Waterjet cut lens

[Mustafa Umut Sarac]

I am thinking and researching lens making technologies for a long time.

I found that casting optical polymer cubes and order a waterjet cut cylindrical lens elements from these blocks , it can be a answer to most basic and most complicated lens element production problem.

Waterjet cutting services are everywhere and they can cut even many inches thick steel.

They jet water higher than sound speed with ceramic particles inside and only you have to do is order smallest particle size powder cut.

Optical grade polymers are everywhere and without need a expertise , you can order a polymer block casting in to a basic rectangular mold.

Than all cutting done in water jet cutter service.

My problem is , if I get a dagor design and cut this design with water and cylindrical not spherical , what would be the image like ? This is silly question but I need still an answer.

There are excellent Soviet and Russian journals online at web and I found an article on LOMO Cinema Anamorphic Lenses design guide there.

Without diving in to design staff , I think I will order a design from India.

Thank you ,

Mustafa Umut Sarac

Istanbul

 

[nick mulder]

Mustafa - can you please show us some things you've actually gone ahead and developed ...

COMMIT

 

[AgX]

Nick,

Mustafa is a mind-tickler and l love his proposals. Most of them. Those I understand.

 

[Mustafa Umut Sarac]

Thank you AgX. 3500 posts and I did not read a lot. Where do you hide them ?

I am remembering your Agfa , Polaroid posts and they were excellent.

Let me search for you. I am sure I will be impressed.

Nick , I sent the idea to Chinese and american lens designers and I am sure Chinese one request 1/100 !

I ordered a Luigi Colani Americas Boat design 3D model and sections from India and 12 hours later , it was at my hand for 100 dollars. There are big things going in East.

Umut

 

[keithwms]

Well, plastic lenses are not unusual (some of us are wearing them right now!) and water cutting PMMA has certainly been done. I think you can tune the index of refraction of the polymer (I am thinking of PMMA) with organic dopants, though I don't know whether the numbers work out anywhere near what is needed for modern lens constructs.

But the big problem, I think, is that plastics are simply not tough enough for routine use. The surfaces are very prone to scratches and, actually, a high-grade chunk of PMMA isn't cheap. I've had quite a few things machined out of it and it was very expensive. And you pay for what you don't use. Add dopants and I don't think there's much money to save, and in the end you're left with a lens that scratches very easily.

 

[Mustafa Umut Sarac]

You can increase the PMMA refraction index to 2.9 with doping with titanium oxide at sol gel but it prone to crack.
Optical polymers are sold with different specification and it is easy to select hard to scratch one from the lists.
My eyeglasses are plastic for the last 25 years , I used 1 dollar one to 300 dollar one but I did not scratch it in every environment.
And my idea is cold cast as much as you need , not buying big piece and throw the remaining.
If you shot a bullet on to the front element , you can cast and cut it again. Not like glass.
Organic dopants color the polymer if I am not wrong. There are many organic fluids for lens use and they are dark red.
Problem , is there a all cylinderical camera lens without use a spherical ?

 

[Q.G.]

What do you hope to achieve?
A cylindrical lens does not form a complete image. It, obviously, only works in one direction.
Can be used as a modifier (such as an anamorphot) in another optical system. But on its own it's of no use.

Its easier to cast a polymer in the desired shape than to make a square block of it you have to cut and polish to the desired shape.
So why waterjet cutting?

 

[lxdude]

I have experience with waterjet. It's not really precise. For example I have waterjet cut 1.5 mm thick aluminum and even at that thickness the sides have a taper. It would be OK for roughing, but so would other methods. You will still have to grind and polish the usual way.

 

[Mustafa Umut Sarac]

Q.C. ,

There are few ways to produce optical polymer lenses. First , is to use a rp machine and manufacture your lens out of it. It will have layers and these layers will make steps on the lens. Than the lapping guy laps the lens and produce your plastic lens. Than you have to ask help from silicon mold guy and bubble free molding is expensive and it is made from silicon. Silicon have a soft nature and it is very easy to damage it when you are taking out the lens.I called them and ask a canon eos body shell production , cost 600 dollars. Precision rp and mold is very expensive.
Most importantly , you stuck in to one lens because you wasted great money to it.
Cold casting and water jet cutting is cheap and you can change the design every time.
Lets talk about lens design.
May be I can use a lens system includes vertical and horizontal cylinderical lens elements together.
And optical system cover a ready bought spherical elements. There are tones of cinema lenses done with this mix.

lxdude ,
Yes , Lapping is a technique to correct plastic lenses also.

 

[Q.G.]

Mustafa,

Before you can 'waterjet' a block of polymer, it too has to be cast.

A mold (why silicon? How about metal?) can only be used for one design, yes.
But what working lens are you hoping to get using a waterjet to cut a block of polymer to shape...?

 

[Grif]

They do a similar process in mulit axis machining centers. The plastic stock would be on an arbor (chuck), spining, and while spining, with the waterjet running the plastic is moved into and out of the waterjet, while rotating (yaw) to move the cut from the outside to the middle of the lens element. (boy, do I suck at trying to explain this.)

imagine a wood dowel in an electric drill, with some sandpaper glued to the wall. walk up to the wall with the drill running, push the end of the dowell into the sandpapered wall, and just twist the drill from side to side to "wipe" the end of the dowell against the wall resulting in a rounded end.

Now imagine doing the same thing against a single knife edge, you can still get a rounded,,, or asymetrical end on the dowel just by moving the drill around by twisting it, and moving it in and out. Now change the knife edge to a water jet, just using it as an abrasive surface to work against.

I just have to believe they have multi axis water jet units with live work holders.

 

[Mustafa Umut Sarac]

Grif ,

Yes , there is a higher end , glass shapers ,ceramic doped magnetic liquid rotate and lens shaped with it.
This is a RIT research , answering the need of stadium big lasers lens making problem.

I dont know they move the lens or they move the waterjet at cnc shop but I think my way - as sinatra sings - not requires 5 , 6 axis expensive machines. They will cut 2D shapes and lap and I will use in the group ready sold aspheric or spheric lens.Only I need a Indian or Chinese designer.
QC , Yes , block must me casted and it will be done with cold casting . It is widely available. I worked in mold making business and smallest mold costs 2500 dollar and it doesnt stop there , you must find special steels , correct modeller , programmer , new cnc machines without lost its calibration , lots of plastic pellets , an powerful injection machine where its owner agree to manufacture your part. And optical plastic coming of injection mold requires flame polishing as steel mold requires also.
Not a amateur way. And extreme temperature control.