Cast nylon polyamides, commonly called nylon type 6, or PA6 C are available in standard stock shapes and cast in the form of sheet, rod and tube. Cast nylon polyamides are highly molecular, highly crystalline polymers. Semi finished nylon type 6 shapes are manufactured using a casting method, whereby the raw material caprolactam polymerises by means of a controlled chemical reaction.
By using additives such as oil, solid lubricants or thermal stabilisers, the typical characteristics of type 6 nylon can be selectively adjusted for certain applications, opening up a custom tailored range of materials to cover a wide application spectrum. Cast Nylon demonstrates even higher crystallinity and better machinability than extruded nylon.
Extruded Polyamide material, commonly called Nylon plastic, is manufactured in standard stock shapes for machining and is extruded in sheet, rod and tube. The most common extruded nylon is a polyamide 66, which offers a balanced combination of performance and cost that provides users with a unique engineering plastic polymer. Nylon was the first engineering resin and is used in a wide field of applications ranging from electronic, marine, and automotive industries, to fibers used to make carpet. Extruded Nylon 66 has outstanding wear resistance and low frictional properties whilst also exhibiting very good temperature, chemical and impact properties.
PA material, polyamide or commonly called nylon, is manufactured in standard stock shapes for machining in sheet, rod and tube. There are often numbers associated with nylon plastics types such as 6, 66, 12 and 46. These numbers relate to the molecular structure of the nylon polymer and each structure type will have different properties. The most common polyamide plastics are Nylon 6 extruded, cast PA 6 and Nylon 66 (PA66).
Generally speaking, PA Nylon is a semi crystalline thermoplastic with low density and high thermal stability. Polyamides are among the most important and useful technical thermoplastics due to their outstanding wear resistance, good coefficient of friction, and very good temperature and impact properties. In addition, nylon polyamide exhibits very good chemical resistance and is an especially oil resistant plastic. This excellent balance of properties makes the PA polymer an ideal material for metal replacement in applications, such as automotive parts, industrial valves, railway tie insulators and other industry uses, whose design requirements include high strength, toughness and weight reduction. Nylon plastic shows a propensity to absorb moisture and thus has poorer dimensional stability than other engineering plastics. Polyamide properties vary from the hard and tough PA 66 to the soft and flexible PA 12. Depending on the type, polyamide products absorb differing amounts of moisture, which will, in turn, affect the nylon properties, in addition to the dimensional stability of the finished machined part.
Furthermore, there is a distinct difference between nylon shapes produced by extrusion and those produced by casting. Extrusion typically provides for smaller, higher volume machined parts, while casting typically allows for low volume, larger parts containing lower levels of internal stress. Both extruded and cast nylons can be modified through the use of fillers to enhance certain properties.
Information courtesy of Ensinger®