OL 18 Flashcards
outline optyl
Optyl is an epoxy resin
Manufactured by injection moulding and then dyed and lacquered
Frames manufactured now possess metal reinforcement rods.
Lightweight and hypoallergenic
“elastic memory”. Adjustment temperature at 80 – 100o C, once cooled the shape is retained in “memory”. If reheated the frame will return to its original manufactured shape
outline nylon
material?
manufacturer
manufacture process
lighter than
surface finish/ colour
temp max
strength
with skin?
exclusive to silhouette
super polyamide
manufactured by injection moulding, dyed/ painted , surface gloss applied by lacquering
lighter than cellulose materials and very strong
opaque and provides solid colours, but holds translucent colours well
surface finish poor-spray coloured and baked
newer nylon frames transparent in colour
material shrinks under intense heat of 110
high resistance to breakage but poor adjustment
brittles with age
hypoallergenic- dermatologically inert
tortoiseshell
protected species
can’t be killed anymore
adjustment carried out under humid heat
material bonds to itself under heat and pressure
two or more plates built up into thicker sheet
perspex
PMMA
SUPRA frames made from this
requires strong heat
very brittle
sides not reinforced
polycarbonate
safety eyewear in form of one piece eye protectors and side shields
very soft with high impact resistance
Monel
nickel alloy as base with more precious metal plated
63-70% pure nickel with F, Mn, Cu
corrosion resistant
eyewires difficult to shape so used for temple bridges and fronts
Rolled gold
manufactured as?
colour?
base metal
thickness
manufactured as a combination of base metal or alloy core with an outer shell of surface carat gold
Strong and flexible
Attractive surface colour and finish which is resistant to corrosion
12 or 14 ct gold used most commonly for finish
Base metal is usually bronze, nickel or Monel
Gold skin commonly 1/50 mm thick
gold plating?
manufactured?
cost?
frame material?
base metal?
welding process?
A very thin layer of gold is elctrolytically deposited on the surface of a base metal
Cheaper to manufacture than rolled gold
Frame material is often coated with a protective outer layer
Base metal (usually Monel/nickel and copper alloy)
Following welding process the frame receives six layers of galvanic plating and coatings
• Nickel
• 0.08 microns of 24 ct gold
• 1-2 microns of palladium/nickel • 0.08 microns of 24 ct gold
• 0.5 microns of 22 ct gold
• Varnish/lacquer
describe pure titanium
weight resists strength skin flexibilty
40-48% lighter than conventional frames
Resistant to corrosion and perspiration Abrasion resistance (3x >rolled gold, 10x >gold plate)
Very strong
Hypoallergenic
Flexible (20% >nickel silver)
Clad titanium
manufacture process
material
identical to
pure titanium (Ti) laid over another metal, i.e. the frame has an inner core which isn’t titanium
Nickel-chromium (NiCr) is the metal most commonly used
Overlaying process is identical to rolled gold
Partial titanium
some parts of the frame manufactured from pure or clad titanium, remaining parts from other metals
b titanium is alloy of?
b titanium is an alloy of titanium, vanadium, aluminium and manganese (75-80% is titanium)
For titanium ———-costs are high due to specialised methods for ——–, ——– and machining which must be carried out in an atmosphere containing no ——– or ———-.
- ——– of the metal must be by —– ——— as standard ——— results in ———-
- A specialised ——— method is used whereby all the ——— is removed from the pure titanium and ———– takes place spontaneously
production welding buffing oxygen nitrogen plating ion plating plating peeling plating oxidation plating
two crystalline structures of memory metals
martensite and austenite
specs made out of memory metals are in what phase
martensite
