Machining

Machining Strengths: Material diversity, Geometric complexity, accuracy

Advantages of Machining: Adaptability, Automation potential

Disadvantages of Machining: Material waste Time, Tool wear, Heat, Environmental impact

Role of Machining: Creates final shape, Dimensional finish, Specific geometry

Machining Limitations: Thin or fragile materials, High production volume, Large workpieces

Main Machining Operations:

Turning:

  • Great for cylindrical shapes with high precision; rotating piece meets stationary cutting tool

Turning Types:

  • Straight turning (along the length)

  • Facing (flat surface)

  • Chamfering

  • Grooving

  • Threading

Drilling:

Creates cylindrical holes using a rotating drill bit (screw holes, fluid passages)

Drilling Types:

  • Drilling (long holes)

  • Counterboring (bigger at surface)

  • Countersinking (cone shape)

  • Tapping (threads)

  • Reaming (improves hole accuracy)

Milling:

  • Rotating cutter removes material from a fixed piece (flat surfaces, angled surfaces, pockets)

Milling Types:

  • Face milling

  • End milling (for pockets)

  • Slot milling (for stairs)

  • Pocketing

Other Machining Operations:

  • Planing: Similar to milling, uses linear motion for large flat workpieces

  • Broaching: Used for creating holes or grooves in tubes

  • Sawing: Used for cutting materials

Chips:

Factors Affecting Chip Formation:

  • Material properties

  • Cutting tool geometry

  • Cutting parameters

  • Lubricant

Continuous Chips:

  • Fragments with irregular shapes, associated with brittle materials, caused by fractures due to high stress

  • Impact: Can jam and damage tools, create rough surfaces, increase tool wear

Continuous Chips (Unbroken Spirals):

  • Long, unbroken spirals, common in ductile materials, caused by deformation due to lower stress

  • Impact: Easier to control, better surface finish, higher tool wear

Continuous chips With Built Up Edge (blue)

  • Continuous chip with deposited material on tool face, mainly soft ductile mats, built up from friction and heat causing it to weld onto tool face

  • Impact: Jamming and poor surface finish, accelerates tool wear, wrong dimensions


  • Serrated Chips:

    • Description: serrated, tough material, high to low shear

    • Impact: difficult to control, wavy surface finish, eye cutting Force increased wear

Lubricant In Machining

  • Purpose: reduces chip formation, coefficient of friction, energy, cutting temperature