Page 575 - Dormer

GENERAL HINTS

MILLING

GENERAL HINTS ON MILLING

Milling is a process of generating machined surfaces by progressively removing a predetermined amount of
material or stock from the workpiece at a relatively slow rate of movement or feed by a milling cutter rotating at a
comparatively high speed.
The characteristic feature of the milling process is that each milling cutter tooth removes its share of the stock in the
form of small individual chips
TYPE OF MILLING CUTTERS
The three basic milling operations are shown below: (A) peripheral milling, (B) face milling and (C) end milling.

A C
B

In peripheral milling (also called slab milling), the axis of cutter rotation is parallel to the workpiece surface to be
machined. The cutter has a number of teeth along its circumference, each tooth acting like a single-point cutting tool
called a plain mill. Cutters used in peripheral milling may have straight or helical teeth generating an orthogonal or
oblique cutting action.

In face milling, the cutter is mounted on a spindle with an axis of rotation perpendicular to the workpiece surface. The
milled surface results from the action of cutting edges located on the periphery and face of the cutter.

In end milling, the cutter generally rotates on an axis vertical to the workpiece. It can be tilted to machine tapered
surfaces. Cutting teeth are located on both the end face of the cutter and the periphery of the cutter body.

DIFFERENT APPLICATIONS FOR END MILLS
The MRR and the applications are strongly related. For each different application we have a different MRR that
increases with the engagement section of the cutter on the workpiece. The recent Dormer Catalogue was produced
with simple icons that show the different applications.

Side Milling Face Milling Slot Milling Plunge Milling Ramping

The radial depth of cut The radial depth of Machining of a slot for It is possible to drill Both axial and radial
should be less than 0.25 cut should be no keyways. The radial the workpiece with an entering into the
of the diameter of the more than 0.9 of the depth of cut is equal end mill only with the workpiece.
end mill. diameter, axial depth to the diameter on the cutting centre. In this
of cut less than 0.1 of end mill. operation the feed
the diameter. has to be halved.

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