Milling Machine

Milling Machine:

Milling machine is one of the best machines in Mechanical World. Milling is that the process of removing metal by feeding the work past a rotating multipoint cutter. In milling operation the speed of metal removal is rapid because the cutter rotates at a high speed and has many cutting edges. Thus the jobs are machined at a faster rate than with single point tools and the surface finish is also better due to multi-cutting edges.

Milling machine is one among the foremost important machine tools in a tool room as nearly all the operations are often performed thereon with high accuracy. The indexing head makes the machine suitable for therefore many purposes as exact rotation of job is feasible by its use. Milling machine augments the work of a lathe and may produce the plain and curved surfaces and also helical grooves etc.

The miller could also be so arranged that the several cutters are mounted on the arbor at an equivalent time, thus increasing the metal removal rate and allowing several surfaces to be machined at the same time. The single set-up thus arranged also ensures accuracy. It is also possible to adopt the machine to 2 position works, in order that one station is loaded while the opposite is being worked on, thus assuring continuous machining.

Further with the variety of milling cutters, the machine can produce a wide variety of flat and formed surfaces. It is possible to have relative motion between workpiece and cutter in any direction and thus mill surfaces having any orientation.

The action of a milling cutter is vastly different from that of a drill or lathe tool. In milling operation, the leading edge of the cutter is kept continuously in touch with the fabric being cut. The cut picks up gradually only.

The cycle of operation to get rid of the chip produced by each tooth is first a sliding action at the start, the cutter comes into contact with the metal then crushing action takes places just after it leading finally to the cutting action. In some metals this peculiar action produces a hardening effect called ‘work- hardening’ which complicates the milling operation considerably, since it throws an increased strain on the teeth of the cutter.

Milling machines are often used for machining flat surfaces, contoured surfaces, complex and irregular areas, surfaces of revolution, slotting, external and internal threads, gear cutting, helical surfaces of varied cross-sections etc. to close tolerances for both limited quantity and production. The versatility and accuracy of the milling process causes it to be widely utilized in modern manufacturing.