MILLING MACHINES

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• Q1: What is a Milling Machine?
  Ans: A milling machine is a machine tool used to remove material from a workpiece by using a rotating cutting tool. It is mainly used for shaping and cutting solid materials like metal.
• Q2: Write any four uses of the Milling Machine.
  Ans: The uses of a milling machine are as follows:

  • ➔ Cutting and shaping metal surfaces
  • ➔ Making slots and grooves
  • ➔ Producing gears and threads
  • ➔ Drilling and boring operations
• Q3: What is the working principle of a Milling Machine?
  Ans: The working principle of a milling machine is based on the rotation of a cutting tool.
  The cutter rotates at high speed and removes material from the stationary or moving workpiece.
• Q4: Briefly discuss the working of a Milling Machine.
  Ans: In a milling machine, the workpiece is fixed on the table.
  A rotating cutter removes unwanted material from the workpiece.
  The table can move in different directions to get the required shape and size.
• Q5: Name the types of Milling Machines.
  Ans: The types of milling machines are:

  • ➔ Vertical Milling Machine
  • ➔ Horizontal Milling Machine
  • ➔ Universal Milling Machine
  • ➔ Planner Milling Machine
  • ➔ Bed Type Milling Machine
  • ➔ Duplicating Milling Machine
  • ➔ Duplex Milling Machine
  • ➔ Column and Knee Type Milling Machine
• Q6: Briefly explain Vertical Milling Machine.
  Ans: In a vertical milling machine, the spindle is placed vertically.
  The cutting tool rotates in a vertical direction.
  It is mainly used for face milling and end milling operations.
• Q7: Briefly explain Horizontal Milling Machine.
  Ans: In a horizontal milling machine, the spindle is placed horizontally.
  The cutter rotates in a horizontal direction.
  It is used for heavy cutting and large workpieces.
• Q8: Briefly explain Universal Milling Machine.
  Ans: A universal milling machine can perform multiple operations.
  Its table can be swiveled to different angles.
  It is used for complex and angular machining work.
• Q9: Briefly explain Planner Milling Machine.
  Ans: A planner milling machine is used for machining large surfaces.
  The workpiece moves while the cutter remains stationary.
  It is suitable for heavy and large jobs.
• Q10: Briefly explain Bed Type Milling Machine.
  Ans: In a bed type milling machine, the table is fixed on the bed.
  The spindle moves vertically to perform cutting.
  It is used for heavy-duty operations.
• Q11: Briefly explain Duplicating Milling Machine.
  Ans: A duplicating milling machine is used to copy the shape of a model.
  It follows a template to produce identical parts.
  It is commonly used in mass production.
• Q12: Briefly explain Duplex Milling Machine.
  Ans: A duplex milling machine has two spindles.
  It can machine two surfaces at the same time.
  It increases productivity and saves time.
• Q13: Briefly explain Column and Knee Type Milling Machine.
  Ans: This type of machine has a vertical column and an adjustable knee.
  The knee supports the table and can move up and down.
  It is widely used in workshops for general machining.
• Q14: What is a Pantograph?
  Ans: A pantograph is a mechanical device used to copy or reproduce a design at a different scale, either larger or smaller.
• Q15: Briefly explain the working of a Pantograph.
  Ans: A pantograph works by tracing a design with a pointer.
  The movement is transferred through linked arms.
  It produces a scaled copy of the original design.
• Q16: Define Slab Milling.
  Ans: Slab milling is a machining process in which a flat surface is produced by using a rotating cutter with teeth on its periphery.
• Q17: Define Gang Milling.
  Ans: Gang milling is a process in which multiple cutters are used together on one arbor to perform different operations at the same time.
• Q18: State the driving mechanism of Milling Machine
  Ans: The driving mechanism of a milling machine includes:

  • ➔ Electric motor
  • ➔ Belt and pulley system
  • ➔ Gear mechanism
• Q19: Name the parts of a Milling Machine.
  Ans: The main parts of a milling machine are:

  • ➔ Base
  • ➔ Column
  • ➔ Knee
  • ➔ Table
  • ➔ Spindle
  • ➔ Arbor
  • ➔ Over Arm
  • ➔ Arbor Support
• Q20: What is a Work Piece in a Milling Machine?
  Ans: A workpiece is the material or object that is fixed on the machine table and is being cut or shaped during the milling operation.
• Q21: What is a Base in a Milling Machine?
  Ans: The base is the bottom part of the milling machine. It supports the entire machine and provides stability.
• Q22: What is a Column in a Milling Machine?
  Ans: The column is a vertical structure mounted on the base. It supports the spindle and other parts of the machine.
• Q23: What is an Over Arm in a Milling Machine?
  Ans: The over arm is a horizontal bar that supports the arbor. It provides rigidity and stability during machining.
• Q24: What is an Arbor Support in a Milling Machine?
  Ans: Arbor support is a part that holds and supports the outer end of the arbor. It helps reduce vibration during cutting.
• Q25: What is a Knee in a Milling Machine?
  Ans: The knee is a movable part that supports the table. It can move up and down to adjust the position of the workpiece.
• Q26: What is a Spindle in a Milling Machine?
  Ans: The spindle is a rotating part of the milling machine that holds and drives the cutting tool. It provides motion to the cutter.
• Q27: What is a Saddle in a Milling Machine?
  Ans: The saddle is a part mounted on the knee that supports the table. It allows movement of the table in a cross direction.
• Q28: What is Swivelling Table Housing in a Milling Machine?
  Ans: The swivelling table housing allows the table to rotate at different angles. It is used for angular and complex machining operations.
• Q29: State the use of the Work table in Milling Machine.
  Ans: The work table is used to hold and support the workpiece during machining operations. It can move in different directions to position the workpiece properly.
• Q30: What is a Vertical Feed Crank in a Milling Machine?
  Ans: The vertical feed crank is used to move the knee or table up and down. It helps in adjusting the vertical position of the workpiece.
• Q31: What is a Table Hand Wheel in a Milling Machine?
  Ans: The table hand wheel is used to move the table in the longitudinal direction (left and right).
• Q32: What is a Cross Hand Wheel in a Milling Machine?
  Ans: The cross hand wheel is used to move the table in the cross direction (in and out).
• Q33: What is a Coolant Pump in a Milling Machine?
  Ans: A coolant pump supplies coolant fluid to the cutting area. It helps in cooling, lubrication, and removing chips.
• Q34: Which coolant is used in a Milling Machine?
  Ans: The commonly used coolants are:

  • ➔ Water-soluble oil
  • ➔ Cutting oil
  • ➔ Synthetic coolant
• Q35: What is a Belt Drive in a Milling Machine?
  Ans: A belt drive is a mechanism that transmits power from the motor to the spindle using belts and pulleys.
• Q36: What is a Feed Change Gear Box in a Milling Machine?
  Ans: The feed change gear box is used to control and change the speed of feed movement of the table.
• Q37: What are Longitudinal Feed Trip Dogs in a Milling Machine?
  Ans: These are devices used to automatically stop or reverse the table movement in the longitudinal direction.
• Q38: What are Vertical Feed Trip Dogs in a Milling Machine?
  Ans: These are used to control and stop the vertical movement of the table or knee automatically.
• Q39: What are Cross- Feed Trip Dogs in a Milling Machine?
  Ans: These are used to control and stop the cross movement of the table automatically.
• Q40: What are Wiper Pads in a Milling Machine?
  Ans: Wiper pads are used to clean dirt, chips, and dust from machine guideways. They help in smooth movement and reduce wear.
• Q41: What is the function of the Main Drive Box in a Milling Machine?
  Ans: The main drive box controls the speed and power of the spindle. It helps in selecting different cutting speeds.
• Q42: What are Trip Dogs in a Milling Machine?
  Ans: Trip dogs are adjustable stops that control the automatic movement of the table. They help in stopping or reversing motion.
• Q43: Briefly discuss the care and maintenance of a Milling Machine?
  Ans: Care and maintenance include:
  

  • ➔ Regular cleaning of machine parts
  • ➔ Proper lubrication of moving parts
  • ➔ Checking alignment and adjustments
  • ➔ Avoiding overloading
  • ➔ Keeping the machine dry and rust-free
• Q44: What is a Gib?
  Ans: A gib is a thin strip used to adjust and control the clearance between sliding parts of the machine.
• Q45: What is Gib Adjustment?
  Ans: Gib adjustment is the process of tightening or loosening the gib to remove play and ensure smooth movement.
• Q46: What is Table Gib Adjustment?
  Ans: Table gib adjustment is done to remove looseness in the table movement and ensure smooth sliding.
• Q47: What is Saddle Gib Adjustment?
  Ans: Saddle gib adjustment is used to control the movement of the saddle and remove any unwanted play.
• Q48: What is Knee Gib Adjustment?
  Ans: Knee gib adjustment is done to ensure proper vertical movement of the knee without looseness.
• Q49: State at least six safety precautions while operating a Milling Machine.
  Ans: The safety precautions are:

  • ➔ Wear proper safety equipment
  • ➔ Do not wear loose clothes
  • ➔ Keep hands away from rotating cutter
  • ➔ Secure the workpiece properly
  • ➔ Stop the machine before adjustments
  • ➔ Keep the work area clean
• Q50: State the dress code in a workshop while operating the Milling Machine.
  Ans: The dress code includes:

  • ➔ Wear fitted clothes
  • ➔ Use safety shoes
  • ➔ Wear goggles
  • ➔ Avoid jewelry and loose items
• Q51: Write the importance of Work Station Light while working with a Milling Machine.
  Ans: Work station light is important because:
  

  • ➔ It improves visibility
  • ➔ Helps in accurate machining
  • ➔ Reduces chances of errors
  • ➔ Increases safety
• Q52: State any four House Keeping precautions regarding Milling Machines.
  Ans: The housekeeping precautions are:

  • ➔ Keep the floor clean and dry
  • ➔ Remove chips regularly
  • ➔ Arrange tools properly
  • ➔ Maintain cleanliness around the machine