If used for other materials these tiny bits must be evaluated for equivalent cutting speed vs material resistance to the cut ( hardness ), as the bit's rake angle and expected feed per revolution are optimised for high-speed automated use on fiberglass PCB substrate.
42.
If a material has a machinability rating of 70 %, it can be determined, with the above knowns, that in order to maintain the same tool life ( 60 minutes ) the cutting speed must be 70 sfpm ( assuming the same tooling is used ).
43.
Pulsed lasers which provide a high-power burst of energy for a short period are very effective in some laser cutting processes, particularly for piercing, or when very small holes or very low cutting speeds are required, since if a constant laser beam were used, the heat could reach the point of melting the whole piece being cut.
44.
"Cutting speed " ( also called " surface speed " or simply " speed " ) is the speed difference ( relative velocity ) between the milling ), the units are typically distance per time ( inches per minute [ in / min or ipm ] or millimeters per minute [ mm / min ] ), although distance per revolution or per cutter tooth are also sometimes used.
