An Overview of Transparent Plastics
Transparent plastics are used primarily when clarity of vision through the material is a concern.
Transparents covered in this section include: Acrylic (polymethlamethacrylate), Butyrate (cellulose acetate butyrate), Lexan (polycarbonate), and PETG (glycol modified polyethylene terphthalate).
Transparent colored materials transmit the portion of the visible spectrum that allows the eye to see the desired color. Most plastic materials are not transparent: however, in this group acrylic transmits 92% of the light available (comparable to glass).
The remainder of this group offers light tranmission rates greater than 80%. All products in this group offer good impact resistance. Acrylics are 17 times more resistant to breakage than glass, and are easily fabricated. PETG has 7 times the impact resistance of acrylic and Lexan has 17 times the impact resistance of acrylic. Also, as an added plus, the light weights of this group of materials allow their use in applications instead of glass. The average weight of this set of plastics is about one-half that of a comparable size of glass.
For abrasion resistance, a coating is available on acrylic and polycarbonate sheet.
Special color tints are available in this group. Acrylics are manufactured in a veritable rainbow of colors. Polycarbonate is produced in standard tints of gray, bronze, black, and the basic clear. The other materials in this group also are manufactured in colors, however, minimum mill runs are required.
Additional attributes of these plastics are their machinability and formability. Most drilling, sawing, and routing can be performed with standard wood working equipment. Heat forming of the products in this group is an added bonus. With these features, this group finds countless industrial applications such as: dust covers, sneeze guards, safety covers, and machine guards.
Materials assigned to this section are used primarily to glaze windows, for signs and lighting fixtures, or as an accessory in a light-transmitting application, such as light transmission with acrylic rod.
Transparents are available in a wide array of configurations, including: sheet, rod, tube, and film.
Materials listed in these web pages are primarily used in applications where thermoforming is the primary process used to obtain the materials finished form.
The materials reviewed include, ABS, ABS-FR, Conductive ABS, Kydx, Noryl, PETG and High Impact Styrene. Other materials which can be thermoformed also include Acrylics and Polycarbonates, and Polyethylene and Polypropylene. However, the materials listed in this section are typically better in overall performance when considering commercial parts such as luggage, electronic, computer and medical equipment housings, etc.
Although the reviewed materials were chosen for their thermoformability capabilities, their properties lend themselves to applications where the manufactured part does not require thermoforming. However, whenever possible, the design engineer should pre-determine ultimately how the product will be manufactured. In many situations, the relative low cost of thermoforming provides manufacturing cost advantages. Any of the products in this category offer a mix of electrical, chemical, and mechanical properties coupled with outstanding thermoforming capabilities.