It is very similar to a horizontal milling machine in construction as it has the same parts of base, column, knee, saddle and table. The spindle of the machine is positioned vertically. The cutters are mounted on the spindle. The spindle is rotated by the power obtained from the mechanism placed inside the column. Angular surfaces are machined by swiveling the spindle head.
Types of Milling Machine
The milling machines are classified according to the general design of the machine.
- Column and knee type
- Plain milling machine
- Universal milling machine
- Omniversal milling machine
- Vertical milling machine
- Table type milling machine
- Planer type milling machine
- Special type milling machine
Column and Knee Type Milling Machine
The column of a column and knee type milling machine is mounted vertically upon the base. Knee is mounted on the accurately machined guideways of the column. It is designed to move up and down accurately. Saddle and table are mounted on the knee.
There are different types of column and knee type machines.
- Plain Milling Machine – It is rigid and sturdy. Heavy workpieces are mounted and machined on the machine. The work mounted on the table is moved vertically, longitudinally and crosswise against the rotating cutter. The table cannot be rotated. It is also called as horizontal milling machine because the cutter rotates in horizontal plane.
- Universal Milling Machine – The table of a universal milling machine can be swiveled by 45º on either side and so helical milling works can be performed. It is named so because it can be adapted for a very vide range of milling operations.
Various milling attachments like index head, vertical milling head, slot milling head and rotary table can be mounted. It can machine drills, reamers, gears, milling cutters with a very high degree of accuracy and so it finds an important place in a workshop.
- Omniversal Milling Machine – In addition to the table movements obtained in a universal milling machine, the knee can be tilted to a required angle. It is useful for machining helical grooves, reamer and bevel gears. It is mostly used in tool room work.
- Vertical Milling Machine – A spindle of a vertical milling machine is positioned at right angles to the table. The cutter is moved vertically or at an angle by swiveling the vertical head of the machine.
The machine is adapted for machining slots and flat surfaces by moving the table. By mounting end mills and face milling cutters on the spindle, vertical milling and internal milling are preformed.
Differences between a Plain Milling Machine and a Universal Milling Machine
|Plain Milling Machine||Universal Milling Machine|
|1. The table can be moved vertically, longitudinally and crosswise.
2. Helical milling works cannot be done as the tablecannot be swiveled.
3. As there are no special attachments, operations like gear cutting, slotting and vertical milling cannot be performed.
4. It is more rigid and suitable for machining on heavy and large workpieces and for simple milling operations.
5. The cost is less.
| 1. Apart from the three movements of a plain milling machine, it can be swiveled about 45º.
2. The table can be swiveled and helical milling and spiral milling can be performed.
3. Special attachments like indexing head, rotary table, vertical milling attachment, slotting head are available with this machine. So spur gear, helical gear, bevel gear, cutters and reamers can be machined.
4. It is meant for light workpieces. A vide range of operations can be performed in this machine. It is mainly used in tool rooms.
5. It is very costly.