Construction of milling machine:A milling machine is so named because it may be adapted to a very wide range of milling operation the table of milling machine is mounted on a circular swiveling bag which has degree graduation, and the table can be swiveled to any angle up to 45 on
either side of the normal position.
The table can be swiveled about a vertical axis and set at an angle other than right angles to the spindle.
Thus in the universal milling machine in addition to three movements as incorporated in a plain milling machine the table may have fourth movement when it is fed at an angle to the milling cutter. This additional feature enable it to perform helical milling operation which can not be done on a plain milling machine unless a spiral milling attachment is used.
The various milling process performed by different milling cutter may be grouped under two separate headings peripheral milling and face milling. The cutting actions of milling cutter to perform the above process are described below.
1. Peripheral milling
The peripheral milling is the operation performed by a milling cutter to produce a machined surface parallel to the axis of the cutter. According to the relative movement between the tool and the work the peripheral milling is classified under two headings:
- Down milling
- Up milling
1. Down milling:
It is the process of removing metals by cutter which is rotated in the same direction of travel of the work piece.
2. Up or conventional milling:
It is the process of metal by cutter which is rotated against the direction of the travel of the work piece.
Milling Machine operation:
The following are different operations performed in a milling machine.
Types of milling:
- Plain milling
- Side milling
- Face milling
- End milling
- Straddle milling
- Gang milling
- Angular milling
- Form milling
- Profile milling
- Gear milling
- Helical milling
- Cam milling
- Thread milling
1. Plain milling:
Plain milling is the process of production of the plain, flat, horizontal surface parallel to the axis of rotation of a plain milling cutter the operation is also called slab milling
2. Side milling:
Side milling is the operation of production of a flat vertical surface on the side of a work piece by using the side milling cutter.
3. Face milling :
The face milling operation is performed by a face milling cutter rotated about an axis perpendicular the work surface.
4. End milling
The end milling is the operation of production of the flat surface which may be vertical, horizontal or at an angle in reference to the table surface. The cutter used in an end mill.
The operation of production of key ways, grooves and slots of varying shapes and size can be performed in a milling machine by using a mills cutter, a metal slitting saw
6. straddle milling
The straddle milling is the operation of production of flat vertical surface on both sides of a work piece by using two side milling cutters mounted on the same arbor.
7. Saw milling
The saw milling is the operation of production of narrow slots or grooves on a work piece by using a saw milling cutter.
8. Gang milling
The gang milling is the operation of machining several surface of a work piece simultaneously by feeding the table against a number of cutters having same or different diameter mounted on the arbor of the machine
9. Angular milling
The angular milling is the operation of production of an angular surface on a work piece.
10. Form milling
The form milling is the operation of production of irregular counters by using form cutter.
11. Profile milling
The profile milling is the operation of production of an outline of a template or complex shape of a master die on a work piece.
12. Gear cutting
The gear cutting operation is performed in a milling machine by using a form relived cutter. The cutter may be cylindrical type or end mill type.
13. Helical milling
The helical milling is the operation of production of helical flutes or grooves around the periphery of a cylindrical work piece.
14. Cam milling
The cam milling is the operation of production of cams in a milling machine by the use of a universal dividing head and vertical milling attachment.
15. Thread milling
The thread milling is the operation of production of threads by using a single or multiple thread milling cutters.
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