Free cam feeds
Of course, in reality those other variables are dynamic and not negligible; but there is still a correlation between power available and feeds and speeds employed.
In practice, lack of rigidity is usually the limiting constraint.
It is known that B1112 has a tool life of 60 minutes at a cutting speed of 100 sfpm.
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).
The following table gives the cutting speeds for a selection of common materials under one set of conditions.
The American Iron and Steel Institute (AISI) determined machinability ratings for a wide variety of materials by running turning tests at 180 surface feet per minute (sfpm).It then arbitrarily assigned 160 Brinell B1112 steel a machinability rating of 100%.The machinability rating is determined by measuring the weighed averages of the normal cutting speed, surface finish, and tool life for each material.The phrases "speeds and feeds" or "feeds and speeds" have sometimes been used metaphorically to refer to the execution details of a plan, which only skilled technicians (as opposed to designers or managers) would know.Cutting speed may be defined as the rate at the workpiece surface, irrespective of the machining operation used.