mirrors / lens just burnt and need replacing and I was clueless with all the different types and focal length options. This was a great eye opener and gave me the info I needed! Thanks again!
You should do one that talks more in depth about increased optical aberration with the longer lenses. I mean you did sorta cover it, I'd just like see a little more in-depth discussion. The home built laser crowd has exponentially grown over the last few years due to opensource builds like the old lasersaur community. Now that parts and available data bases are more easily accessible, I've found the information base has been breached once again from there being a real lack of it. I recently started doing my part by opening up a facebook group "Laser Builders Guild" in response to seeing youtube channels like Furtherfabrication has made. There are a lot of various people that cover different areas of things related, but I've yet to see anyone that has a solid base of info on more than a couple things. It would be nice to see a more compiled weekly information dump in a cataloged structure based around your style, which I appreciate. You get to the point and have a well produced method of doing things that illustrates things fairly seamlessly. If you need topics recommended I can keep you busy!
Thank you. This definitely helped me understand this concept much better.
Excellent. Also, make sure to take a gander at the comments. There are some with good information.
Great explanation thank you!
Really good explanation, thanks
thank you for this video. it's very usful!
Helpfull video... thanks buddy !
Hi Patrick,
thank you very much very informative video subscribed
I want to replace the lens on my 80w chinese laser, I do a lot of engraving and cutting birch and wood.
Machine bed is quite large at 1300x800 so I'd like a lens that can cut and engrave reasonably well across all the surface.
I don't know if I should get two lenses one for cutting one for engraving or preferably one for multi purpose, can you please advise on what lens I should get and better yet, where to get a good quality lens kit ?
Thank you
I've read about high resolution laser heads. It says it has 2- 2" or maybe 2- 1.500 lenses. Are they stacked. Are they Plano or meniscus lenses. And also. If just using one lense. Which is better for finer photo engraving details plano or meniscus? I'm wanting to make another head for my laser and want it HR but have no idea how it's set up. Thanks for your time
Thankyou . I'm just learning and this is great info 😀
I was told not to a decade back in other videos.
@@PatrickHoodDaniel not to ? Not to learn or not to teach ? You seem to have acquired both skills as the video was extremely relatable and well explained . And I know as my mother was a teacher and my father an engineer .
Kudos to you 👍👍👍
@@MrKrueger88 I was told not to. The explanation was that the stands loose their elasticity. The comment was on my pick and place machine assembly videos.
@@MrKrueger88 I think this comment got misplaced when I was making bulk replies. Haha. My apologies..
@@MrKrueger88 I wonder how many other comments I messed up. 🙃
Can you share more on spot size? Does the target material and the processes like engraving, abrasion, fading, and marking effect the laser and mirror selection?
I got it regarding focal length why can't I find out about quality why I can buy a 14 dollar or 24 dollar or 59 dollar lens and do on. Whstvsbout quality of lense. Please help me with this
thank you, I love you!
Thank you for this video. I always wondered what the different diameters on Focal Lenses for Laser Heads were for. I was under the impression that the diameter dimensions must have had something to do with what I was calling the "sweet-spot" of the focal point of a lens. I also was not aware that one diameter of focal lens was preferable for cutting and another one for engraving. I always thought that just knowing where this sweet spot was on your laser machine then by controlling the Z-axis platform then you can get your material as close as possible to the sweet spot and be able to do both cutting and engraving.
Thanks for the tutorial on the angle exercise to find a good range on a laser machine with a 4" focal lens too.
Is it preferable to work with two focal lenses and swap them out between cuts and engravings? Thank you again.
Yes, each focal length will have its application. For instance, if you are engraving, a shorter focal length will be better for most materials since you may not want to remove material too deep. Longer focal length lenses can also be used for materials that may not be perfectly flat, or for materials like anodized aluminum where it is harder to get to that sweet spot of the focal length.
May I ask what software you are drawing in during the video?
I use a program called Leonardo: www.getleonardo.com
It works with pen based computers like the Surface.
Hi.
Isn't it possible for the 4'' focal length lens to incline more the plan you're hitting, so you get a wider burn (as wide as the 2'' ) so you get a good accuracy ?
Hi Harold. What do you mean by "incline more the plan"?
At 5:12, you seem of using an inclined plan to detect the focal point position by moving the laser from right to left and looking for the smallest burnt spot.
I mean, if you give more inclination to the plan, you'll get bigger change in the spot size, and in some way, more "accuracy" even with a 4'' focal length lens.
But I might be out topic ....
Ah, inclined plane. Sorry about that. Yes, it will create a slightly larger kerf, but the kerf will still be the smallest at the focal point on an inclined plane. This is just to determine where the focus is located and to establish a measurement to be used when normal (not inclined) work is done.
Yes, inclined plane. Sorry for my English !
So, would it make sense to give it more inclination to get better accuracy with the 4'' focal length lens at 5:41 ?
Or a longer incline. Either way is fine.
It is called rayleighlenght and is commonly known
I imply no criticism of this video because it is just passing on well tested conventional knowledge.
This is exactly what Galileo. Copernicus and Kepler would have drawn more than 700 years ago. Basic lens theory may have been compuerized now but the principles have not changed and , as described in this video, these principles govern all modern lens designs that we use for our laser machines. As recently as the 1960s man discovered how to make a special type of light that Galileo etc could never have imagined. LASER light. Yes, this is still light and the rules of refraction that govern lens design are still obeyed by laser light but, with consequences that the ancients could not have forseen. This video illustrates how NORMAL light reacts after passing through a lens because the everyday light we live in is basically uniform intensity and we use lenses for IMAGE transmission as in cameras, telecopes and projectors for example. The purpose of LASER light is to damage materials by intense concentration of light energy. The type of laser beam we use is NOT uniformly intense. The beam has a VERY high intensity core that gradually feathers to zero intensity at its outer diameter. Add to this an annoying property of the sperical geomerty lenses we have to use called sperical aberration (see users.ntua.gr/eglytsis/OptEng/Aberrations_p.pdf dont worry about the maths just study the images). You will soon see that there is no such thing as a fixed focal point and that concepts such as depth of focus are meaningless because the lens is not focusing uniform intensity light to a nice theoretical single focal point, no, instead the lens is being required to focus a whole range of DIFFERNT intensity rays of light to various focal points above and below the optical focus.. There will be an INTENSITY focus where the combined intensities are optimal Although this point will be fairly small (mayybe 4 or 5 times bigger than the theoretical optical spot size) some of the most intense rays will pass though the axis of the lens and experience almost zero refraction. This will cause thes most damaging rays to focus way beyond even the net intensity focal point. As I mentioned earlier, Galileo could never have envisioned this mess and what happens below the INTENSITY focal point has no resemblence to the diverging energy density pictured in the video. Can I prove this? Just watch this 30 second video and ask yourself how the "facts" in this video can descibe what you see here th-cam.com/video/vTEAm-01E1Q/w-d-xo.html
We cannot design lenses differently but we should understand that the way that laser beams and lenses interact is not the same as light passing through a telescope. Yes we can get away with adopting the telescope theory because it works 90%. We don't really worry about the inconsistencies, we just "work with it"
Thanks for the information; however, you should add this information on your video that you linked. That would provide a more effective delivery of you explanation. Also explain what setup you have. I have never gotten a 90 degree cut. It always follows the slant of the focus Can you provide further information why that happens?
@@PatrickHoodDaniel
Thanks for your understanding.
I saw your video as an attractor of new users looking to understand how to use lenses. I already have this information available on my own videos but it's far too technical and boring for newbies and I care not for traffic nubers as I don't monetize my content. I do what I do for personal pleasure and to exercise my two remaining grey cells with laser subjects that are misunderstood or not understood at all. It was about 4 years ago whilst doing cutting tests with a few different lens types that I observed how they did not perform to specification or in a manner predicted by experts.
I already understood why different materials cut at different speeds with the same parameters and lens, but these illogical observations set me on a long journey of trying to understand the mechanism by which lenses can channel light energy to cut a deep parallel kerf as I demonstrate in that short video. Doing deep cuts was one discovery but understanding how it's done was a more challenging task which did not decode until last year. I have several videos that try to explain the mechanism and I then thought I understodd everything about how lenses work. I was wrong becuse in subsdequent experiments to exploit the high intensity of a very small diameter CO2 beam to create super cutting capability from a low power (30 watt) source, I discovered that single lenses of any focal length were incapable of focusing the small beam diameter. That was a major surprise for me and after extensive testing with many lenses I was able to finally understand how the diameter of a laser beam and its intensity distribution create different but repeatable outcomes for each lens geometry. However, change the beam diameter or the intensity distribution within the beam and the outcomes will be different. It is a truly strange relationship that laser beams and lenses enjoy and I am just about to explore how cutting with less power (a different intensity distribution) withi a glass tube beam, may create more efficient cutting. That idea is counter to all my beliefs about cutting but I must explore it because my data hints that there could be benefits.. This is a very complex subject that I feel sure has never been investigated before.
If you need specific videos to watch then please use the following private contact for and I will help track them down.
Best wishes
Russ
forms.zohopublic.eu/ndeavorlimited/form/K40XtreeemLaserCutterContactRussSadler/formperma/k2Cn0QN5ChpazfTMAUw25lZ-FKpjZa96TQWHjv3ntOg.
@@SarbarMultimedia Much appreciated Russ. When I am able to wrap my head around the subject, I will make a new video. My challenge is to suscently convey the information to layfolk, so it may take a very long time for the information to be soaked up by my last two brain cells (I am pushing retirement age).
On a side note, you may have the same spacebar hiccup that I have!
Definitely more than 4mm
4mm? Are you referring to the focal length? If so, it's 4 inches.