Principle of CNC Operation, Process Planning and Types of CNC Controllers

Principle of CNC Operation

The following are the principles of CNC operation.

• Movement of X, Y, Z axis are controlled by motor which supplies either Alternating current or Direct current.
• Movement of machine is done by giving commands.
• All the operations are carried out by codes like speed, feed, depth of cut, etc.
• For each operation separate code is available.
• Warning system is available to save guard the various operations and components.

Process Planning

The design/development department of a manufacturing industry designs a part and prepares its detailed drawing. For a simple part, three or even two orthographic views are sufficient to describe it fully. However, several sectional and auxiliary views may be needed to completely define a complex part. While designing, the design engineer must have an eye on the production methods also. An inexperienced person may design a part which cannot be easily produced. This may increase the production cost without any improvement in the functionality. So, the objective should be to make a part as simple as possible from production point of view, as long as its functionality does not get affected beyond acceptable limits.

After the drawing is finalized, the programmer carries out the task of process planning. Process planning is the procedure of deciding what operations are to be done on the component, in what order and with what tooling and work holding facilities. So, even though a programmer may not be a skilled machinist, he must have a thorough knowledge of relevant machining operations. He also has to choose cutting parameters such as spindle speed, depth of cut and feed. On an NC/CNC machine, the same operation can be performed in several manners using different G codes. The programmer has to select the best or the most suitable method. He may also like to incorporate planned stops during machining for inspection or some other purpose. An NC/CNC machine does exactly what it is instructed to do. It does not have its own logic or intelligence. For example, it may start a turning operation using a drilling tool, if we make such a mistake in the program. Performance of these machines depends on our programming skill and knowledge of machining operations to quite an extent, though we need not be a skilled worker.

Types of CNC Controllers

Manufacturers, Factories and companies of CNC machine tool adopt various systems or controllers as used are mentioned below.

• Electron per their requirement and easiness. Controllers mostly
• Kirloskar – 15T, 150M,200T
• Sinumeric – HMT/810T/810M
• Hind Numeric
• Fanuc O-T,O-IT
• Siemens
• Duckle
• Ferera