1) Operational principle

Drilling with a Milling Machine

Since a milling machine can perform exact positioning, a drilling process can be carried out to an exact position. It’s more efficient to process it using a drilling machine, if it’s easy drilling process. However, when correctness is required of the position of the holes, or when there are many holes, the milling machine is suitable. Moreover, it is also the characteristics of the drilling with the milling machine that the taper drill of a large diameter can be used. Generally, we make a drill with the milling machine, when the position of the holes needs high accuracy. In order to get the accuracy, it is needed to the positioning of the original point, and using a center drill is better before a drilling.

INSTRUCTIONS HOW TO USE A MILLING MACHINE
The process of machining flat, curved, or irregular surfaces by feeding the workpiece against a rotating cutter containing a number of cutting edges is milling. The usual Mill consists basically of a motor driven spindle, which mounts and revolves the milling cutter, and a reciprocating adjustable worktable, which mounts and feeds the work piece. Basically milling machines are classified as vertical or horizontal and these types of machines also classified as knee-type, ram-type, manufacturing or bed type, and planer-type. Most of the milling machines have self-contained electric drive motors, coolant systems, variable spindle speeds, and power-operated table feeds.

KNEE-TYPE
Knee-type mills are characterized by a vertically adjustable worktable resting on a saddle which is supported by a knee. The knee is a massive casting that rides vertically on the milling machine column and can be clamped rigidly to the column in a position where the milling head and milling machine spindle are properly adjusted vertically for operation.
The plain vertical machines are characterized by a spindle located vertically, parallel to the column face, and mounted in a sliding head that can be fed up and down by hand or power. Modern vertical milling machines are designed so the entire head can also swivel to permit working on angular surfaces.
The turret and swivel head assembly is designed for making precision cuts and can be swung 360° on its base. Angular cuts to the horizontal plane may be made with precision by setting the head at any required angle within a 180°arc.
The plain horizontal milling machine's column contains the drive motor and gearing and a fixed position horizontal milling machine spindle. An adjustable overhead arm containing one or more arbor supports projects forward from the top of the column. The arm and arbor supports are used to stabilize long arbors. Supports can be moved along the overhead arm to support the arbor where support is desired depending on the position of the milling cutter or cutters.
The milling machine's knee rides up or down the column on a rigid track. A heavy, vertical positioning screw beneath past the milling cutter. The milling machine is excellent for forming flat surfaces, cutting dovetails and keyways, forming and fluting milling cutters and reamers, cutting gears, and so forth. There are many special operations can be performed with the attachments available for milling machine use. The knee is used for raising and lowering. The saddle rests upon the knee and supports the worktable. Saddle moves in and out on a dovetail to control cross feed of the worktable. The worktable traverses to the left or right upon to the saddle for feeding the work piece past the milling cutter. The table may be manually controlled or power fed.
UNIVERSAL HORIZONTAL MILLING MACHINE
The most basic difference between a universal horizontal milling machine and a plain horizontal milling machine is the addition of the table swivel housing between the table and the saddle of universal machine. This permits the table to swing up to 45° in either direction for angular and helical milling operations. The universal machine can be fitted with various attachments such as the indexing fixture, rotary table, slotting and rack cutting attachments, and various special fixtures.
RAM-TYPE MILLING MACHINE
The ram-type milling machine is characterized by a spindle mounted to a movable housing on the column and to permit positioning to the milling cutter forward or rearward in a horizontal plane. Two most popular ram-type milling machines are the universal milling machine and the swivel cutter head ram-type milling machine.
UNIVERSAL RAM-TYPE MILLING MACHINE
The universal ram-type milling machine similar to the universal horizontal milling machine, the difference being, as its name implies, the spindle is mounted on a ram or movable housing.
SWIVEL CUTTER HEAD RAM-TYPE MILLING MACHINE
The cutter head containing the milling machine spindle is attached to the ram. The cutter head can be swiveled from a vertical spindle position to a horizontal spindle position or can be fixed at any desired angular position between vertical and horizontal. The saddle and knee are hand driven for vertical and cross feed adjustment while the worktable can be either hand or power driven at the operator's choice.