INTRODUCTION TO NUMERICAL CONTROL

Other Chapters

• Q1: What is a Numerical Control System (NC System)?
  Ans: A Numerical Control System is a manufacturing system in which machine operations are controlled by numerical instructions in the form of codes.
• Q2: What is the NC/CNC Program?
  Ans: An NC/CNC program is a set of coded instructions that tells the machine how to move tools and perform machining operations.
• Q3: Name the types of NC/CNC Programming.
  Ans: The types of NC/CNC programming are as followsare:

  • ➔ Manual Programming
  • ➔ Computer-Assisted Programming
• Q4: Write the types of Programming.
  Ans: The types of programming include:

  • ➔ Absolute Programming
  • ➔ Incremental Programming
• Q5: What are the components of a Numerical Control System?
  Ans: Main components of an NC system are as follows:

  • ➔ Input device
  • ➔ Controller
  • ➔ Machine tool
  • ➔ Feedback system
• Q6: Name the media of data storage.
  Ans: Data storage media are as follows:

  • ➔ Paper tape
  • ➔ Magnetic tape
  • ➔ Disk drives
  • ➔ Computer memory
• Q7: What is the purpose of Tape Reader?
  Ans: A tape reader reads the punched tape and sends the instructions to the controller.
• Q8: What is the purpose of Tape Punch?
  Ans: A tape punch is used to prepare or modify punched tapes by creating holes that represent instructions.
• Q9: What is the purpose of the Controller?
  Ans: The controller interprets program instructions and controls the movement of the machine tool.
• Q10: What is an NC Machine?
  Ans: An NC machine is a machine tool that operates automatically using numerical control instructions.
• Q11: What is MCU (Machine Control Unit)?
  Ans: MCU is the control unit that processes input data and controls machine movements.
• Q12: What is a Computer Numerical Control System (CNC System)?
  Ans: A CNC system is an advanced NC system where a computer is used to control machining operations.
• Q13: What is a Computer Numerical Control Machine (CNC Machine)?
  Ans: A CNC machine is a machine tool controlled by a computer using programmed instructions.
• Q14: Write the working of a CNC Machine.
  Ans: The working of a CNC machine is as follows:

  • ➔ Program is entered into the computer
  • ➔ Controller interprets the program
  • ➔ Motors move the tool/workpiece
  • ➔ Machining operation is performed
• Q15: Write the working of an NC Machine.
  Ans: The working of an NC machine is as follows:

  • ➔ Program is prepared on punched tape
  • ➔ Tape is read by tape reader
  • ➔ Controller sends signals
  • ➔ Machine performs operation
• Q16: Briefly state the history of Numerical Control.
  Ans: Numerical Control was developed in the 1950s to automate machine tools using punched tape systems.
• Q17: Name four advantages of Numerical Control System (NC System)?
  Ans: Some of the advantages of NC system are as follows:

  • ➔ High accuracy
  • ➔ Increased productivity
  • ➔ Reduced human error
  • ➔ Consistent quality
• Q18: Name four disadvantages of Numerical Control System (NC System)?
  Ans: Some of the disadvantages of NC system are as follows:

  • ➔ High initial cost
  • ➔ Complex maintenance
  • ➔ Skilled operators required
  • ➔ Limited flexibility
• Q19: Compare NC Machine and CNC Machine?
  Ans: Comparison between NC and CNC machines is as under:

  • ➔ NC uses punched tape, CNC uses computer memory
  • ➔ CNC is more flexible than NC
  • ➔ CNC allows easy program editing
• Q20: List the operations of a Numerical Control Machine Tool?
  Ans: Operations include:

  • ➔ Turning
  • ➔ Drilling
  • ➔ Milling
  • ➔ Grinding
• Q21: Define Process Planning.
  Ans: Process planning is the systematic determination of manufacturing steps required to produce a part.
• Q22: Define Machining.
  Ans: Machining is a manufacturing process in which material is removed to shape a workpiece.
• Q23: Define Turning in Machine Operation.
  Ans: Turning is a machining operation where material is removed using a rotating workpiece.
• Q24: Define Taper Turning in Machine Operation.
  Ans: Taper turning produces a conical surface by gradually reducing the diameter of the workpiece.
• Q25: Define Contour Turning in Machine Operation.
  Ans: Contour turning produces curved or irregular shapes on a rotating workpiece.
• Q26: Name the factors controlling Turning in Machine Operation.
  Ans: Factors controlling turning are as follows:

  • ➔ Cutting speed
  • ➔ Feed rate
  • ➔ Depth of cut
• Q27: Define Facing in Machine Operation.
  Ans: Facing is the operation of machining the flat surface at the end of a workpiece.
• Q28: Define Drilling in Machine Operation.
  Ans: Drilling is the operation of creating a circular hole using a rotating drill.
• Q29: Define Boring in Machine Operation.
  Ans: Boring enlarges an existing hole to improve accuracy and finish.
• Q30: Define Threading in Machine Operation.
  Ans: Threading is the process of cutting screw threads on a workpiece.
• Q31: Define Milling in Machine Operation.
  Ans: Milling removes material using a rotating multi-point cutting tool.
• Q32: Define Knurling in Machine Operation.
  Ans: Knurling creates a patterned surface for better grip.
• Q33: Define Parting in Machine Operation.
  Ans: Parting is the operation of cutting off a finished part from the workpiece.
• Q34: Define Grinding in Machine Operation.
  Ans: Grinding is a finishing process that uses an abrasive wheel to improve surface finish.
• Q35: Define Hobbing in Machine Operation.
  Ans: Hobbing is a machining process used to cut gear teeth.
• Q36: What is an APT Program?
  Ans: APT (Automatically Programmed Tool) is a high-level programming language used for NC machines.
• Q37: When was the APT Program developed?
  Ans: APT was developed in the late 1950s.
• Q38: What is Program Coding in NC Machine Tool Operation?
  Ans: Program coding is the process of converting machining instructions into numerical codes.
• Q39: What is a Process Sheet?
  Ans: A process sheet is a document that lists machining steps, tools, and parameters.
• Q40: What is Servomechanism?
  Ans: A servomechanism is a control system used to accurately control machine movement.
• Q41: What is an Encoder?
  Ans: An encoder is a feedback device that converts motion into electrical signals.
• Q42: What is a Controller?
  Ans: A controller is a device that manages and controls machine tool operations.
• Q43: What are Micro-computers?
  Ans: Micro-computers are small computers that use a microprocessor as the CPU.
• Q44: When were Micro-computers invented?
  Ans: Micro-computers were invented in the early 1970s.