What Is a General Purpose Lathe?
A lathe is a type of machine tool for metalworking. The workpiece is fixed to a rotating base called a chuck, and a cutting tool called a bite is applied to the workpiece to cut it into the desired shape.
There are various types of lathes, but they are classified into general-purpose lathes, where the machining is done by hand, and NC lathes, where the machining is done automatically by numerical control programs.
General purpose lathes, also called ordinary lathe, is the most basic lathe, consisting of a spindle head, bed, tailstock, feeder, and reciprocating table.
Uses of General Purpose Lathe
Lathes are used for processing cylindrical and conical shapes using cylindrical or bar materials, boring, and threading.
In factories and other manufacturing sites, NC lathes equipped with NC (numerical control) numerical control devices are the most common type of lathe. This is because NC lathes are suitable for mass production as they perform machining based on coordinates set according to a program.
However, NC lathes cannot handle changes or additional machining during operation. However, general-purpose lathes are used for prototypes and custom-made products that require individual adjustments during machining.
General-purpose lathes are also suitable for small lot production because they do not require the creation of a program for machining.
Features of General Purpose Lathe
The cutting process using a general-purpose lathe is as follows.
First, appropriate cutting tools (bites) are selected according to the size, material, shape, and processing details of the workpiece, and processing conditions such as spindle speed are determined.
Next, the workpiece is fixed in the chuck. The tool is fixed to the tool rest on the reciprocating table by adjusting the tool so that the height of the cutting edge matches the center height.
After shaving the end face of the workpiece to make it flat (face grinding), the center drill is set on the tailstock and brought close to the workpiece. The drill is then set in the center of the workpiece (centering). After setting the machining standard, lathing is performed according to the drawing.
A general-purpose lathe does not need to create a machining program as NC Lathe does, allowing for work to start immediately. General-purpose lathes offer the advantage of allowing modifications and additions to be made during the machining operation. This means that mistakes can be promptly corrected, and since the machining is manual, any wear or defects in the tooling can be readily identified and addressed.
On the other hand, a general-purpose lathe requires a high level of skill because it is processed by hand, and the speed and accuracy of processing varies depending on the skill level of the operator. In addition, since everything from setting the workpiece and byte to lathe machining is done by hand, work efficiency is low, and the lathe is not suited for mass production.