Wednesday, September 19, 2012
Why Designers Continue To Replace Metal Parts With Engineering Plastics
Mechanical engineers and designers are increasingly replacing existing metals parts with components made from engineering plastics. A common misconception is that this trend is based purely on reducing the initial cost per part, but the reality is quite different. Engineering plastics are often more expensive than metals, but provide benefits such as improved performance, longer part life, and reduced downtime. This long-term, “overall cost of ownership” approach is driving a strong market for engineered plastic solutions.
Here are a few of the product features and benefits that are driving the trend towards increased use of engineering plastics.
In high-wear applications, many plastic materials will outperform brass & other metal bearing materials. Plastics such as Nylon, UHMW, PTFE, Acetal and Turcite® offer natural lubricity to increase wear resistance and extend the part life of bearings, rollers, gears, and seals.
When replacing metal parts, plastics will typically reduce the part weight by 30% to 50%.This can translate to significant energy savings when used in applications such as transportation, linear motion, and material handling.
Plastics, ceramics, and composites have been developed which resist both extremely high & extremely low cryogenic temperature ranges with minimal loss of mechanical properties. Materials such as Celazole® PBI can continually operate at up to 750°F, while materials such as Kel-F® PCTFE can operate at -400°F.
Impact Resistance & Shock Absorption
Many plastics and composites offer excellent impact resistance. Materials such as Polycarbonate are used for impact-resistant glazing and shields. Nylon and Polyurethane will absorb impact shock and isolate stress points to protect surrounding components.
Many plastics have excellent insulation properties, reducing heat, and improving product reliability. Laminates such as G-10/FR-4, GPO-3 and LE Phenolic are used extensively in electrical and transportation industries to insulate from heat and electrical shock. Thermoplastics such as PTFE and Meldin® work well in high-temperature insulating applications.
Metals are inherently susceptible to corrosion from moisture, acids, and organic solvents. Many plastics were designed specifically to combat these problems. Materials such as PVC, CPVC, Polypropylene, and PTFE offer superior corrosion resistance at an economical price.
Many plastics have been approved for use in medical applications ranging from heart pump valves to endoscopic instruments. Products meet FDA, USP Class VI, and ISO 10993 standards. Such materials include Radel®, PEEK, Ultem®, and Polycarbonate.
Dozens of plastic materials have been developed to meet common aircraft, transportation, semiconductor, and UL ratings for flame and smoke safety. Specifications include FAR, FTA, FRA, ASTM, UL and FM. In the semiconductor industry materials meeting the FM-4910 specification have reduced or eliminated the need for costly fire-suppression systems, and thus have reduced overall equipment costs. In some cases, the use of these materials have even reduced insurance costs in high-liability applications. Common flame-retardant and flame-safe materials include: Kydex®, Boltaron®, Halar®, CP7-D, FRPP, Corzan® CPVC, and Kynar® 740 PVDF.
Plastics have long been a crucial product used in the manufacturing of high-purity fluid & gas handling applications. Many plastics have eliminated the concerns of out-gassing, leaching, and other contamination in crucial high-purity systems. These products include: PTFE, PFA, FEP, Halar® and Kynar® PVDF.
Several plastics and composites have anti-static qualities to prevent the build up of an electric charge. Products range from conductive materials 10^2-10^6, and static dissipative 10^6-10^10, to highly resistive materials 10^10-10^12.
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To learn more, contact Professional Plastics, Inc. or please visit www.professionalplastics.com