Ophthalmic Frames Flashcards
What are the most common frame materials today?
- Cellulose Acetate (Zyl)
- Metal
- Optyl
- Nylon
- Propionate
What is Cellulose Acetate (Zyl)?
Most common plastic made by mixing cotton seed fibers with plasticizers and stabilizers
What are the 2 forms of Cellulose Acetate (Zyl)
- Block acetate
- Acetate Granules
Describe Block Acetate?
a form of Cellulose Acetate (zyl) that is a sheet of extruded material from which the frame fronts are milled or cut.
What is the process of making Block Acetate called?
Pantographing
Describe Acetate Granules?
a form of Cellulose Acetate (zyl) that are small pellets of material which are liquified and injection molded.
What are the advantages/disadvantages of Block Acetate?
Lots of waste plastic but result is good strength and stability.
What are the advantages disadvantages of Acetate Granules?
More cost effective way of manufacturing. But some shifting and deformities can occur with temp changes. Metal is usually added into the frame to hold shape.
What are the advantages of Cellulose Acetate (Zyl)?
- Variety of color/texture
- Temple adjustments are easy
- Material is workable
- Frame has some give to it to adjust for lens sizing
What are the disadvantages of Cellulose Acetate (Zyl)?
- Gets brittle over time and may turn whitish
- Colors lost
- Slight shifting so you cannot produce them thin
- overheating can result in pitting
- Heavier than other plastics
- Overheating loosens hinges and hardware
What is Propionate?
new generation of material with properties of strength and shape retention lending itself to injection mold fabrication.
What are the advantages of Propionate?
- Greater stability and shape retention
- lighter weight then acetate
- Overcoats are applied making them more scratch resistant
- Sturdy ultra thin design
What are the disadvantages of Propionate?
- Difficult to dye so colors may fade
- Needs more plasticizers and so gets more brittle with age
- Solvents ruin finish of the frame(including Alcohol)
- Low tolerance to heat, bubbling can occur
What is Nylon material?
A thermoplastic used in eyeglass fabrication that is durable and highly resistant to breakage.
What are the advantages of Nylon?
- Hypoallergenic
- Comfort from light weight
- Chemically resistant
- impervious to heat
- Good for kids and sports
- very durable and resistant to breakage
What are the disadvantages of Nylon?
- Very stiff and difficult to adjust
- Color selection is usually dark solid colors, crystalline colors are not possible.
- Dries out and gets brittle over time
- unforgiving to lenses not sized exactly
What is Carbon Fiber?
a new breed of injection molded plastic frames, lightweight and strong. Black in color, requiring other colors to be baked on.
What are the main visible attributes of Carbon fiber frames?
- delivers the look of an ultrathin plastic frame while holding many characteristics of a metal frame.
- typically carbon front and metal temples
- Black in color, requiring other colors to be baked on.
What are the advantages of Carbon Fiber?
- Comfort
- Baked on enamel finish maintains shine and durability
- Carbon is relatively impervious to Heat
- Adjustable, but hard to damage
- One piece designs deliver a metal look without screws going loose.
What are the disadvantages of Carbon Fiber?
- Front of frame is difficult to adjust
- Color selection is limited to dark
- Sensitive to a variety of solvents
- Lens cut outs can be an issue as there are not screws on a lot of them.
What is Polycarbonate Frame material?
plastic material originally created as a safety material. Extremely durable, filters UV, and accepts dyes. It is most commonly used for sports and industrial safety frames
What are the advantages of Polycarbonate Frames?
- Virtually unbreakable
- light weight
- can accept limited range of dyes, generally used in clear state
- absorbs UV
What is Polyamide?
A blend of different nylon materials. Each manufacturer has their own special blend.
What are the advantages of Polyamide?
- Durable and adjustable.
- Stronger then acetate and propionate
- Hypoallergenic
- comfortable and light weight
- resistant to solvents, oils, cosmetics and chemicals
- Resistant to climate conditions
- available in all color ranges, from solid to opaque
- Flexible, no plasticizers that dull the finish