Composite material reinforcement materials. Another important factor is the gross quantity of material to be produced. Large quantities can be used to justify high capital expenditures for rapid and automated manufacturing technology. Small production quantities are accommodated with lower capital expenditures but higher labour and tooling costs at a correspondingly slower rate. Many commercially produced composites use a polymer matrix material often called a resin solution. There are many different polymers available depending upon the starting raw ingredients. There are several broad categories, each with numerous variations. The most common are known as polyester, vinyl ester, epoxy, phenolic, polyimide, polyamide, polypropylene, PEEK,
Spelling of disc in British English. The earlier word is "disk", which came into the English language in the middle of the 17th century. In the 19th century, "disk" became the conventional spelling for audio recordings made on a flat plate, such as the gramophone record. Early BBC technicians differentiated between "disks" (in-house transcription records) and "discs" (the colloquial term for commercial gramophone records, or what the BBC dubbed CGRs). By the 20th century, the "k" spelling was more popular in the United States, while the "c" variant was preferred in the UK. In the 1950s, when the American company IBM pioneered the