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Numerical Control, Construction, Advantages and disadvantages.

What Is Numerical Control?

Numerical Control: Numerical Control is the method of controlling the machine tool. controlling of machine tool is done by sending the instructions to the machine and changes the function according to the program designed to it. Numerical control system is one kind of tool to control the machining process by adding the program to computer and supplying to machine directly. In numerical control the programs are stored in the punched tape, by this, it can control the speed, machining process, tool changing, feed rate, stop etc. In these type of control system programmers are in the form of Computer Assisted, or in Programming languages and also with the aid of CAD/CAM.

Construction of Numerical Controller:

  1. Controller.
  2. Instructions.
  3. Machine tool.

1. Controller:

  • Controller is the important component in the Numerical Control System, Controller has to send the instructions to the machine tool to cut the workpiece according to the instructions passed to it. This used to control the total machining process. by the help of control unit, the program installed in it send to the machine tool by the signals this instruction is used to verify and send the feedback about the instruction is it accurate or not to the control unit. after this instruction passes the machine tool used to work according to the signals passed to it.

2. Instructions:

  • Instructions are nothing but, ''a way showing to tool to finish the required work'' Instructions are given by the programmer this is in the form of codes.
  • To store these codes there are punched cards, magnetic tapes etc.. are used. this program is designed for getting required work with accurately.
  • This instruction giving to the tool is done by two methods like one is used to pass instruction directly to the machine tool with the help of
  •  the computer this is called direct numerical control and another one is used to pass the instructions to the control unit this is called manual type.

3. Machine tool:

  • This is used to take instructions from the required source and acts according to the instructions. this used to work any kind of operations according to the instructions. it has a cutting tool, spindle, motors with high speed this is controlled by controls.
  • This can make to rotate at any angle and can work with high efficiency by this time can be saved with automatic tool changing.

Coordinate systems in Numerical Control:

There are dividing according to the work.
1. There are 3 linear and 3 rotational axes for flat and prismatic work in this Two of them in linear axis used to move and the remaining one is at the desired position.
like X and Y used to move on the X-Y plane by keeping the X-work table at the desired position. and the Z axis is used to moves the tool.
2. In the rotational axis there is Four or five-axis in this there are three linear and two rotational axes. this is used for making complex works.

Advantages of Numerical Control:

  • In this we can use continuous machine tool.
  • This is useful to automatic drafting, Assembling etc..
  • Time is reduced at inspections.
  • On this machine we can operate turning, drilling, milling etc..
  • There is no use of jigs and fixtures in it.

Disadvantages Of Numerical Control:

  • Tooling cost is high for this.
  • To operate this skilled persons is required.
  • Equipment cost is high.

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