Milling
Cutting Speeds and Feeds, Fluids
The time required to complete a milling operation and the quality of the finish of the machined surface is almost completely governed by the CUTTING SPEED and FEED of the cutter.
MillingCutting Speed refers to the distance, measure in feet, a point (tooth) on the circumference moves in one minute. It is expressed in terms of FEET PER MINUTE (FPM) and is directly dependent on the REVOLUTIONS PER MINUTE (RPM) of the cutter.
Feed is the rate the work moves into the cutter and is given as FEED PER TOOTH PER REVOLUTION (FTR). The selection of the proper feed is probably the most difficult thing for the machinist to determine. In view of the many variables; width of cut, depth of cut, condition of the machine and cutter, etc., feed should be as coarse as possible and consistent with the desired finish.
Consult the mill manual or wall chart for the speeds and feeds required for various materials.
Cutting Fluids serve several purposes. They carry away the heat generated during the machining operation, act as a lubricant and prevent the chips from sticking or fusing to the cutter teeth, and flush away chips. The lubricating qualities also influence the quality of the finish of the machined surface.
UNTIL YOU BECOME PROFICIENT IN THE USE OF THE MILL, CONSULT YOUR INSTRUCTOR OR SHOP PERSONNEL BEFORE STARTING ANY MACHINING!
More information can be found in the reference book “Modern Metalworking”