Milling and it's types of operations

       In this content,You can learn about introduction of milling machine operations in production process with it's types.

Milling Operations

Milling is a versatile process by which a large variety of components are produced involving various types of operations. Following are the main milling operations.

(1) Plain milling .

(2) Side and face milling .

(3) Face milling .

(4) Form milling .

(5) Gang milling .

(6) End milling .

(7) T -slot milling .

(8) Slitting .

Milling operations are in details as following:-

(1) Plain milling:-

Plain milling, also called peripheral milling or slab milling, is the process which is used to generate flat surfaces by using the teeth located on the periphery of the cutter.

 In this process the axis of cutter rotation is parallel to the axis of cutter. The cutter has straight or helical teeth straight cutters are used for light duty and helical for heavy duty.

(2) Side and face milling:-

Side and face milling makes use of a cutter that has teeth on the sides and also on the periphery in order to produce slots or for milling flats on round work held vertically.

(3) Face milling:-

Face milling is used for machining a flat surface on the workpiece. In this a milling cutter machines the surface at right angles to the cutter spindle axis and parallel to the face of cutter. 

Face milling may be called a variation of end milling where the cutter has large diameter with several cutting teeth. Face milling cutters are generally over 150 mm diameter and of the inserted tooth type and are mounted directly to the spindle nose. Face mills under 150 mm are called shell mills and are held on a short arbour.

Face milling cutters are made of high speed steels, cast alloys or carbides and are heavy duty cutters. Heavy cuts, coarse feeds and cutting speeds are essential for face milling. Example of face milling is the machining of cylinder heads.

(4) Form milling:-

Form milling is used to machine surface of irregular shapes. The cutter used for this purpose is called"Form milling cutter" and the shape of its cutting teeth conforms to the profile of the surface to be produced. 

Milling of intricate patterns on workpieces is an example of form milling. We may say that in form milling the job profile is the replica of the tool form. Form cutters are disc type HSS cutters.

(5) Gang milling:-

Gang milling is the muting operation in which two or more milling cutters are mounted on the same arbour and are used to mill a number of flat horizontal and vertical surface of a workpiece simultaneously. 

In gang milling all cutters may perform the same type of operation or each cutter may perform a different type of operation.

(6) End milling:-

End milling is the process of machining horizontal, cutting tool is called end mill. In end milling operation, when operation is performed at the end of the workpiece a single flat surface is produced. 

For producing a horizontal surface the axis of rotation of the cutter has to be horizontal, for vertical surfaces it remains vertical and for inclined surface it is to be set at proper inclination with the table top. End milling is used for producing narrow slots, grooves and key ways using end mill cutter.

(7) T-slot milling:-

T -shaped slots are similar to those in milling machine table or shaper table so that work piece can be clamped on the machine table for operation. T -slot milling the operation to produced T-shaped slots in a workpiece. 

Actually T -slot milling is a form of slot milling. In T -slot milling first an open slot from one end of the solid workpiece to its other end, is milled with the help of a suitable cutter (say a plain milling cutter or an end mill). Then the slot is milled to the required T-shape by using a special T -slot cutter.

(8) Slitting:-

Slitting is the operation to cut stocks into various widths for production of flat gages, templets etc. It may also be used for cutting narrow slots and grooves. Slitting operation make use of a slitting saw or slitting cutter. The main factor in a slitting operation is the rigidly of the workpiece.

 An important precaution in this process is to keep the line of cutting in the centre of a T -slot and running along its length. This allows the slitting saw to project safety into the free space in the slot to prevent its teeth from being damaged.

Apart from the above mentioned operations a number of other milling operations are as under:-

• Angular milling .

• Slot and Groove milling .

• Gear milling .

• Thread milling .

• Key way milling .

• Cam milling .

• Helical milling .

• Straddle milling.

Conclusion:-

You have learnt about introduction of milling machine operations in production process and it's types with diagram of milling machine.