Definition of Milling Machines and its types | Working principle Application parts of Milling Machine

Definition Of Milling Machine

The workpiece is fed past a rotating multipoint cutter on a milling machine, which removes material from the workpiece. Due to the cutter's high speed and numerous cutting edges, the rate of metal removal is significantly higher.

The fact that almost all operations can be carried out on it with high accuracy makes it the most significant machine in the tool room.

By adding more teeth to the cutter, MRR (Material Removal Rate) can be raised even further.

Example:

1. drilling
2. slotting
3. making circular profile
4. gear cutting

Milling Machine Application or Uses

For flat surfaces, slots, and contoured surfaces, milling machines are used. Additionally, it can be used to create complex and irregular surfaces, revolution surfaces, gear cutting, and internal and external thread machining. Machining helical surfaces with different cross-sections, among other things.

Milling Machine Parts

Base, Column, Knee, Saddle, Table, Over-Arm, Spindle or Arbor, Arbor supports, Ram, Machine vice, Cutting tool, and Motor make up a milling machine.
We'll examine each in depth one by one.

You can easily see its parts in this diagram of a milling machine.

1. Base

The component on which the components of the entire machine are mounted is the base. It functions as a certain kind of machine foundation.

Cast iron makes up the majority of the base, giving it good strength and rigidity. Additionally, it aids in shock absorption. The base can also be used to store cutting fluid.

2. Column

The vertical Column serves as a structural element for the miller. Its hollow construction serves as a housing for the milling's driving mechanism and related parts.

In addition, the machine's speed can be adjusted using this driving mechanism to meet our needs.

3. Knee

The knee's shape resembles the human body's knee quite a bit. This crucial component of the machine supports the saddle and table, among other components.

The elevating screw is a height-adjustable part that allows the knee to be raised and lowered by applying manual pressure to the handle. It can be used to modify the entire setup in accordance with the needs of the operator and the nature of the workpiece.

4. Saddle

The saddle, which also supports the table, is present on the top of the knee. Its primary job is to hold up the table.

On the guideways that are precisely 90 degrees from the column face, a saddle can slide. On guideways that are built into the knee, the saddle moves crosswise (in or out).

5. Table

The Table, a long, rectangular piece with grooves, sits on top of the saddle. The Table serves as a platform for holding workpieces and is horizontally slid able. The workpiece will be held in place while being machined by the slots (also known as T-slots or Machine Vice) over the Table.

6. Overhanging arm

One of the components of the miller is the overhanging arm, which is a metallic arm that is attached to the column at one end and free at the other. The overhanging arm is attached to the spindle or arbor.

7. Spindle or Arbor

The spindle is located at the top of the column. The multipoint cutter is attached to the spindle, which is another crucial component of the device.

Through the belt, gear, and clutch assembly, the motor supplies the force needed to turn the spindle.

8. Machine Vice

The tool used to hold the workpiece during milling operations is called a machine vice. It is difficult to complete the task because as the multi-point cutting tool rotates during the milling process, the workpiece will move and change its position. Therefore, the machine vice is used to securely and tightly hold the workpiece.

9. Cutting Tool

The Cutting Tool is an essential part of milling because it is its cutting point or edges that actually remove material from the workpiece. Depending on the type of milling machine, the cutting tool used during the milling process will vary.

10. Motor

The use of a motor to transform electrical energy into mechanical energy is a well-known fact. In order to shear the material and remove it during the milling process, the motor is used to rotate the cutting tool (or multi-point cutting tool).

Working principle of Milling Machine

A milling machine is used to remove metal, with the work being firmly clamped on the machine's table and a rotating cutter with many teeth mounted on the arbor.
While the cutter rotates quickly, the work is fed slowly through it.
Depending on the type of milling machine being used, the work can be fed in a vertical, longitudinal, or cross direction. 
The cutter-teeth remove metal from the job's (workpiece's) surface as it is being done in order to create the desired shape.

Classification of Milling Machine

The operation and type of multi-point cutting tool employed determine the classification. Each workpiece will differ in size and shape depending on the application; as a result, the machining will also differ depending on the application, which could have an impact on the milling operation and milling machine design. According to their classifications, there are various types, and they


1. Column And Knee Type Of Milling Machine

Vertical
Horizontal
Universal

2. Fixed Type Of Milling Machine

Simplex
Duplex
Triplex

3. Special Milling Machine

Rotary Table
Tracer Controlled
Pantograph
Planetary
CNC Milling Machine
Drum

Column And Knee Type Of Milling Machine

i) Vertical Milling Machine

The spindle axis of the vertical mill is arranged vertically, and it rotates around that axis only. Additionally, the spindle can be extended to carry out tasks like drilling and cutting. Turret mill and bed mill are two additional subcategories of vertical mill.

To cut the material, the turret mill has a table that moves both perpendicularly and parallel to the spindle axis. But the spindle remains still. By adjusting the knee and lowering or raising the quill, two cutting techniques can be used with this.

The other is a bed mill, in which the spindle and table move parallel to each other and perpendicular to the spindle's axis.

ii) Horizontal Milling Machine

A common type of miller is the horizontal type of milling, also known as a plain milling machine. Similar to a regular miller, the multi-point cutting tool is fixed to an arbor that is horizontal and perpendicular to the table.

The workpiece can be fed against the cutting tool by moving the table in three different directions: vertical, horizontal, and cross.

iii) Universal Milling Machine

In contrast to the horizontal type, the Universal Milling Machine can move in four directions. By modifying the attachments and fixtures, such as Lathe Machine Operation, the Universal Miller can be made more sophisticated and capable of carrying out various slotting operations.

The Spindle is vertical or parallel to the Table, just like a vertical milling machine. The workpiece can be fixed and fed against the tool on the table using Machine Wise, which is where the tool is operated. Additionally, by utilising various fixtures and attachments, the Universal Miller is capable of performing cuttings for bevel gear, spiral gear, spur gear, twist, and reamer.

Fixed Type Of Milling Machine

i) Simplex Milling Machine

A Simplex Type is capable of simple operations. However, the machine can only move in one direction when it comes to movement. The vertical type of milling machine, in which the cutter is fixed to the Head or Spindle, is similar in construction

ii) Duplex Milling Machine

The duplex machine has two heads, as the name suggests. It is made up of two spindles that revolve parallel to the table (or the surface of the earth). The Spindles were built across from one another, with some room between them.

The workpiece can be supported on the Table, which is built between the two spindles. Both sides of the workpiece can be machined, which is faster and takes less time. It is expected that only large workpieces will be able to be machined over it due to its design.

iii) Triplex Milling Machine

Triplex refers to three. The Triplex Milling Machine, as its name suggests, is built with three heads and spindles. The Spindle is built on two sides of the Table in the Duplex Type.

 Similar to the Triplex Miller, which has two Spindles on the right and left sides of the Table and another that will be built over the top of the Table. Therefore, the workpiece can also be machined on the top side.

The workpiece can have a good surface finish, a quicker machining process, and accurate output thanks to the Triplex Milling Machine type.

Special Milling Machine

I) Tracer

The operation can be carried out by the Tracer Milling Machine by tracing the elements. This kind of machine tool copies and produces the elements using tracer control.

This miller, which is used in the automotive and aerospace industries, can handle milling operations on complex and irregular shapes.

ii) Pantograph

Another type of miller that can produce replicate models is the pantograph milling machine. The miller is pre-defined with the dimensions, shape, size, etc. to carry out the milling operation.

iii) Planetary

In a planetary milling machine, the tool rotates around the workpiece to cut the material. The workpiece can thus take on a cylindrical shape.

iv) Drum

Another type of miller is a drum-shaped cutter with cutting edges called a drum milling machine. The drum miller is made horizontally so that the workpiece can be cut by the rotation of the drum.

The jobs are continuously machined one by one in this kind of continuous process. The drum is rotated at slow speeds because of its size.

v) Rotary Table

A rotary table that can rotate while carrying out a cutting operation is part of the Rotary Table Milling Machine. The cutting tool is fixed perpendicular to the rotary table, just like in Vertical and Universal Types, and the table can be moved up and down (vertically) in order to adjust and feed the workpiece over to the cutting tool.

The Chuck in the Lathe Machine, which is used to centralize and fix the workpiece, resembles the Machine Wise in appearance.

vi) CNC Milling Machine

Computer Numerical Control standards. The CNC is fully automatic, and it is programmed to operate in accordance with the size and shape of the workpiece. Once the workpiece has been inserted into the machine, the machine itself controls the entire process, including changing the tools, direction, speed, etc.

The finished product from the CNC Miller will have accurate dimensions, a good surface finish, and high-quality workmanship.