Defination Milling Machine its Types and it uses

DEFINATION OF MILLING MACHINE:

Milling machine is a process that can perform in which cutting tool remove material from the workpices present in the direction of angle of the tool axies with tyhe help of milling machine many peration canperformed by small object top the large ones.

Milling

Introduction

Milling is the process of machining flat, curved, or irregular surfaces by feeding the work piece against a rotating cutter containing a number of cutting edges. 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.

Milling machines are basically classified as vertical or horizontal. These machines are also classified as knee-type, ram-type, manufacturing or bed type, and planer-type. Most milling machines have self-contained electric drive motors, coolant systems, variable spindle speeds, and power-operated table feeds 


Milling Machine Play Role in Manufacturing Technology

Milling is a process of producing flat and complex shapes with the use of multi-tooth cutting tool, which is called a milling cutter and the cutting edges are called teeth.

The axis of rotation of the cutting tool is perpendicular to the direction of feed, either parallel or perpendicular to the machined surface. The machine tool that traditionally performs this operation is called milling machine.

Milling is an interrupted cutting operation in which the teeth of the milling cutter enter and exit the work during each revolution. This interrupted cutting action subjects the teeth to a cycle of impact force and thermal shock on every rotation. The tool material and cutter geometry must be designed to withstand these conditions. Cutting fluids are essential for most milling operations.

Types of milling

There are two basic types of milling

Down (climb) milling, when the cutter rotation is in the same direction as the motion of the work piece being fed.

up (conventional) milling, in which the work piece is moving towards the cutter, opposing the cutter direction of rotation

Comparison of Up and Down Milling

Down milling, the cutting force is directed into the work table, which allows thinner work parts to be machined. Better surface finish is obtained but the stress load on the teeth is abrupt, which may damage the cutter.

Up milling, the cutting force tends to lift the work piece. The work conditions for the cutter are more favorable. Because the cutter does not start to cut when it makes contact (cutting at zero cut is impossible), the surface has a natural waviness

Milling Operations

Milling of Flat Surfaces

Peripheral Milling

In peripheral milling, also called plain milling, the axis of the cutter is parallel to the surface being machined, and the operation is performed by cutting edges on the outside periphery of the cutter. The primary motion is the rotation of the cutter. The feed is imparted to the work piece.

In peripheral milling the axis of the cutter rotation is parallel to the work surface to be machined

Types of Peripheral Milling

Slab milling

The basic form of peripheral milling in which the cutter width extends beyond the work piece on both sides

Slotting

Slotting, also called slot milling, in which the width of the cutter, usually called slotter, is less than the work piece width.

The slotter has teeth on the periphery and over the both end faces. When only the one-side face teeth are engaged, the operations is known as the side milling, in which the cutter machines the side of the 

Straddle milling

Straddle milling, which is the same as side milling where cutting takes place on both sides of the work.

In straddle milling, two slotters mounted on an arbor work together;

When the slotter is very thin, the operation called slitting can be used to mill narrow slots (slits) or to cut a work part in two.

The slitting cutter (slitter) is narrower than the slotter and has teeth only on the periphery.