RDWorks Learning Lab 202 More Laser Cutting Investigations @SarbarMultimedia

Uploaded March 2021 | Updated September 2026, 1 week ago

Despite trawling through many research papers. I have found no explanation as to why and how a laser beam cuts materials. We all know it does so because of the FOCUSSING power of a lens. We have all used a magnifying glass to focus sunlight onto a piece of paper and found that it burns a hole (or fries ants!!!!) BUT it ONLY works at one FOCAL POINT. Drop the paper away by a few mm and the effect is zero. This in itself poses a logical question. When we focus a laser beam onto the SURFACE of the material we get what we expect , a burnt dot, but below that focal point according to all lens theory ( and the magnifying glass proof) the beam is losing its burning power .......how therefore can it cut a parallel kerf many millimeters deep????? The problem has been around for ever and, despite my failure to find research on the subject, I feel sure that I am trying to reinvent the wheel....or am I?
In this session I push through methods of trying to "see" the beam in an effort to find an objective way to asses beam/lens performance in less crude manner than just cutting material..By the end of this session, I honestly believe I have opened a new exciting door to the future.

RDWorks Learning Lab 202 More Laser Cutting Investigations

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$RDWorks Learning Lab 245 Lenses and Laser Beams A Marriage Made in Hell Lenses have worked perfectly for thousands of years BUT laser beams have only been around for about 60 years Yes, its still light waves/rays and will be refracted by lenses in exactly the same manner as always. Normal light is more or less uniform intensity across the surface of a lens whereas the Gaussian profile of a laser beam means it has most of its light INTENSITY at and around the centre of the beam. Light refracts (bends) as it passes through a lens which is designed to direct all light energy to a common point (the focal point). This means the outer edge of a lens must refract the rays more than those at the centre. Our laser machine lenses are manufactured with the age old (and simplest to manufacture) form of lens geometry.....spherical. This shape has imperfect focusing properties called aberration. Thus, light from the outer edge of a lens focuses at different points to that through the center. For uniform light this weakness is hardly noticable, perhaps a bit of blur if you look carefully. However, for a laser beam with its maximum intensity (its max ability to damager material) at the beam axis, this becomes a problem. A lens may have a nominal focal point that would apply to normal light, but pass laser light through it and the maximum intensity at the axis of the beam meets the least refractive axis of the lens. Bad news. Hence the title of this video.......they stay married (with all the imperfections) for the sake of the children and to the outside world all seems well. This video is some background about several months of test work I have conducted using various beam sizes and many lens types to examine the inner workings of this imperfect marriage. Most will not be interested in the large report of my tests and findings because on the surface, laser machines do aproximately what is expected of them without ever needing to lift the hood. If you have an interest in the report I produced then please contact me via this private contact form. https://forms.zohopublic.eu/ndeavorlimited/form/K40XtreeemLaserCutterContactRussSadler/formperma/k2Cn0QN5ChpazfTMAUw25lZ-FKpjZa96TQWHjv3ntOg$

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