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Answer any three of the following: (i) Identify three safety features integrated into a lathe - Leaving Cert Engineering - Question 7 - 2016
Question 7
Answer any three of the following: (i) Identify three safety features integrated into a lathe. (ii) Explain how measurement errors may occur when using digital ver... show full transcript
Worked Solution & Example Answer:Answer any three of the following: (i) Identify three safety features integrated into a lathe - Leaving Cert Engineering - Question 7 - 2016
Step 1
(i) Identify three safety features integrated into a lathe.
Answer
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Emergency Stop Button: This feature allows the operator to quickly halt the operation of the lathe in case of an emergency, ensuring immediate safety.
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Chuck Interlocking Guard: This safety mechanism prevents the lathe from operating when the chuck guard is not in place, reducing the risk of accidents.
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Leadscrew Guard: A protective cover that prevents contact with the moving leadscrew, minimizing the risk of injury from rotating parts.
Step 2
(ii) Explain how measurement errors may occur when using digital vernier calipers.
Answer
Measurement errors can occur due to several factors:
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Misalignment: If the object is not properly aligned with the calipers' jaws, inaccurate readings will result.
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Battery Issues: A weak battery can cause the digital display to malfunction, leading to incorrect measurements.
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Damaged Jaws: If the measuring jaws are damaged or chipped, this can affect the accuracy of the reading.
Step 3
Step 4
(iv) Distinguish between a pilot hole and a tapping size hole.
Answer
A pilot hole is a small hole drilled prior to creating a larger hole; it aids in guiding the larger drill bit. It is slightly smaller than the subsequent hole. A tapping size hole is drilled specifically for threading; this hole is smaller than the tap size to ensure proper thread formation based on the tap's pitch.
Step 5
(b) (i) Outline two reasons why a sealed lubrication system is used in engineering machines.
Answer
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Reduced Friction: Sealed systems minimize friction between moving parts, which enhances machine efficiency and prolongs the life of components.
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Heat Management: They help in dissipating heat more effectively, preventing overheating that could damage the machine.
Step 6
(b) (ii) Identify any two lubricating materials commonly used in engineering machines.
Answer
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Oil: Commonly used for its excellent lubricating properties and ability to resist heat.
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Graphite: Sometimes used as a dry lubricant; beneficial in high-temperature applications where liquid lubricants may fail.
Step 7
(c) (i) Describe briefly how the tungsten carbide inserts are manufactured.
Answer
The manufacturing of tungsten carbide cutting tool inserts involves several steps:
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Mixing: Carbon black, tungsten metal, and metal oxides are combined and heated within a carbon atmosphere.
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Powder Preparation: Tungsten carbide powder is mixed with wax and cobalt, and thoroughly mixed in a ball mill to achieve a fine powder.
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Molding: The fine powder is placed into a mold and pressed into shape.
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Sintering: The molded inserts are heated in a high-pressure atmosphere to harden the material.
Step 8
(c) (ii) Outline two advantages and two disadvantages of an interchangeable tungsten carbide insert.
Answer
Advantages:
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High Cutting Efficiency: Tungsten carbide inserts retain their cutting edges at elevated temperatures better than high-speed steel (HSS).
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Long Tool Life: They require less frequent replacement, which increases operational efficiency.
Disadvantages:
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Cost: Tungsten carbide inserts are more expensive compared to traditional inserts, impacting initial setup costs.
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Brittleness: These inserts can be prone to chipping and fracture under extreme conditions.