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 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.
