Is it possible to produce 3D printed optical lenses with a 3D printed lens grinding machine? 

Good idea!

Real photoresist used in silicon fabs is very viscous. Probably moreso than resin. You just have to spin it faster/longer

Spin coat machine. I work for a manufacturer in one of their labs

Thank you very much for the nice comment ;-)

I was just thinking this last week!

Haha v funny.. there's so much more to the optics than just the shape. Not the least are the coatings

@@acasccseea4434 You know that lenses were being used for photography for quite a while before coatings, right?

​@acasccseea4434 Coatings do nothing but protect the out element and decrease internal reflections. The magic happens in the glass itself and the shape of the glass.

The next project will take some time, but I already have a rough idea of it.

Just saw this in a mosfet video then came here beautiful work @FraensEngineering this opens up a lot of possibilities love it

Your basically a keystone engineer for diy development

Thank you very much ☺️

Hi, for more details you can check out my website. I have discussed some points in more detail here: fraensengineering.com/how-to-create-3d-printed-optical-lenses-with-a-3d-printed-lens-grinding-machine/

Many thanks for the tip and the nice comment.

Those mirrors have the metal on the front surface, and there's videos on using microwave parts to turn a metal sheet in to a plasma to coat the surfaces of 3D printed parts.....

Mirrors are not made the same way lenses are.

Thank you so much for your kind comment!

@@FraensEngineering ur welcome 😁

😂 Yes, you're right. 73k is not bad for a channel of my size though I think. RU-vid takes time. RU-vid rates it very highly when people watch videos for a very long time. But since I don't speak in my videos, the playback time is also a bit shorter.

That's a good idea. Above all, the lens would then be much more homogeneous than 3d printed.

"Runout" means the vertical axis on which the lens is mounted for polishing is wobbling about: en.wikipedia.org/wiki/Run-out

That's a great idea. Do you have a link where I can look at this type of machine?

@@FraensEngineering Unfortunately I don't. I've seen 3d printers with an added 4th axis but support for them is not extensive because it's such a niche build. Perhaps just a 3 axis machine with a special flexible head surface that can flex and be normal to the surface on a ball pivot with a spinning sander would be sufficient for complex lens geometry?

Oh trust me it is, just like the rest of Europe. We're lagging so behind in the R&D (except ASML).

Hi, I'm not going to make any lenses at the moment. I'm currently developing another project. A fully 3D printed telescope would be a nice project. I will add this to my collection of ideas.

I like the idea. I will try it out to see if it works. I have some old CDs lying around in the cellar. What product or cloth should I use to do this?

Excited 8) im not sure, the local "gamestop" here has a machine that i think removes a little layer to get rid off scratches, so i dont know if its a sand then polish process. Also the lens project is really cool and has lots of use cases ❤

You're absolutely right. Ball bearings are certainly not the best solution. However, the forces are very low. But bushings (sintered bronze or IGUS plastic bushings) would be much more backlash-free.

Unfortunately, I have no long-term experience of this myself. I have only had my resin printer for a short time. I keep the lenses in a dark box. At the moment they are still transparent.

Sad but true. This is the bureaucracy....

I don't quite understand what you mean.

Hello, as far as I know, aspherical lenses are ground using CNC. I don't think it will work with this.

Good question! I would say grinding block pivot bearing linkage ;-)

Hi, sandpaper is certainly not the best way to polish lenses. However, I was amazed at how well it worked. I wanted to use pitch at first. However, I had the problem of buying pitch in a small quantity. So I thought I would use modeling clay. This is certainly not ideal either. I think that with the right procedure, a lot more could be achieved here. It would be great to try using a lens blank made of acrylic glass. Or to cast a lens with the resin and then polish it.

The curvature is highly dependent on the polishing shape. Unfortunately, I did not have the opportunity to measure the lenses. Some experiments would certainly have to be carried out here.

Sounds complicated ;-)

@@FraensEngineering sure is! Plus the smells... don't do it in the kitchen

You're not wrong. The bracket is not completely concentric. I used an aluminum shaft. My first attempts to clamp the bracket directly to the shaft with a worm screw wore it down considerably. Furthermore, the aluminum shaft does not have an H-fit. And the cheap metal flanges are not the best either. These also have some clearance to the shaft. As a result, the worm screw presses the bracket slightly to the side. These are all points that could be significantly improved with the right material, proper ball bearings and precisely fitting flanges. But it's not so bad as it is ;-)

@@FraensEngineering Photographers and scientists making custom garage optics would be badass! Reliable lenses that could be treated like disposable/consumable gear would be fun to see

That's right. However, they will not be satisfied with printed lenses.

I'm not sure if 3D printed lenses meet your requirements.

Sub inch focal length is extremely difficult. That would mean 40dpt or more. Even in an industrial setting that's extremely difficult,, let alone DIY. And you also need the lens with a extremely high quality to get that narrow focal point, so you need aspherical lenses that can not be produced in this process. Can you use mirrors to lengthen the focal length?

The basic principle of lens grinding is relatively simple. It's all about the undefined movement. take a look at how lenses are made in India ;-)

I think I need polishing pitch for glass. Plastic blanks would be interesting. I have already thought about a microscope. But that is not easy. You would have to have really perfect lenses for that

@@FraensEngineering i would recommend huygens optics and breaking taps' lens videos. they are really informational and can get you pretty close to your microscope or telescope. also i dont think i have ever seen a fully 3d printed telescope on youtube before, so it will definitely be a big thing. best of luck!

That would be really interesting. Maybe you could coat the parts somehow?

For a telescope you would want to use this machine for grinding but as a material for lenses or mirrors you would be much better with glass. It's stable, opticaly clear and homogeneous and much easier to actually grind. As for mirror coating it's probably a some sort of PVD (physical vapor deposition), usually aluminum is used nowadays. You can chemically coat with silver but it tarnishes so quickly it would not be very useful

A laser lens is rather not possible. However, the idea of printing just one lens mold and then casting it with resin has already been considered. I think this would improve the quality considerably.

Polishing pitch is required for glass. But you could try it with acrylic glass.

It could work with a small polishing mold. In any case, the eccentricity can be set so small.

That's a good question. I take what I have ;-)

Grinding flat mirrors requires a different type of machine as far as I know. I'm not sure if this is possible with this machine.

@@FraensEngineering it needs to be a concave mirror.

I think it could work with the right sanding block. What material would the mirror be made of?

@@FraensEngineering aluminum, I plan to cnc the rough concave shape prior to sanding.

If you have access to a CNC, you could perhaps also use it to make the grinding mold. Or it would be better to use polishing pitch. You can buy something like this here: pieplow-brandt.de/

You could already try to print the form. When making lenses from glass, polishing pitch is used instead of clay.

I don't have an idea yet. But I'm sure I'll need a lens for some kind of project.

@@FraensEngineering haha you are so awesome for creating such a complex assy just for the sake of making lens !

I'm not sure. Telescope mirrors are normally polished with other machines. But I have already thought about whether this would be possible.

@@FraensEngineeringSeems like you could print the hyperbola directly in resin then polish it out the same way you would with glass. I think the only concern would be would the resin be able to handle the aluminum coating

Ideal would be a spheroid with optical sensors all around- and magnetic fields induction- allowing for attraction of ferromagnetic liquid with refleciton properties. Then set AI loose on the input (em-fields control) with a defined visual input, and correlated against the output. Basically shape the optical setup to the ocassion.

@@Canonfudder That was an awful lot of words to string together and not actually say anything...

@@eclipse2966 ? Why? It makes perfect sense to me. Instead of doing the thousandthst expensive synthetic copy of the human eye, lenses and everything, make instead a cheap eye from some electro-magnets and reflective ferrorfluids, that can physically shape itself to whatever situation it find itself in. Its night? Shape it to something tubular like an owl has. And if you use AI and ground-truth data, you can automate that process..

It sounds interesting what you are doing. I think they certainly have better opportunities at a university than I do at home in the basement.

My insight as far as varnishing is concerned is that it doesn't make much sense with cleanly ground and polished lenses. In principle, however, varnishing can achieve a surface that is more attractive to the eye

@@FraensEngineering aah right that makes a lot of sense. The lenses already looked very shiny in the video, but it's probably a bit hard to tell on camera :)

Good idea. I'll have a look around.

I have watched a few videos about this. Very interesting machines. But I haven't looked into it in depth yet. Maybe I'll take a closer look at it in the future.

be aware that this is a deep rabbit hole@@FraensEngineering

Many thanks for the tip about the book. Unfortunately, I am not an optician but a mechanical engineer. I think that with the right knowledge I could still get a lot out of it.

one day I have become very interested in telescopes so researched a lot about making mirrors for them. Basically the same machine is used in the process. Several things stood out to me in this video. Your grinding tool should be grinded a little bit as well during the process, that way eventually both surfaces take spherical form. Grinding resin is more complicated than grinding glass, so it's trial and error but don't use sandpaper, I would try making tools maybe from epoxy mixed with grit (you can buy grit separately but also... burn some sandpaper for testing?). Clear coat is also a bad idea. For resins I have found that automotive polishing compounds work the best (I use 3M fast cut extreme and 3m Ultrafine). Sometimes you can ask auto paint workshop to buy just a small quantity (or exchange for a chocolate bar?;), you really don't need much, a syringe worth of compound will go a long way. I have used like a 1 gram of each compound polishing 50 epoxy resin pens last month.

Hello, thank you for sharing your experience. I think there are already a good number of ideas and improvements.

The largest one I polished was 100mm. But I think you could certainly go even bigger. It would be good if you could then print a larger lens holder.

I can well imagine that. I have not checked with a microscope. An experiment with acrylic glass would be interesting. What do you think?

@@FraensEngineering depending on uv resin you've used, acrylic may be even easier to gring and polish, so why not :)

I do not hide them on purpose. It's a bit difficult to film transparent objects.

I think that could be difficult because glasses are not round. Maybe Harry Potter glasses ;-)

I was wondering if you could DIY your own prescription glasses and bypass the expensive glasses industry. Frames are usually so expensive, more than the lenses! We could surely 3D the frames. Now you've shown its possible to custom make lenses.@@FraensEngineering

I think the quality of the lenses should be much higher for spectacles. But you could grind lenses from acrylic glass. Some ideas have already been put forward here to increase the quality.

I think the quality of the lenses should be much higher for spectacles. But you could grind lenses from acrylic glass. Some ideas have already been put forward here to increase the quality.

@@kennethmui88 He´s from Germany... He gets, like any other, his glasses for free...

600mm is not possible with this machine. The machine would have to be built much larger. The sanding head should then be at least 300-350mm. This also raises the question of how to manufacture such a large grinding head. I think the machine would have to be built very sturdily to avoid vibrations.

@@FraensEngineering I have a 330x330 printer, could I do multiple parts and then sand the head smooth

That would have to be tested.

I've been waiting a long time for someone to test it ;-)

Exactly. The lens was glued on. The adhesive is easy to remove.

But then the lenses should be made of acrylic. 3D printed lenses have problems becoming accurate due to the layer structure.

I don't quite understand what you mean. Which phone do you mean?

@@FraensEngineering jerryrigerverything used similar but expesive factory made machine to polish away scratches on phones.

Yes, the lens became a bit flat ;-)

I mean there are shops online selling eyeglasses for $5 a pair, inclusive of the frames. Sometimes, when they are on sale, you can get2 for $7. These are 2 glass lenses + frames. Perhaps you could get the uncut optical blanks? These are quite large, and you don't even need the frames.

Alternative, print the mould instead of the lens. Pour the resin in, and cure them all in one go. And you have no internal layer lines! The simplest would produce plano convex lenses, but perhaps that would work.

Hi, all very good ideas. I wanted to explore what is possible with this project. I couldn't see any internal structures by eye. The material seems to be relatively homogeneous. I think this is because the UV light shines through the transparent resin and exposes the layers above it again. Lenses of better quality can certainly be produced with a mold. With the machine it would also be possible to polish raw lenses for your own needs. All in all, the project was a success for me. Someone had to test how far you can go ;-)

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