ENGINEERING PLASTICS

Engineering plastics are a group of plastic materials that exhibit superior mechanical and thermal properties in a wide range of conditions over and above more commonly used commodity plastics. Engineering plastics are used for parts rather than containers and packaging. Engineering thermoplastics are sold in much lower quantities and are thus more expensive per unit weight. Despite this, they are widely used in everyday products. Typically, an engineering plastic is chosen for its range of enhanced physical properties e.g. polycarbonate is highly impact resistant and polyamides are highly resistant to abrasion;

Examples of engineering plastics include:
• Polyamides (PA)
• Nylon 6
• Nylon 6-6
• Acrylonitrile butadiene styrene (ABS)
• Polycarbonates (PC)
• Polyoxymethylene plastic (POM / Acetal)

Polyoxymethylene (POM), also known as acetal, is an engineering thermoplastic used in precision parts that require high stiffness, low friction and excellent dimensional stability. POM is characterized by its high strength, hardness and rigidity to ~40 °C. POM is intrinsically opaque white, due to its high crystalline composition, but it is available in all colors. POM advantages:
• High abrasion resistance
• Low coefficient of friction
• High heat resistance
• Good electrical and dielectric properties
• Low water absorption

Usage
• Mechanical gears, sliding and guiding elements, housing parts, springs, chains, screws, nuts, fan wheels, pump parts, valve bodies.
• Electrical Engineering: insulators, bobbins, connectors, parts for electronic devices such as televisions, telephones, etc.
• Vehicle: Fuel sender unit, Light stock, power windows, door lock systems, articulated shells.
• Model: Thin, later claimed Modellbahnen parts, such as bogies and handle bars.
• Medical: insulin pen, Metered dose inhalers
• Furniture: hardware, locks, handles, hinges, or even curtains roles.
• Construction: Structural Glass - pod holder for point
• Packaging: aerosol cans, vehicle tanks.
• Sports: Paintball accessories. It is often used for machined parts of paintball markers that do not require the strength of aluminum, such as handles and reciprocating bolts.
• Clothing: zippers.
• Music: picks, Irish flutes, Bagpipes, Practice chanters, harpsichord plectra, tuba mouthpieces.
• Dining: Fully automatic coffee brewers; knife handles
• Horology: Watch bracelets.

     



 


 

Acrylonitrile butadiene styrene (ABS) - is a common thermoplastic. Its glass transition temperature (ABS is amorphous and therefore has no true melting point) is approximately 105 °C (221 °F). ABS is derived from acrylonitrile, butadiene, and styrene. The advantage of ABS is that this material combines the strength and rigidity of the acrylonitrile and styrene polymers with the toughness of the polybutadiene rubber. The most important mechanical properties of ABS are impact resistance and toughness. Even though ABS plastics are used largely for mechanical purposes, they also have electrical properties that are fairly constant over a wide range of frequencies. While the cost of producing ABS is roughly twice the cost of producing polystyrene, it is considered superior for its hardness, gloss, toughness, and electrical insulation properties. ABS is flammable when it is exposed to high temperatures, such as a wood fire.

Polycarbonates (PC) - are a particular group of thermoplastic polymers. They are easily worked, molded, and thermoformed. Because of these properties, polycarbonates find many applications. Polycarbonate is a durable material. Although it has high impact-resistance, it has low scratch-resistance and so a hard coating is applied to polycarbonate eyewear lenses and polycarbonate exterior automotive components. The characteristics of polycarbonate are quite like those of polymethyl methacrylate (PMMA, acrylic), but polycarbonate is stronger, usable in a wider temperature range, yet more expensive. This polymer is highly transparent to visible light, with better light transmission than many kinds of glass. Polycarbonate is mainly used for electronic applications; The second largest consumer of polycarbonates is the construction industry, e.g. for domelights, flat or curved glazing, and sound walls. A major application of polycarbonate is the production of Compact Discs, DVDs, and Blu-ray Discs. In the automotive industry, injection-molded polycarbonate can produce very smooth surfaces that make it well-suited for direct metalised parts such as decorative bezels and optical reflectors. Many polycarbonate grades are used in medical applications too.

A polyamide is a polymer containing monomers of amides joined by peptide bonds. Polyamides are commonly used in textiles, automotives, carpet and sportswear due to their extreme durability and strength. Polyamide 6 (PA6) and Polyamide 6.6 (PA6.6) are widely used in many different markets and applications due to their very good performance / cost ratios. Many parts are made with these polyamides in the Transportation, Electronics & Electrical, Consumer goods, Building &Construction and Packaging industries. They are by far the most used Polyamide globally. Although they exhibit similar properties some slight differences remain. PA6 has a slightly lower temperature resistance versus PA6.6 and is also slightly less expansive. PA66 is used when PA6 reaches its limit temperature or when the hydrolytic stability of PA6 is not sufficient anymore. It provides good surface appearance and good weld strength leading to burst pressure resistance.