About miling machines

Milling machine

A milling machine is a machine tool used for the complex shaping of metal and other solid materials. Its basic form is that of a rotating cutter or endmill which rotates about the spindle axis (similar to a drill), and a movable table to which the workpiece is affixed. That is to say, the cutting tool generally remains stationary (except for its rotation) while the workpiece moves to accomplish the cutting action. Milling machines may be operated manually or under computer numerical control (CNC).

Milling machines can perform a vast number of complex operations, such as slot cutting, planing,drilling, rebating, routing, etc. 

 

Types of Milling Machines according to its general design.

I. Column-and-knee type

The column of a column-and-knee type milling machine is mounted vertically upon the base. Knee is mounted on the accurately machined guideways of the column. It is designed to move up and down accurately. Saddle and table are mounted on the knee. 

• Vertical Milling Machine – a spindle is positioned at right angles to the table. The cutter is moved vertically or at an angle by swiveling the vertical head of the milling machine.
• Universal Milling Machine – the table of a universal milling machine can be swiveled by 45º on either side and so helical milling works can be performed. It is named so because it can be adapted for a very vide range of milling operations.
• Omniversal Milling Machine – In addition to the table movements obtained in a universal milling machine, the knee can be tilted to a required angle. It is useful for machining helical grooves, reamer and bevel gears. It is mostly used in tool room work.
• Plain Horizontal Milling Machine – It is rigid and sturdy. Heavy workpieces are mounted and machined on the machine. The work mounted on the table is moved vertically, longitudinally and crosswise against the rotating cutter. The table cannot be rotated. It is also called as horizontal milling machine because the cutter rotates in horizontal plane.

II. Bed-type milling machine 

In bed type machines, the work table is mounted directly on the bed, which replaces the knee, and can move only longitudinally. These machines have high stiffness and are used for high production work. 

III. Plainer-type milling machine

The general arrangement of these types of machines is similar to that for planers, except that in place of individual tool bits, milling heads are installed. The table of the machine carries the work past the rotating cutter heads, which are individually powered and can be run at different speeds if necessary. As many as four cutter heads can be used, with two mounted on the cross rail and two on the vertical pillars

IV. CNC milling machines or machining centers

Machining centers are designed and built to provide for flexible manufacturing. They can be used to machine just a few parts or large production runs. Programming can be relatively simple and the use of ‘canned’ cycles provides a great deal of versatility.Machining centers are built in either horizontal or vertical configuration.

V. Special type milling machine

Milling machines designed for special objectives like accommodate larger work, make many duplicate parts, locate holes and surfaces precisely, or to do other unusual machining jobs.