CAST NYLON 6 BIG PARTS

A large US manufacturer's mining division designed a piece of prototype equipment destined for South America. An integral component on this equipment was a sheave measuring 48 inches in diameter by 18 inches through the bore. The design parameters required the sheave to be light- weight yet durable, corrosion resistant, and capable of operating in a harsh mining environment. Cast Nylon 6 proved to be the solution.

Cast Nylon is produced by direct polymerization of a monomer within a heated mold. This method allows for the manufacture of castings of virtually unlimited size and with minimal internal stress. Fillers and additives can also be introduced into the process, allowing the manufacturer to formulate specialized grades to suit specific end use requirements.

Cast Nylon 6 has long been accepted as a standard in many sheave applications. Common uses range from mobile construction cranes to heavier offshore applications. Cast Nylon's light weight (1/7th that of steel or cast iron), combined with its broad range of physical properties, provide numerous benefits over cast iron and steel in countless applications. The resilient nature of Nylon 6 provides for a larger point contact area between sheave and wire rope, this allows Cast Nylon Sheaves to support loads close to that of it's steel and cast iron counterparts. The lighter Cast Nylon provides for easier installation, greater stability, and higher lifting capacities as considerable boom weight is eliminated.

In addition, the combination of differing mating materials between sheave and wire rope provide for a dramatic increase in rope life. When rope diameters reach 4 inch, as in this application, even a small increase in rope life can lead to big savings.

Engineered components, as large as those shown above, provide few manufacturing options within the engineered thermoplastics family. Cast Nylon 6, having custom-cast capabilities, proved to be the logical choice. Through the use of specialized tooling and Nylatech MD, a roughcasting that was close to the finished component dimensions was made. This reduced the amount of material required by 30%, and saved considerable machining time. Had the individual castings been produced as disks, they would have weighed close to 1800 pounds each. As "custom-cast components" each sheave weighed-in at 1200 pounds, making them two of the largest Cast Nylon Castings ever produced in North America.

Submitted by Nylatech, Inc., manufacturers of cast nylon 6 and 6/12 rod, sheet, tube, bar, and finished and semi-finished custom cast components.

For more information, contact Calvin Petersen, Nylatech, Inc., P.O. Box 455, Everson, WA 98247, 800-506-9566, Fax:360-966-2838, E-mail: nylatech@nylatech.com, Web: www.nylatech.com.