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Questions and Answers
Which of the following chapters primarily focuses on the layout of tools for automated machines?
Which of the following chapters primarily focuses on the layout of tools for automated machines?
In which chapter can you find information about the design of limit gauges?
In which chapter can you find information about the design of limit gauges?
What type of machinery is discussed in Chapter 7?
What type of machinery is discussed in Chapter 7?
Which chapter explores the concept of tolerances and fits in manufacturing?
Which chapter explores the concept of tolerances and fits in manufacturing?
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According to the content, which chapter provides information on problems related to turret lathes?
According to the content, which chapter provides information on problems related to turret lathes?
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Which chapter deals with the process of setting up both automatic and semi-automatic machines?
Which chapter deals with the process of setting up both automatic and semi-automatic machines?
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Which chapter specifically discusses the design and manufacture of limit gauges?
Which chapter specifically discusses the design and manufacture of limit gauges?
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Which chapters include a section dedicated to problems related to the topics covered?
Which chapters include a section dedicated to problems related to the topics covered?
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What is one advantage of hinged clamps compared to bolt-type clamps?
What is one advantage of hinged clamps compared to bolt-type clamps?
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What feature can be found in a hinged clamp that enhances its operation?
What feature can be found in a hinged clamp that enhances its operation?
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Which type of clamp is described as being suitable for maintaining dimensional accuracy?
Which type of clamp is described as being suitable for maintaining dimensional accuracy?
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What is a characteristic of quick acting clamps?
What is a characteristic of quick acting clamps?
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What mechanism is used in a cam-operated hinged clamp?
What mechanism is used in a cam-operated hinged clamp?
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What is basic function of a C-clamp?
What is basic function of a C-clamp?
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What should be done to unload the workpiece from a C-clamp?
What should be done to unload the workpiece from a C-clamp?
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What type of clamps are more expensive but can simplify operations?
What type of clamps are more expensive but can simplify operations?
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What is the primary purpose of the pin A in the location of the workpiece shown in Fig. 1.11?
What is the primary purpose of the pin A in the location of the workpiece shown in Fig. 1.11?
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Why are pins B positioned further away from the axis of rotation than pin A as shown in Fig. 1.11?
Why are pins B positioned further away from the axis of rotation than pin A as shown in Fig. 1.11?
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What is the main principle behind radial locations, as illustrated in Fig. 1.12?
What is the main principle behind radial locations, as illustrated in Fig. 1.12?
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What type of profile is typically located using a Vee block?
What type of profile is typically located using a Vee block?
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In Fig. 1.12, what does the displacement 'd' at a distance 'a' from the axis O result in?
In Fig. 1.12, what does the displacement 'd' at a distance 'a' from the axis O result in?
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In Fig. 1.11, what is the purpose of the jig or fixture body?
In Fig. 1.11, what is the purpose of the jig or fixture body?
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What is the benefit of positioning the radial locators further away from the axis of rotation?
What is the benefit of positioning the radial locators further away from the axis of rotation?
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What is the primary function of a Vee block?
What is the primary function of a Vee block?
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What is the purpose of relieving pin B in the radial location setup?
What is the purpose of relieving pin B in the radial location setup?
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What is a common way to locate shaft-type workpieces within a jig or fixture?
What is a common way to locate shaft-type workpieces within a jig or fixture?
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What is the purpose of the flattened locator shown in Fig. 1.9?
What is the purpose of the flattened locator shown in Fig. 1.9?
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What is the purpose of the chamfer, cone, or bell mouth at the entrance of a bush?
What is the purpose of the chamfer, cone, or bell mouth at the entrance of a bush?
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Why is the principal locator (pin A) longer than the diamond pin (pin B)?
Why is the principal locator (pin A) longer than the diamond pin (pin B)?
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Which of these is NOT a design principle for locating surfaces in jigs and fixtures?
Which of these is NOT a design principle for locating surfaces in jigs and fixtures?
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What is the primary function of the diamond pin in the flattened locator setup?
What is the primary function of the diamond pin in the flattened locator setup?
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What is the main advantage of using a flattened locator compared to a fully cylindrical locator?
What is the main advantage of using a flattened locator compared to a fully cylindrical locator?
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What is the purpose of the relief provided in locating surfaces?
What is the purpose of the relief provided in locating surfaces?
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What is the purpose of the flange on a bush?
What is the purpose of the flange on a bush?
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What is the purpose of the tolerance 'x' in the work piece dimension?
What is the purpose of the tolerance 'x' in the work piece dimension?
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What is the purpose of the tolerance 'y' in the work holder dimensions?
What is the purpose of the tolerance 'y' in the work holder dimensions?
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Why should a datum or reference surface be established first when locating a workpiece in a jig?
Why should a datum or reference surface be established first when locating a workpiece in a jig?
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What is the primary purpose of a jig or fixture in manufacturing?
What is the primary purpose of a jig or fixture in manufacturing?
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Which of these is NOT a benefit of using a flattened locator?
Which of these is NOT a benefit of using a flattened locator?
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What is the primary function of the movable jaw in the illustration of the V-block?
What is the primary function of the movable jaw in the illustration of the V-block?
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In which scenario should the clamp be strong enough to withstand the reaction imposed upon it?
In which scenario should the clamp be strong enough to withstand the reaction imposed upon it?
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What is the main characteristic of a hook bolt clamp?
What is the main characteristic of a hook bolt clamp?
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What is a key advantage of a bridge clamp?
What is a key advantage of a bridge clamp?
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Why should clamping pressure be directed towards the points of support?
Why should clamping pressure be directed towards the points of support?
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What is the primary goal in designing a clamp?
What is the primary goal in designing a clamp?
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What type of clamp is typically used for lighter clamping tasks?
What type of clamp is typically used for lighter clamping tasks?
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What is the purpose of a slotted strap in the context of a clamping device?
What is the purpose of a slotted strap in the context of a clamping device?
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What issue does the 'bad' scenario in Fig. 1.22(a) demonstrate?
What issue does the 'bad' scenario in Fig. 1.22(a) demonstrate?
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Study Notes
Jigs and Fixtures
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Location Principles:
- Establish a datum (reference surface) early for subsequent machining measurements.
- Minimize locating surfaces for easier cleaning and maintain acceptable wear resistance.
- Ensure locating surfaces do not trap chips/swarf causing misalignment. Provide relief for chip accumulation.
- Locate from machined surface whenever possible.
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Radial Location:
- Position radial locators as far from rotation axis as possible to minimize location errors.
- Use a longer principal locator than a shorter diamond pin to simplify/speed up workpiece location.
- One hole workpieces can be fully located using a principal location pin (e.g., pin A) and two pins (e.g., pin B) restricting movement in the Y-axis.
- A displacement at a distance from the axis results in a smaller angular error at a greater distance from the axis.
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V-Location: Use Vee blocks to locate workpieces with circular or semicircular profiles
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Bush Location: Use hardened steel bushes for shaft-type workpieces to provide a location.
- Press fit small/medium bushes. Push-fit and screw large bushes.
- Flanged bushes provide strength and prevent inadvertent movement.
- Bush entrances should be chamfered/coned/bell-mouthed to facilitate workpiece loading
Clamping Devices
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Clamping Principles:
- Clamps should deliver required clamping force with minimal effort.
- Clamps must withstand largest expected operating force.
- Clamping pressure should direct towards support points to prevent workpiece lifting.
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Types of Clamps:
- Clamping Screws: Used for light clamping.
- Hook Bolt Clamps: Simple, suitable for light work where typical clamp setup is inconvenient.
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Lever Type Clamps:
- Bridge Clamp: Simple, reliable, spring-loaded nut.
- Slotted Strap Clamp: Variation of bridge clamp
- Swinging Latch Clamp: Similar to swinging latch.
- Cam-operated Clamp: Faster than bolt-type, suitable for maintaining accuracy.
- C-Clamps: Free and captive types; allow workpiece removal by unscrewing and freeing the clamp.
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Description
This quiz covers essential principles of jigs and fixtures, including location principles, radial location techniques, and the use of Vee blocks for positioning workpieces. Test your understanding of how to establish effective referencing and minimize errors during machining processes.
