The Effect of Speed and Feed on the Mechanics of Metal Cutting

Abstract

When the cutting speed or feed of a metal cutting tool is increased, the most striking effect is on the rate of tool wear, but there are other changes which take place at the same time. These are changes in the geometry of the chip, tool forces, and tool build-up and surface finish. An attempt is made in this paper to form a logical theory to explain these variations in the mechanics of the process. The problem of tool wear is not attempted.

A series of tests has been conducted on mild steel and copper, over a wide range of speed, feed, and tool angle; and a theory has been developed. The results arrived at are:—

(1) That local temperature in the chip plays an important part in affecting the friction at the chip tool interface.

(2) For many purposes effects due to speed and feed can be treated as functions of the product of speed and feed.

(3) Temperature does not affect the shear strength of the metal directly.

(4) The extent of built-up edge prevailing can be put as a function of the product of speed and feed.

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