What is Capstan Lathe?
Capstan lathe is the modified form of the engine lathe and center lathe in which the tailstock is replaced with a hexagonal turret tool head. It was first developed by Pratt and Whitney in America in 1860.
It was necessary to develop a capstan lathe because there was only one tool holder in the center lathe and only one tool can be mounted in the tailstock. As a result, it was very time-consuming every time we had to change the tool while changing the operation to be performed on the workpiece. Center lathe was not suitable for mass production.
To overcome these problems, a capstan lathe was developed. capstan lathe is a modified form of the center lathe. This turret tool head has 6 different tool types. The turret tool is rotated to obtain the required tool for the operation.
It is used in mass production, i.e. to manufacture a large number of end products with the highest accuracy and precision in the shortest possible time.
It is a semi-automatic lathe. It is called semi-automatic because the machining processes such as drilling, facing, thread cutting, turning, etc. are carried out automatically without changing tools, while other works such as workpiece clamping, toolset, and cooling are carried out manually.
Working of Capstan Lathe
Six tools are available in the hexagonal tool holder in the capstan lathe. First, the workpiece, which is to be changed into the desired shape and size, is placed in the chuck.
This chuck can be a three-jaw or four-jaw chuck. This workpiece rotates with the chuck, which is connected to a spindle.
The hexagonal tool head has six different surfaces to accommodate six different tool types.
When the workpiece with the chuck starts to rotate, the hexagonal tool head is moved towards the workpiece by moving the saddle. This hexagonal tool head can be rotated and by turning the tool required for machining is directed towards the workpiece.
After the required tool faces the workpiece, the tool is brought into contact with the workpiece by advancing the ram and the required operation is carried out.
After the first operation has been completed and the ram has been moved backward, the turret automatically switches on and the tool mounted on the next face comes into operation.
What is Turret lathe?
A turret lathe is a type of metalworking lathe that’s characterized by the use of interchangeable cutting tools. Like traditional lathes, it presses a stationary cutting tool against a rotating workpiece.
Turret lathes are unique, however, because of their interchangeable cutting tools. The cutting tool can be quickly changed to accommodate a specific manufacturing application.
It evolved from earlier lathes with the addition of the turret, which is an indexable toolholder that allows multiple cutting operations to be performed, each with a different cutting tool, in easy, rapid succession, with no need for the operator to perform set-up tasks in between (such as installing or uninstalling tools) or to control the toolpath.
Benefits of Turret Lathes
Turret lathes are more versatile than traditional lathes because of their interchangeable cutting tools. Traditional lathes also often support multiple cutting tools, but these are more difficult to change than turret lathes.
To change the cutting tool in a traditional lathe, a worker must detach the existing cutting tool, remove it from the lathe, and then reattach another cutting edge.
Turret lathes, on the other hand, can be equipped with several cutting tools at the same time. The cutting tool does not need to be replaced. Rather, the turret lathe can automatically switch to the appropriate cutting tool, which leads to faster and more efficient production processes for manufacturing companies.
It takes only a few seconds for a turret lathe to be switched to a different cutting tool, while it takes a human worker several minutes to manually change the cutting tool in a traditional lathe.
Types of Turret Lathes
There are many different types of turret lathes. For example, some turret lathes are numerically controlled (NC) while others are computer-controlled (CNC). NC turret lathes are older and usually use punch cards or similar rudimentary control methods.
In comparison, CNC turret lathes are newer and use more advanced control methods that require the use of a computer. Turret lathes can also be classified according to how they work. There are automatic turret lathes that can perform a variety of processes with little or no manual labor.
There are also manual turret lathes that require at least some manual labor. Other common types of turret lathes are semi-automatic, vertical, and flat lathes.
Difference between capstan and turret lathe
Capstan and Turret lathes are the advancements of the Engine lathes and center lathes in which the tailstock is replaced by a hexagonal turret tool head with 6 different tools in the turret where the turret tool is rotated according to process requirements in each operation.
The capstan and turret lathe although appear to be identical at first sight but a lot of differences in construction, operation, and use. In this article, you can check it out some difference between these two lathe machines.
|1. Lightweight machine.
|1. Heavyweight machine.
|2. These are usually horizontal lathes.
|2. Turret tool head is directly fitted on the saddle and both of them appear like one unit.
|3. Turret head is mounted on a slide called ram which is mounted on the saddle.
|3. Suitable for heavier chucking work.
|4. Suitable for bar work.
|4. The saddle is moved to provide feed to the tool.
|5. The saddle is locked at a particular point and the ram is moved to provide feed to the tool.
|5. They are heavy and durable.
|6. Only a limited amount of feed and depth of cut is provided for machining.
|6. More feed and depth of cut are provided for machining.
|7. The cross slide is mounted on a carriage that rests on the bed ways between the headstock and the ram.
|7. Some turret-type lathes are equipped with side hung type carriage.
|8. The turret tool head is indexed automatically.
|8. To index the turret tool head, a clamping lever is released and the turret is rotated manually.
|9. Feed stop screws are used to control the distance of tool movement which is at the rear side of the turret.
|9. Limit dogs are used to control the distance of tool movement.
|10. No such facility to moving turret at right angles.
|10. Some turret lathes have the facility of moving the turret at right angles to the lathe axis.
|11. Feed rod gives for longitudinal feed.
|11. Feed rod does not give for longitudinal feed.
|12. Used for mass production of small size equal part.
|12. Used for mass production of large size equal part.
|13. It has hand-operated collet chucks.
|13. It is accommodated with power chucks.
|14. Heavy cuts on the workpiece can’t be given because of non-rigid construction.
|14. Heavy cuts on a workpiece can be given because of the rigid construction of a machine.