1.6 material or Poly ??

[majucalicut]

Dear Friends,

I would like to know which is better in terms of impact resistance. For rimless frame, what should I suggest, poly or 1.6 material. I heard that 1.6 materials are impact resistant material suitable for rimless. Kindly advice

Regards
Maju

[eyes4u]

I have been using trivex or 1.67 over poly lately...I find alot of the poly materials split and crack at drill points and on semi rimless where the nylon line starts and a metal frame begins the poly wil chip or split internally. I like the thinness of the 1.67 material and thats its aspheric

[mshimp]

I have heard of a new 1.60 material that has many of the same properties that trivex has. You may want to check that out. Otherwise if the RX is -3.00 or less I would use trivex.

[PhillyEyes]

TRIVEX, TRIVEX, TRIVEX, TRIVEX

[eyes4u]

I have used a 1.60 in the past,are you referring to something new and is it thinner and lighter than trivex?

[TLG]

I have heard of a new 1.60 material that has many of the same properties that trivex has. You may want to check that out. Otherwise if the RX is -3.00 or less I would use trivex.

From another thread authored by DragonLensmanWV -> http://www.ppgtribrid.com/

[Nikolay Angelov]

There are different plastics with 1.6 refractive index (acrylic, MR6, MR8).
The most common (and best at the moment) is the MR8.

It is our preferred rimless material, it is strong (higher tensile strength than Trivex) and rigid (central thickness: 1mm).
It is very hard to brake, BUT if it does it shatters into pieces.

On the other hand, Trivex is more like rubber (or chewing gum). It does not brake as much as flexes etc. Here is a nice example:

(also Trivex tolerates well poorly done drilling and assembly)
We use Trivex instead of MR8 when the client is of a "careless" disposition and the RX is small positive one (thin edges). Trivex bends and does not shater when the thin edges of the mount are abused.

On polycarbonate: We left this clunker in the previous century.
We can get the same poor optics with 1,74 and 1,67 if we are so inclined.
I actually can't comprehend why it is still in use at some places?!

[chip anderson]

You'd be amazed how many people on OB think Poly is the only matherial to use. The other day I was in the waiting room of an OMD which ajoined his in office dispensary overhearing that Poly was "Our most durable material."

Chip

[cocoisland58]

I actually can't comprehend why it is still in use at some places?!

The assumed safety properties is the reason. Kids, sports glasses, etc. Industrial safety accounts require it be used.

[Snitgirl]

Trivex
Phoenix

[WFruit]

And cost. Trivex is still usually more expensive.

[Chris Ryser]

No Poly crazing or cracking when doing a proper job................................

I have been using trivex or 1.67 over poly lately...I find alot of the poly materials split and crack at drill points and on semi rimless where the nylon line starts and a metal frame begins the poly wil chip or split internally. I like the thinness of the 1.67 material and thats its aspheric

There are ways to get around it. No Poly crazing or cracking when doing a proper job................................

http://www.vision-ease.com/Portals/V...lessMounts.pdf



http://optochemicals.com/products/info_drillseal.htm

[Nikolay Angelov]

I didn't know prices were like that.

Here polycarbonate, MR8 and Trivex are about the same price.
We have some quality brand name MR8 lenses that are actually cheaper then the other two.

The Chinese polycarbonate AR lenses are indeed the cheapest here but their quality is unacceptable.
They self-destruct like a "Mission Impossible" prop.

[bigeyejim]

Cool Video!!!

[Chris Ryser]

One other reason why Poly can crack..............................

Mechanical Properties of Multilayer Coatings on Polycarbonates
Prepared by PECVD

V. Buršíková1, L. Zajíčková1, J. Buršík2 and J. Janča1
1Department of Physical Electronics, Faculty of Science, Masaryk University,
Kotlářská 2, 611 37 Brno, Czech Republic, e-mail: vilmab@physics.muni.cz
2Institute of Physics of Materials, Academy of Sciences of the CR, Žižkova 22, 616 62 Brno, Czech Republic

Abstract
In the present work, several different types of intermediate layers between the polycarbonate (PC) substrate
and the plasma deposited hard SiO
x-like protective coatings have been studied and their influence on the
mechanical properties of the whole coating/substrate system has been compared. By the help of an optimized
fracture resistant intermediate multilayer system and the hard SiO
x-like protective coating the original PC
surface hardness (~0.2 GPa) was increased by almost two orders of magnitude (5-9 GPa).

Read whole report: http://134.147.148.178/ispcdocs/ispc...Papers/845.pdf