[SGVHAK] 3-D print a magnifying glass?

[Claude Felizardo]

What is your application for wanting to print a magnifying lens?  Is there
some special shape that you need like large notches cut out in the sides
for mounting?  Do you want it for reading or for controlling illumination?
 Do you need to combine it with a prism? That might be handy.

What's the typical melting point for extrusion on a 3d printer?  100-200C?
 You might be able to melt polycarbonate at home but I don't think you'd
get a consistent print especially as you move around the build table.
 Glass requires something like 1000C?  Plus I don't see a way to cool it
gradually to prevent breakage.

Then there's the shape.  I think a magnifying lens has to be concave, if
it's flat on once side then you've cut the power in half no?  A fresnel
lens cuts down on the volume of material needed and space but I don't think
you really want to try reading through one for any length of time.

At this time, I can not imagine a hobbyist grade 3d printer capable of
printing a magnifying glass of any decent quality for reading.  Even
assuming it would set consistently throughout the printed material much
less where it touches material deposited by a  previous pass the amount of
refraction would be so inconsistent it would be useless.   The resolution
of 3d printers are in the order of fractional mm but I think you might need
something finer?  I would think there would be so much optical distortion I
can't see it being useful for reading.

Then there's the polishing that has to be done, again, I think it would be
easier to just purchase a blank and shape and polish it down.

Finally there's the coatings on the lens.  You want to protect it from
scratches, etc. I just don't see all that fitting on a kitchen table.

Claude

Okay, looking around...

http://www.inkpal.com/ink-news/3d-printing-glass-solar-3d-printer-hp/
produces hand blown glass quality.

http://www.designnews.com/author.asp?section_id=1392&doc_id=267310&cid=nl.dn14&dfpPParams=ind_183,bid_27,aid_267310&dfpLayout=blog&dfpPParams=ind_183,bid_27,aid_267310&dfpLayout=blog
not sure if this link will work.
Try searching for "3D-printed eyeglasses are fit for a king".

Oh, here's a press release:
http://www.uef.fi/en/-/3d-tulostus-mullistaa-fotoniikan-maailmaa

Says it will be available soon but perhaps at prices only a king could
afford?







On Tue, Nov 19, 2013 at 7:41 AM, John Kreznar <jek at ininx.com> wrote:

> In a posting purporting to be from Matthew Campbell <dvdmatt at gmail.com>
> but lacking a digital signature, it is written:
>
> > Impossible as you used the "Q" word. (Quality).  I have used plastic
> > glasses and some expensive ones are OK but you need a very optically
> > consistent material and you can't get that from a printer.
>
> Exactly what I feared.
>
> > Prove me wrong ;)
>
> Please, someone?
>
> --
> OpenPGP key: http://ininx.com
>  John E. Kreznar jek at ininx.com 9F1148454619A5F08550 705961A47CC541AFEF13
>
>
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