February 7, 2022

NC vs CNC | Key Differences and Similarities

What is NC Programming?

NC programming is a traditional system implemented in various machining tools and industries. It uses pre-recorded information in the machining process. It specifies the control of the machine movements and different tasks. The support of instructions is represented as a sequence of numbers. It also uses fixed logical functions to handle a machine tool.

Electronic systems drive NC, and you cannot alter the functions in NC because it isn’t programmable. The reason is because of the rigid wiring of the control logic, causing it to be hardwired.

An external medium such as paper tape or magnetic tape is used to feed the instructions into the NC machines. It takes a step-by-step approach to read the information from the tape, which it keeps in the memory of the control system known as buffer storage.

What is CNC Programming?

CNC programming has machines that store programs and rational functions in computer chips. These are soft-wired. CNC comes from merging the computer and the Numerical control. It utilizes internal computers comprising memory registers. They store different routines that can successfully manipulate logical functions.

CNC vs. NC

CNC refers to Computer Numerical Control, and NC stands for Numerical Control. CNC and NC differ in names and vary in the user interface. In NC, the input given is by magnetic tapes or punched cards. The interface in CNC is through the computer; any changes to the program can be done immediately by editing it In the spot, which is more convenient.

  • NC machines receive instructions through punched cards. CNC makes use of the computer to input instructions.
  • You can only modify NC programs by changing the information in the punched cards, while you can only change CNC directly from the computer.
  • You cannot alter operational parameters in NC machines, yet it is easier to adjust parameters in CNC machines.
  • CNC machines can use computer chips for memory storage, while NC has no mechanism to store information other than punched cards.
  • NC machines are cheaper than CNC machines, which require more maintenance.
  • CNC machines have high accuracy and are flexible compared to NC controls
  • You require more time and expertise to execute a job when you use NC machines; CNC machines are fast and automated, needing less manual work.
  • You can run a CNC machine continuously for 24 hours, while it’s impossible to run an NC machine continuously.

Advantages of CNC machines

  • CNC machines require fewer operators because they need minimum supervision.
  • They take less time to execute a job and are highly accurate.
  • You can make complex designs with CNC machines without the possibility of human error.
  • There’s much safety in using CNC machines because they usually operate behind a guard or a closed transparent safety door.
  • There’s a reduction in energy consumption when using CNC machines.

Advantages of NC machines

  • NC machines are less costly.
  • They require less maintenance.
  • NC machines understand numbers and symbols.

Pros and Cons of CNC machines


  • You can run CNC machines for 24 hours without shutting them down and only switch them off during a maintenance process.
  • They offer product consistency. You can produce the same high-quality products time after time without flaws.
  • Using CNC machining requires less staff which reduces labor costs and human errors.
  • CNC machining uses software that you can upgrade to improve the machine.
  • High technology use in CNC machines allows you to create complex designs that are impossible with manual machines.
  • CNC machines require minimum supervision, meaning one person can manage many programmed machines
  • Less expertise is needed to operate CNC machines.


  • It is very costly to maintain CNC machining, and the machines are expensive.
  • CNC machining can lead to unemployment because it requires less staff to operate.
  • CNC machining requires continuous maintenance.

Difference between NC and CNC press brake

  • In RAM Synchronisation, the CNC press brake offers stable synchronous performance. It provides better flexibility. The CNC controller can detect and correct RAM inclination.
  • The torsion rod in the NC press brake makes the RAM synchronize mechanically.
  • The CBC press brake system can identify the position of each back gauge axis automatically according to the bending height.
  • The back gauge can only move back and front in the NC press brake by manually inputting the value.
  • There’s easy program modification and editing, date or graph programming in the CNC press brake.
  • There’s program cylinder stroke back gauge movement in the NC press brake.
  • You can find several axes in the CNC press brake; NC has only X-axis, front and back.
  • The bending angle accuracy in the CNC press brake is less or equal to 18′. In NC, it is 30′ Or less.
  • The RAM down the speed in the CNC press brake is 160-180 mm/s. In NC press brake, it is 80-100 mm/s

CNC machines full form

  • Central processing unit
  • Input devices
  • Machine Control Panel
  • Programmable logic controller
  • Servo control unit
  • Display unit

NC full form

  • Program of instructions

The program of instructions is a step-by-step set of instructions that informs the machine tool what to do. An input medium programs it in numeric or symbolic form that the controller unit interprets. The input medium is the punched cards and magnetic tape. Two methods exist to input data into the NC stem; the manual system or using direct links with the computer. Typical for NC machines, the manual method allows only one entry of instructions that you cannot alter.

  • Machine controller unit

The control unit controls the passage of equipment, tool changes, and other functions. The machine controller comes with electronics and hardware. They read and interpret the program of instructions. It then converts the instructions into mechanical processes of machine tools.

  • Machine tool

The machine tool is the third primary component of an NC system. It performs valuable functions.

Servo motors

  • Feedback unit

The feedback unit is the position feedback package. Its purpose is to feed the information of the actual position of all the movements to the control unit. The control unit will compare the natural trends with the required activities.

  • Magnetic box

The magnetic box gets electric signals from the control unit for most activities, except for servo motor drives. Some of the actions directed from the magnetic box are switching on and off spindle motor drives. It also selects spindle speeds, controls the coolant supply, and more.

  • Control panel (manual control)

The control panel consists of the dials and switches the operator uses to run the NC system. It can include data displays to offer information to the operator.

  • Machine tool applications

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