Gear Measurement and Inspection

Gear Measurement

• Importance of paying attention to raw material, production cycle, machining, heat treatment, cutting, and surface finish of teeth for proper gear inspection
• Key dimensional accuracy checks: face width, bore, hub, length, and outside diameter
• Eccentricity and concentricity of blanks are crucial, and side faces should be true to the bore
• Additional measurements for precise gears: tip radius, shape of root, and surface finish

Good Alignment of Each Tooth

• Importance of even load distribution over the face of the gear
• Poor tooth alignment can lead to high bearing stresses and concentrated load on one edge
• Checking tooth alignment using a standard roller and surface plate

Parkinson Gear Tester

• Principle: measuring gear variations using a standard gear on a fixed spindle and the gear to be tested on a sliding carriage
• Movement of the sliding carriage indicates gear irregularities, which can be recorded using a dial indicator or a circular chart
• Used for testing spur gears

Limitations of Parkinson Gear Tester

• Limited to simple gear types (e.g., spur gears) and not suitable for complex gear geometries
• Manual operation may introduce human error
• Limited measurement range and accuracy limitations
• No advanced data recording and analysis capabilities
• Slow and labor-intensive process
• Subject to wear and tear, requiring regular calibration and maintenance
• Cost and maintenance concerns
• Single-purpose device

Autocollimator

• Optical instrument used for measuring small angular differences, changes, or deflections
• Principle: using a collimating lens to project parallel light beams and measure reflected light
• Applications:
  • Measuring straightness and flatness of surfaces
  • Precise angular indexing using polygons
  • Comparative measurements using master angles
  • Assessing squareness and parallelism of components
  • Measuring small linear dimensions

Optical Dividing Head

• Precision tool used for accurately dividing a circle into equal parts
• Components:
  • Base
  • Spindle
  • Index plate
  • Sector arms
  • Optical system
  • Crank or handwheel
• Working principle:
  • Mounting the workpiece
  • Setting the angle using the index plate and sector arms
  • Dividing the circle using the crank or handwheel
  • Verifying the angle using the optical system
• Applications:
  • Gear cutting
  • Spline cutting
  • Tool grinding
  • Rotary table operations
• Advantages:
  • High precision
  • Versatility
  • Repeatability

Tool Makers Microscope

• Highly precise optical instrument used for inspecting and measuring small parts, tools, and components
• Components:
  • Optical system
  • Stage
  • Micrometer head
  • Illumination
  • Focusing mechanism
  • Measurement scales
  • Base
• Working principle:
  • Placing the workpiece on the stage
  • Adjusting the stage using micrometer heads
  • Focusing the optical system
  • Illuminating the workpiece
  • Measuring dimensions using reticles or graduated scales
• Applications:
  • Inspecting small parts
  • Tool and die making
  • Quality control
  • Research and development
  • Micro-machining
• Advantages:
  • High precision
  • Versatility
  • Enhanced visibility
  • Ease of use
  • Durability

Interferometry

• Powerful technique for measuring small displacements, refractive index changes, surface irregularities, and other minute changes
• Basic principles:
  • Interference of light waves
  • Coherent light source
  • Splitting and recombining light
• Types of interferometers:
  • Michelson interferometer
  • Fabry-Pérot interferometer
  • Mach-Zehnder interferometer
  • Sagnac interferometer
• Applications:
  • Metrology
  • Astronomy
  • Fiber optics
  • Material science
  • Biology and medicine
• Advantages:
  • High precision
  • Non-contact measurement
  • Versatility
• Disadvantages:
  • Sensitivity to environmental factors
  • Complex setup
  • Cost

Surface Texture

• Importance of controlling surface texture in modern engineering products
• Influence of surface texture on:
  • Appearance
  • Corrosion resistance
  • Wear resistance
  • Fatigue resistance
  • Lubrication
  • Initial tolerance
  • Load carrying capacity
  • Noise reduction
• Reasons for controlling surface texture:
  • Improving service life
  • Reducing fatigue resistance
  • Reducing initial wear