Machining of External Cylindrical Surfaces
Cylindrical surfaces are popularly machined on lathes, shapers, planers and special purpose machines. However, they can also be machined in various other machines such as milling machines and grinding machines. Depending upon the operation required and the machine to be used, the workpiece and tool must be held and controlled properly.
A cylindrical surface is a three-dimensional surface formed by rotating a line around a given point. It is also referred to as an external cylindrical surface, since it is the external surface of a cylindrical geometrical object. The rotational axis is called the axis of rotation and the point around which the line is rotated is called the center point. The distance between the center point and the line is known as the radius of the cylindrical surface.
In the machining of external cylindrical surfaces, the workpiece is usually rotated while the cutting tool is fed to the workpiece along its longitudinal axis. This is done by adjusting the spindle speed of the machine, the feed rate and the depth of cut.
The common machining operations used to machine external cylindrical surfaces include turning, facing, and boring. Turning is used for producing grooves and turning certain shapes on the surface of the workpiece. Facing is used for producing flat surfaces on the workpiece and also for chamfering and grooving. Boring is used for producing holes on the workpiece.
The most common tool used for machining edges or grooves on external cylindrical surfaces is a single-point cutting tool. It is a tool used for machining flat surfaces and contours. The tool has a head shaped like a cone which can be attached to a holder and a shank. The cutting action is provided by the head which has teeth that are machined to a given shape.
The other tools used for machining external cylindrical surfaces include belt sanders, lathe cutters, and reamers. Belt sanders are used to shape and polish cylindrical surfaces. Lathe cutters are used to produce circular cuts and contours on the surfaces of the workpiece. Reamers are used to finish holes made by the cutting tools.
Cylindrical surface machining also involves the use of grinding and abrasive machining processes. Grinding is a process which uses grinding wheels to achieve a smooth finish on the surface of the workpiece. It is used for producing flat and contoured surfaces. Abrasive machining is a process which uses abrasive machining techniques to produce highly commendable surfaces on the workpiece.
In order to obtain the desired finished product, it is important to perform the machining operations in the correct sequence and with the right cutting parameters. The most important factors in the machining of external cylindrical surfaces are the speed, feed and depth of cut. Another important factor is the choice of the cutting tool. The quality of the finished product also depends on the machine tool and its capability.
External cylindrical surfaces can also be machined using Computer Numerical Controlled (CNC) machines. CNC machines are computer-controlled machines which are programmed by inputting instructions that are fed to the machine through a keyboard or a special software. This makes the machining process faster and more accurate since parameters such as the speed and feed rate are accurately calculated and programmed into the machine.
In conclusion, the machining of external cylindrical surfaces involves the use of various tools and specialized machines. Turning and facing are the most common machining operations used to achieve a desired finish on the surface of the workpiece. The choice of cutting tool and machining sequence are very important factors in the successful machining of external cylindrical surfaces. CNC machines are also gaining popularity due to their faster machining speed and precision.
