Boring machines are used to enlarge holes. In this article, we will discuss a specific type of boring machine i.e Vertical Boring Machine.
Vertical Boring Machine is also known as Vertical Turret Lathe.
Vertical Boring Machine is used to bore, drill, and cut metal workpieces that are large in size and heavy in weight and cannot be processed in a conventional lathe or milling machine. This machine is used for processing large workpieces.
It is named a vertical boring machine because the workpiece is held on a rotary table that rotates about its vertical axis while the tool remains stationary except for the feeding operation. Vertical Boring Machine looks like a vertical lathe.
Vertical Boring Machine is also called Production Machine because multiple tools can be used at a time in this machine and hence the production rate increases.
in this machine, more than one surface of the workpiece can be machined simultaneously at a time.
Parts Of Vertical Boring Machine:
1) Bed: The bed is present at the bottom and is the base of the vertical boring machine. The bed supports every component of the machine.
2) Vertical Columns: Two vertical columns are on both sides of the vertical boring machine. These vertical columns are mounted on the bed.
3) Cross Rail: Cross rail moves vertically up and down on the guideways of the vertical columns. This cross rail is mounted on both vertical columns. It is called cross rail because it moves across in guideways. This cross rail can be set on any position vertically by moving up or down and fixing at the required position.
4) Spindle Head: The spindle head is also known as the tool head or headstock. The spindle head slides on the guideways that are present on the vertical column and cross rail.
This spindle head can move upward and downward and it can also go forward and backward. This spindle head can also be rotated at a certain angle.
There are two types of spindle heads in this machine:
i) Vertical Slide which moves on guideways of the vertical column: Two vertical slides or spindle heads are present on the cross rail. These vertical slides can also be moved up and down using cross rail. It can move horizontally on the guideway of the cross rail and it can also be set at an angle to give an angular cut on the workpiece.
In total, four spindle heads can be mounted head on the vertical boring machine. Two on the vertical column and two on the cross rail.
ii) Spindle Head which moves on guideways of Cross Rail:
Two spindle heads are there on the two vertical columns that move up and down on the vertical column. These spindle heads can move forward and backward as well and can be set at an angle. There is one spindle head on each of the vertical column
4) Tool Post: The tool post is mounted on the cross rail. The tool post is used to hold the boring tool in a vertical boring machine. One or two tool posts can be used as per requirement.
The tool post moves sideways towards the left or right on the cross rail. Guideways are also made on the cross rail for the tool post to move.
5) Supporting Arm:
On the top, there is a supporting arc present between the two columns. This supporting arc supports the two columns so that these columns do not bend or get inclined during the working of the vertical boring machine.
6) Circulatory Table:
The circulatory table is one of the most important parts of the vertical boring machine. This circulatory table rotates on its vertical axis. In other machines, the tool rotates but as large workpieces are to be worked on the vertical boring machine so the table is made to rotate.
The circulatory table rotates on the horizontal plane.
In this machine, the tool is stationary and does not rotate.
There are T-slots on this circulatory table in which the clamping device is fixed.
7) Clamping Device:
The clamping device is fixed on the T-slot of the circulatory table. This clamping device is used to hold the workpiece.
Working Of Vertical Boring Machine:
The workpiece is fixed on the circulatory table either by using a clamp or T Hold or Angle Plate. But if mass production is to be done the boring chuck is used.
Usually, large and symmetrical workpieces are to be worked on the vertical boring machine. Examples of such workpieces are pressure vessels, machine tool tables, casting for steam turbines, locomotive wheels, and turbine runners.
After fixing the workpiece, the cross rail is adjusted and tool post the boring tool is brought near the workpiece.
During the working of this machine, the tool remains stationary and the workpiece rotates.
Then the rotation of the circulatory table is started. As the table rotates the workpiece also rotates and then the boring tool is brought into contact with the workpiece and the required boring operation or other operation is performed.
This boring tool is used to enlarge the internal diameter of the workpiece. This machine can also be used for external operations like providing the surface finish.
Various types of operations can be performed on this machine:.
* The roughing operation can be performed using the roughing tool.
* Internal and external roughing and turning can be done.
But mostly this machine is used to enlarge the holes. To enlarge the holes boring tools or milling cutters are used ad a reamer tool is used to give a surface finish to the internal diameter.
In this machine, the overhang is minimum as a large-size rotary table is used and the workpiece is held properly and as the overhang is minimum so chances of bending of the spindle are very less.
The maximum size of the workpiece that can be machined in this machine is equal to the diameter of the rotary table.
Advantages Of Vertical Boring Machine:
1) Multiple tools can be used simultaneously in the case of a Vertical Boring Machine which increases the production rate.
2) Virtual Boring Machine can handle workpieces of larger diameter which can not be handled by the largest engine lathe.
3) In this machine, the workpieces are mounted on the table instead of the spindle, so it eliminates the chance of bending of the spindle.
Disadvantages of Vertical Boring Machine:
1) Virtual Boring Machine with multiple tools is difficult to locate.
2) This machine can only be used for circular cuts.
Applications of Vertical Boring Machine:
1) It is used for the enlargement of an existing hole.
2) It is used for machining the internal and external diameters of the workpiece.
3) It is used for different machining processes like machining of gear blanks, steam turbine casting, water turbine runners, pressure vessels, flanges for large pipes, and locomotive tires.
4) It is also used for machining faces of large machining components.
Types of Vertical Boring Machines:
1) Standard Vertical Boring Mills
2) Vertical Turret Lathes
3) Vertical Precision Boring Machines
Specifications Of Vertical Boring Machine:
Vertical Boring Machine is specified based on the following:
1) Type of machine tool
2) Size of the table
3) Height of the column
4) Diameter of the spindle bore
5) Range of speed
6) Range of automatic feed.
7) Power Of Motor
8) Space required
9) Maximum gap between rotary table and cross rail