Recent

  • Show all results for ""

🎧 New: AI-Generated Podcasts Turn your study notes into engaging audio conversations. Learn more

Unit 4: Standard of Measurements
40 Questions
0 Views

Unit 4: Standard of Measurements

Created by
@SprightlyVision

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary limitation of measurements made using traditional methods?

  • Inability to measure complex shapes
  • Lack of precision in measuring instruments
  • Inability to measure small dimensions
  • Dependency on the skill of the operator and being time-consuming (correct)

    • What is the primary cause of characteristic variability in a manufacturing process?

  • Lack of training among operators
  • Improperly adjusted machines, operator error, tool wear, and/or defective raw materials (correct)
  • Random fluctuations in the production process
  • Natural variability in materials

    • What is the purpose of controlling a manufacturing process?

  • To achieve consistent production and meet design requirements (correct)
  • To reduce production costs
  • To improve product quality
  • To increase production volume

    • What is the term used to describe the permissible level of variation in dimension during manufacture?

    <p>Tolerance</p> Signup and view all the answers

    What is the basic or nominal size of a component?

    <p>The size based on which the dimensional deviations are given</p> Signup and view all the answers

    What is the difference between the upper and lower limits of a component's dimension?

    <p>Permissive tolerance</p> Signup and view all the answers

    What is the primary reason why a rule is not suitable for measuring the distance between two edges?

    <p>Because it is a line-measuring device</p> Signup and view all the answers

    What is the main advantage of using end standards over line standards?

    <p>They provide higher accuracy of measurement</p> Signup and view all the answers

    What is the primary cause of undersizing when using line standards?

    <p>Wear on the leading ends of the scale</p> Signup and view all the answers

    What is the minimum dimensional tolerance that can be obtained using end standards?

    <p>±0.0005 mm</p> Signup and view all the answers

    What is the primary reason why a magnifying lens or microscope is required for high-accuracy measurement using line standards?

    <p>To magnify the scale markings</p> Signup and view all the answers

    What is the primary reason why end standards are not subjected to parallax errors?

    <p>Because they rely on the feel of the operator</p> Signup and view all the answers

    What is the primary reason for providing clearance between a shaft and a hole?

    <p>To allow for an oil film to be maintained for lubrication purposes</p> Signup and view all the answers

    What is the consequence of manufacturing parts to exact sizes without considering variations?

    <p>Increased production cost and reduced quality</p> Signup and view all the answers

    What is the principle behind interchangeable manufacture?

    <p>Manufacturing components in bulk to the desired accuracy</p> Signup and view all the answers

    What is the benefit of interchangeable assembly?

    <p>Increased productivity and reduced manufacturing cost</p> Signup and view all the answers

    What is the distribution of dimensions produced in a controlled manufacturing process?

    <p>Normal or Gaussian distribution</p> Signup and view all the answers

    What is the consequence of not considering dimensional variations in manufacturing?

    <p>Reduced product quality and increased cost</p> Signup and view all the answers

    What is the primary purpose of interchangeable manufacture?

    <p>To reduce manufacturing and assembly time and enhance quality</p> Signup and view all the answers

    What is the main reason for providing tolerances in manufacturing?

    <p>To permit dimensional variations in the manufacture of components</p> Signup and view all the answers

    What is universal interchangeability?

    <p>When parts manufactured at different locations are randomly chosen for assembly</p> Signup and view all the answers

    What is the primary advantage of interchangeable assembly?

    <p>Ease of replacement of defective or worn-out parts</p> Signup and view all the answers

    What is the significance of traceability to international standards in universal interchangeability?

    <p>To ensure common standards are followed by all</p> Signup and view all the answers

    What is the definition of tolerance?

    <p>The magnitude of permissible variation of a dimension or other measured value or control criterion from the specified value</p> Signup and view all the answers

    What is the main reason why scientists opted for a natural unit for length?

    <p>To eliminate the effect of environmental conditions on the unit of length</p> Signup and view all the answers

    Which type of standard is defined as the distance between two flat parallel surfaces?

    <p>End standard</p> Signup and view all the answers

    What is the significance of the wavelength of monochromatic light in the measurement of length?

    <p>It remains constant under different environmental conditions</p> Signup and view all the answers

    Why are material standards no longer used as the fundamental unit of linear measurement?

    <p>They can change their size with temperature and other conditions</p> Signup and view all the answers

    What is the difference between a line standard and an end standard?

    <p>A line standard is used to measure distances between lines, while an end standard is used to measure distances between surfaces</p> Signup and view all the answers

    What is the significance of the Act of Parliament in relation to the unit of linear measurement?

    <p>It governed the use of yard and metre as legal line standards</p> Signup and view all the answers

    What is the primary factor that determines the specification of tolerance limits?

    <p>Functional requirements</p> Signup and view all the answers

    What is the difference between the upper and lower limits of a component?

    <p>Tolerance</p> Signup and view all the answers

    What type of fit is used where a permanent or semi-permanent assembly is required?

    <p>Interference fit</p> Signup and view all the answers

    What is the purpose of the ISO system of limits and fits?

    <p>To define the relationship between mating parts</p> Signup and view all the answers

    What is the purpose of a Go gauge?

    <p>To check the lower limit of a part</p> Signup and view all the answers

    What type of gauge is used to check the dimensions of shafts?

    <p>Ring gauge</p> Signup and view all the answers

    What is the purpose of a No-Go plug gauge?

    <p>To check the upper limit of a hole</p> Signup and view all the answers

    What is the primary purpose of gauges in manufacturing?

    <p>To ensure parts fit and function correctly</p> Signup and view all the answers

    What is the primary difference between the Hole Basis System and the Shaft Basis System?

    <p>The basic size of the part</p> Signup and view all the answers

    What is the purpose of limits in manufacturing?

    <p>To ensure parts fit and function correctly</p> Signup and view all the answers

    Study Notes

    Standard of Measurements

    • Two standard systems for linear measurement: English (yard) and metric (metre) systems
    • The metric system is widely accepted and used as the fundamental unit of linear measurement
    • Scientists have always sought a suitable unit for length that remains constant regardless of environmental conditions
    • The wavelength of monochromatic light is used as a natural and invariable unit for length

    Line and End Measurements

    • Line standard: measures distance between two engraved lines
      • Examples: yard and metre
      • Used for quick and easy measurements
      • Limited accuracy (±0.2 mm) and requires magnifying lens or microscope for high accuracy
    • End standard: measures distance between two flat and parallel surfaces
      • Examples: slip gauges, end bars, and micrometer anvils
      • Used for precision measurements in workshops and laboratories
      • High accuracy (up to ±0.0005 mm) and requires skill and time for measurement

    Characteristics of Line Standards

    • Quick and easy measurements
    • Limited accuracy (±0.2 mm)
    • Engraved lines have thickness, making high accuracy measurements difficult
    • Markings on the scale are not subjected to wear, but leading ends may wear, resulting in undersizing
    • No built-in datum, making alignment difficult
    • Subject to parallax effect, leading to reading errors

    Characteristics of End Standards

    • High accuracy (up to ±0.0005 mm)
    • Measurements are time-consuming and require skill
    • Measuring surfaces are subjected to wear
    • Built-in datum, making alignment easy
    • Not subject to parallax error

    Comparison between Line and End Standards

    • Line standards: quick and easy, but limited accuracy and no built-in datum
    • End standards: high accuracy, but time-consuming and requires skill, with a built-in datum

    Limits, Fits, and Tolerances

    • Manufacturing processes inherently produce variations in size and shape
    • Tolerances: the magnitude of permissible variation in a dimension or measured value
      • Upper limit: maximum allowable dimension
      • Lower limit: minimum allowable dimension
      • Tolerance: difference between upper and lower limits
    • Fits: describe the relationship between mating parts, such as a hole and a shaft
      • Clearance fit: gap between mating parts, used for easy assembly and disassembly
      • Interference fit: overlap between mating parts, used for permanent or semi-permanent assembly
      • Transition fit: slight gap or overlap, used for accurate location and moderate tightness

    Principle of Interchangeability

    • Manufacture of identical parts in bulk, allowing for interchangeable assembly
    • Essential for mass production and modern manufacturing techniques
    • Enables the production of components with a desired fit, without further modification during assembly
    • Increases productivity, reduces manufacturing cost, and facilitates ease of replacement

    Tolerances

    • Essential for manufacturing products with a desired level of accuracy and quality
    • Tolerance principles: permit dimensional variations, achieve interchangeable assembly, and ensure functional requirements
    • Tolerance is an absolute value, defined as the algebraic difference between the upper and lower acceptable dimensions
    • Industry follows approved accuracy standards, such as ANSI and ASME, to manufacture different parts### Tolerances
    • A letter indicates the fundamental deviation (position of tolerance zone relative to nominal size)
    • A number indicates the tolerance grade (size of tolerance zone)

    Basis Systems

    • Hole Basis System: hole is kept as basic size, shaft size is varied to get desired fit
    • Shaft Basis System: shaft is kept as basic size, hole size is varied to get desired fit

    Gauges

    • Essential for quality control in manufacturing processes
    • Used to measure dimensions of manufactured parts and ensure conformity to specified limits

    Types of Gauges

    • Limit Gauges:
      • Check whether part's dimension falls within specified limits
      • Go Gauge: checks lower limit, part should fit into or pass through
      • No-Go Gauge: checks upper limit, part should not fit into or pass through

    Plug Gauges

    • Cylindrical gauges used to check dimensions of holes
    • Go Plug Gauge: should fit into hole
    • No-Go Plug Gauge: should not fit into hole

    Ring Gauges

    • Used to check dimensions of shafts
    • Go Ring Gauge: shaft should fit into ring
    • No-Go Ring Gauge: shaft should not fit into ring

    Snap Gauges

    • Used to check external dimensions of cylindrical parts, such as shafts
    • Go Snap Gauge: part should pass through
    • No-Go Snap Gauge: part should not pass through

    Limits and Fits

    • Limits: define permissible variations in dimensions to ensure parts fit and function correctly
    • Fits: describe relationship between mating parts, ensuring correct assembly (clearance, interference, and transition fits)

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    This quiz covers the standard systems for linear measurement, including the English and metric systems, and the importance of the metric system as the fundamental unit of linear measurement.

    More Quizzes Like This

    Unit 4: Standard of Measurements
    40 questions

    Unit 4: Standard of Measurements

    SprightlyVision avatar
    SprightlyVision
    Unit 4: Standard of Measurements
    40 questions

    Unit 4: Standard of Measurements

    SprightlyVision avatar
    SprightlyVision
    Metric System Fundamentals
    19 questions

    Metric System Fundamentals

    RadiantLaplace9461 avatar
    RadiantLaplace9461
    Metric System Flashcards
    13 questions

    Metric System Flashcards

    SharperEducation9982 avatar
    SharperEducation9982
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser