1 August 2016

What is boring machine

John Wilkinson invented the first boring machine tool in 1775. The boring operation that is performed on the boring machine also called internal turning.

The boring machine tools used to bore holes in large and heavy parts such as engine frame, steam engine cylinders, machine housing, etc also used screw cutting, turning, planetary grinding, gear cutting. 

The boring process achieves three things:

  • Sizing
  • Straightness
  • Concentricity
Boring machines are designed in the shortest possible time to make a bore and produce the highest possible surface finish and tolerances.

The boring machine is same as drill press bur designed primarily for boring holes in wood with an angular bit.

Types of Boring Machine :
  • Horizontal boring machine 
Table type

Floor type
Planer type
Multiple head type
  • Vertical boring machine
Vertical turret lathe

Standard vertical boring machine
  • Precision boring machine
  • Jig boring machine
Vertical milling machine type

Planer type

Boring operation : 

The boring operation works almost like the operation of turning and can perform the same process of cutting. While many boring machines appear complex, the movement of the machine is in fact very simple. The stock of the spindle is mounted on ways that can move along other axes themselves.

It uses a single point tool to counter a rotating part of the work. The difference is that boring is performed on an existing hole's inner diameter rather than on an existing hole's outer diameter. Machine tools are called boring machines that are used to perform boring operations. It would have features in common with turning machines, although lathes are sometimes used to account, as previously stated. 

It can be horizontal or vertical, as we saw above. The designation refers to the orientation of the machine spindle or works part's axis of rotation. The setup can be arranged in either two ways in a horizontal boring operation shown in the figure below.

The first setup is one where the work is a fixture to a rotating spindle and the tool is attached to a boring bar that feeds into the work. To avoid deflection and vibration during cutting, the boring bar must be very rigid. Boring bars are often made of cemented carbide that is shown in the figure below to achieve high stiffness. 

The second setup is one that mounts the tool to a boring bar and supports and rotates the boring bar between centers. A feeding mechanism that feeds it past the tool is attached to the work. This setup can be used on a conventional engine lathe to perform a boring operation.

For large, heavy workpieces with large diameters, a vertical boring machine is used, usually, the diameter of the workpiece is greater than its length. The part is clamped to a machine base rotating worktable shown below. There are worktables with a diameter of up to 40 ft. The typical boring machine can simultaneously position and feed several cutting tools. 

The tool heads used on a vertical boring machine often include turrets for several cutting tools. This leads to a loss of difference between this machine and a vertical turret lathe. Vertical boring mills are also often used for one type of job, while vertical turret laths are used for batch production.