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Basic concept of numerical control – driving devices hydraulic systems – DC motors – Stepping motors – Data processing unit – Photoelectric type – Programming –  Part programming – General information – Post processor elements – APT – syntax only (no programming exercise)  – ADAPT/EXAPT, Autospot – Characteristics of N/C system – CNC / DNC – CNC typical system – Block diagram – Interfacing of CNC Machines – Programming of CNC – Adaptive control systems – ACC  – ACO – Basic concepts of Robotics.

Major Components Of CNC:

A CNC machine consist of the following parts

1.Part program:

A part program is a series of coded instructions required to produce a part.It controls the movement of the machine tool and on/off control of auxillary functions such as spindle rotation and coolent.The coded letters are made of letters,symbols and numbers.

2.Program input device:

The program input device is used to enter the part program into the CNC control.Three commonly used input devices are punched tape reader,magnetic tape reader and computer via RS232- communication.

3.Machine control unit:

Machine Control Unit(MCU) is the heart of the CNC system.It is used to perform the following functions

• To read the coded instructions.
• To decode the coded instructions.
• To implement interpolations(linear,circular,helical) to generate axial motion commands.
• To feed the axis motion commands to the amplifier circuit for driving the axis mechanisms.
• To receive the feedback signals of position and speed for each drive axis.
• To implement auxillary control functions such as coolent or spindle on/off.

4.Drive system:

A drive system consist of amplifier circuits,drive motors and lead screws.The MCU feeds the control signals of each axis to the amplifier circuits.The control signals are used to actuate drive motors to position the machine table.

5.Machine tools:

CNC controls are used to control various types of machine tools.It has a slided table and a spindle to control the speed and position.The machine table is controlled in X and Y axes, while the spindle runs along Z axis.

6.Feedback system:

The feedback system is also referred to as measuring system.It uses position and speed transducers to continuosly monitor the position at which the cutting tool is located at any particular instant.The MCU uses the difference between the reference signals and feedback signals to generate control signals for correcting position and speed errors.

Basic concept of robotics:

Robotics is the science and technology of designing, making, and applying robots, including theory from many contributing fields. A robot is a mechanical or virtual,artificial agent. It is usually an electromechanical system, which, by its appearance or movements, conveys a sense that it has intent or agency of its own.

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