Introduction to Machining and Cutting Tools

Jul 3, 2024

Lecture Notes: Introduction to Machining and Cutting Tools

Introduction

  • Instructor: Dr. Swadesh Singh
  • Qualification: B.Tech from Aligarh Muslim University (University Topper), PhD
  • Research Projects: DRDO, Aeronautics Research Development Board, Department of Atomic Energy, Department of Science and Technology
  • Lecture structure:
    • Class Times: 8:30 PM - 10 PM (Mon-Fri)
    • Duration: 30 days
    • Languages: Hindi and English
  • Aim: To provide deep fundamentals; additional questions may be necessary

Lecture Content

Single Point Cutting Tool

  • Definition: A tool with one cutting edge; fundamental in material removal processes.
  • Importance: Widely studied but not deeply understood without focus on fundamentals.

Components of Single Point Cutting Tool

  • Tool Post: Where the tool is mounted.
  • Main Angles: Rake, clearance, and cutting angles.
    • Clearance Angles: Angle between the tool's leading edge and the workpiece surface.
    • Rake Angles: Determines the direction of chip flow.
    • Cutting Edges: Defined areas where material removal occurs.
  • Elevation and Plan Views: Essential for understanding the orientation.

Tool Movements

  • Carriage Movement: Provides the feed in the machine tool.
  • Cross Slide Movement: Allows adjustment of the tool position.
  • Rotating Workpiece: Key in understanding chip removal dynamics.

Tool Dynamics

  • Chip Formation: Chips flow over the rake surface during cutting.
  • Contact Length: The area over which the tool and chip are in contact.
  • Heat Generation: Due to crystal structure breaking, leading to high temperatures in the cutting area.

Angles in Cutting Tools

  • Primary Angles: Directly affect chip formation and removal efficiency.
  • Secondary Functions: Includes factors like heat dissipation, and tool strength.
  • Coefficient of Friction: Affects tool wear and energy consumption.
    • Friction Models: Stick-slip behavior observed at different cutting conditions.

Rake Angle

  • Primary Objective: Reduce cutting forces by allowing smoother chip flow.
    • Contact Area: Reduced contact area decreases friction and cutting forces.
  • Secondary Objective: Enhance tool life and machining efficiency.
  • Balance: Increasing rake angle reduces cutting force but weakens the tool edge.
  • Optimal Angles: Determined by the workpiece material properties.
    • Soft Materials: Higher rake angles (e.g., aluminum).
    • Hard Materials: Lower or negative rake angles (e.g., cast iron).
    • Tool Material: Different materials may require adjustments in rake angles for optimal performance.

Practical Tips

  • Visualization: Importance of understanding both theoretical and practical aspects through diagrams and animations (limited in live sessions).
  • Participation: Encouraged for deeper understanding and clarification of concepts.
  • Utilizing Resources: Joining the Telegram channel for additional doubts and participating in weekend Zoom sessions for extended learning.

Conclusion

  • Summary: Drill down into fundamentals of single-point cutting tools, heat generation, chip formation, and the importance of rake angles.
  • Next Steps: Continue to follow and participate in the course, and use extended resources for any additional help.

Note: Be consistent and actively participate for a profound understanding of the subject matter.