Unit 3: Drilling Operations

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Sections

Quick Formula Reference
Cutting Speed
V = πDN / 1000
Material Removal Rate
MRR = (πD²fN) / 4
Drilling Time
T = L / (f × N)
Practice Problems
50+ ProblemsDrilling Operations
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Drilling Machines

Section 1 of 7

3D Drilling Machine Visualization

Explore different drilling machines in interactive 3D. Watch the drilling process with rotating bits and chip formation.

Upright Drilling Machine
Click play to start drilling

Portable Drilling

Light weight
Compact
Up to 18mm holes

Sensitive Drilling

Hand feed control
High speed
Up to 15mm holes

Upright Drilling

Floor mounted
Power feed
Medium capacity

Radial Drilling

Swinging arm
Large workpieces
High flexibility

Real-World Applications

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PCB Manufacturing
Circuit board holes
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Furniture Making
Assembly holes
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Construction
Anchor holes
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Automotive
Engine components
Drilling Operations - Complete Study Guide

Drilling Theory & Mechanics

Cutting Action in Drilling:
  • • Primary cutting: Main cutting edges remove material
  • • Secondary cutting: Chisel edge crushes material
  • • Chip formation: Continuous, discontinuous, segmented
  • • Cutting forces: Thrust force, torque, radial forces
Drill Geometry Parameters:
  • • Point Angle: 118° standard, 135° for hard materials
  • • Helix Angle: 30° standard, affects chip removal
  • • Relief Angle: 8-12°, prevents rubbing
  • • Web Thickness: 0.1-0.2D, affects rigidity

Drilling Calculations & Formulas

Cutting Speed: V = πDN/1000 (m/min)
Feed Rate: f = mm/rev per cutting edge
Material Removal Rate: MRR = πD²f N/4 (mm³/min)
Drilling Time: T = L/(f×N) (min)
Power Required: P = (MRR × Specific Energy)/60 (kW)

Solved Exam Problems

Problem 1: Calculate drilling time for 50mm deep hole, 10mm diameter, feed=0.2mm/rev, speed=1000rpm
Solution: T = 50/(0.2×1000) = 0.25 min = 15 seconds
Problem 2: Find cutting speed for 8mm drill at 1500rpm
Solution: V = π×8×1500/1000 = 37.7 m/min
Section Summary
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Key Concept
Drilling Machines
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Industry Application
Precision Manufacturing
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Learning Outcome
Machine Operations