14 Difference Between NC And CNC Machine (With Comparison Chart)

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Numerical Control (NC) Machine

Numerical control, commonly referred to as NC, is a machine which is controlled by the set of instructions in the form of numbers, letters and symbols. In this case, the set of instruction is referred to as program.

NC is essential to the operation of modern industrial robots. The two basic types of NC systems are point-to-point in which a device is programmed to perform a series of motions with fixed starting and stopping points. The other type is the continuous-path in which a point-to-point programmed device has sufficient memory to be ‘’aware’’ of its former actions and their results and to act in accordance with this information. 

Numerical control (NC) machines are used in manufacturing tasks such as milling, turning, punching and drilling. It also offers less accuracy and fewer computing power than Computer Numerical Control and also take more time to execute a job.

Many applications of numerical control have been developed since its initial use to control machine tools. Other machines using numerical control include:

  • Component-insertion machines (used in electronics assembly, drafting engineering drawings)
  • Coordinate measuring machines (that perform accurate inspection of parts)
  • Flaming cutting machine.

In the above named machines, the term numerical control is typically not always used, but the operating principle is the same (coded numerical data are employed to control the position of a tool or workhead relative to some object.

It is important to note that, NC is not a machining method rather; it is a concept of machine control.  Although the most popular applications of NC are in machining, NC can be applied to many other operations, including welding, sheet metalworking, riveting etc.

What You Need To Know About NC Machine

  1. NC is a machine which is controlled by the set of instructions in the form of numbers, letters and symbols. In this case, the set of instruction is referred to as program.
  2. NC is hardware based type system.
  3. In the NC machine, the programs are fed into the media tapes/ punch cards.
  4. The operation of an NC machine requires a highly skilled operator.
  5. NC machine works on the X-Y and straight-line axis.
  6. The NC machine requires more time for the execution of the task
  7. In the NC machine, programs cannot be stored in the NC machine.
  8. It is not possible to run NC machine continuously.
  9. The accuracy of NC machine is less when compared to that of CNC machine.
  10. In the NC machine, the modification in the program is difficult.
  11. The cost of NC machine is comparatively less to that of CNC machine.
  12. NC machine provides less flexibility and computational capability.
  13. Maintenance cost of NC machine is less when compared to that of CNC machine.
  14. In the NC machine, the operation parameter cannot be changed once indexed.

What Is Computer Numerical Control (CNC) Machine?

Computer numerical control, popularly referred to as CNC is a method for automating control of machine tools through the use of software embedded in a microcomputer attached to the tool. A CNC machine can process a piece of material to meet specifications by following a coded programmed instruction and without a manual operator. This process is suitable for a wide range of materials including metals, plastics, wood, glass, foam and composites and finds application in a variety of industries such as large CNC machining and CNC machining aerospace parts.

Instructions are delivered to a CNC machine in the form of a sequential program of machine control instructions such as G-code and then executed. The program can be written by a person or far more often generated by graphical computer-aided design (CAD).

CNC Machine

The automated nature of CNC machining enables the production of high precision and high accuracy, simple parts and the cost-effectiveness when fulfilling one-off and medium-volume production runs. The basic CNC machining process includes the following stages:

  • Designing the CAD model
  • Converting  the CAD file to a CNC program
  • Preparing the CNC machine
  • Executing the machining operation

Examples of CNC Machines Include:

  • Lathe
  • Mill
  • Plasma cutter
  • Electric discharge machining
  • Multi-spindle machine
  • Wire EDM
  • Sinker EDM
  • Water jet cutter

What You Need To Know About CNC Machine

  1. CNC is a machine which is used to control the motions of the workpiece and tool with the help of prepared program in computer. The program is written in alphanumeric data.
  2. CNC is software based system.
  3. In CNC machine, the programs are fed directly into the computer by a small keyboard similar to our traditional keyboard.
  4. A semiskilled operator can run the CNC machine. The main requirement is that the operator must basic knowledge of computer system.
  5. CNC machine works on the X-Y-Z axis.
  6. The CNC machine takes very less time in the execution of the task.
  7. In the CNC machine, programs can be stored in computer and used repeatedly.
  8. NC machine can be run for throughout the day (24 hours).
  9. The products developed by CNC machines are high-quality products with high precision and accuracy rate.
  10. In the CNC machine, the modification in the program is very easy.
  11. The cost CNC machine is comparatively high to that of NC machine.
  12. NC machine provides additional flexibility and computational capability.
  13. Maintenance cost of CNC machine is comparatively high to that of NC machine.
  14. In the CNC machine, the operation parameter can be changed easily.

Difference Between NC And CNC Machine In Tabular Form

BASIS OF COMPARISON NC MACHINE CNC MACHINE
Description NC is a machine which is controlled by the set of instructions in the form of numbers, letters and symbols. CNC is a machine which is used to control the motions of the workpiece and tool with the help of prepared program in computer.  
 Nature NC is hardware based type system.   CNC is software based system.  
Programs The programs are fed into the media tapes/ punch cards.   The programs are fed directly into the computer by a small keyboard similar to our traditional keyboard.  
Skill The operation of an NC machine requires a highly skilled operator.   A semiskilled operator can run the CNC machine. The main requirement is that the operator must basic knowledge of computer system.  
Working It works on the X-Y and straight-line axis.   It works on the X-Y-Z axis.  
Execution Time It requires more time for the execution of the task.   It takes very less time in the execution of the task.  
Storage Of Programs Programs cannot be stored in the NC machine.   Programs can be stored in computer and used repeatedly.  
Operation It is not possible to run NC machine continuously.   It can be run for throughout the day (24 hours).  
Accuracy The accuracy of NC machine is less when compared to that of CNC machine.   The products developed by CNC machines are high-quality products with high precision and accuracy rate.  
Modification The modification in the program is difficult.   The modification in the program is very easy.  
Cost The cost of NC machine is comparatively less to that of CNC machine.   The cost CNC machine is comparatively high to that of NC machine.  
Flexibility NC machine provides less flexibility and computational capability.   NC machine provides additional flexibility and computational capability.  
Maintenance Maintenance cost of NC machine is less when compared to that of CNC machine.   Maintenance cost of CNC machine is comparatively high to that of NC machine.  
Operation Parameter The operation parameter cannot be changed once indexed.   The operation parameter can be changed easily.