This document contains a question bank with 50 questions and answers related to engineering metrology. Some key points covered include:
- Definitions of accuracy, error, tolerance, fits, and other metrology terms
- Objectives of metrology and types of measuring instruments
- Line and end standards, slip gauges, sine bars, comparators and other measurement tools
- Sources of error, selection of instruments, and calibration
- Tolerances, limits, interchangeability, and gauge design principles
- Angular measurement tools like auto-collimators and protractors
- Surface measurement of roughness and different grading scales
This document discusses different types of screw threads including external and internal threads, right and left hand threads, single and multi-start threads. It provides details on thread specifications such as shape, pitch, diameter, length, number of starts, material, and direction. It then describes various forms of threads including British Standard Fine (BSF), British Standard Pipe (BSP), British Standard Whitworth (BSW), square, acme, knuckle, and buttress threads. It discusses the applications of each thread type and concludes with references used.
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An alloy is a mixture of metals, or a mixture of metal and another element. White metal alloys are those which are light-coloured and generally have a lead or tin base. These alloys are also known as Babbitt metal, or bearing metal, a term which is generally preferred over ‘white metals’. Babbitt metal can be one of several alloys used as a bearing surface in a plain bearing.
Self-energizing brakes use the force of a rotating drum to increase brake pressure. When the brakes are applied while moving forward, the primary shoe moves in the direction of drum rotation, pulling the linked secondary shoe around the anchor pin to force both shoes tighter against the drum. Similarly, when reversing, the secondary shoe moves clockwise to push the primary shoe tighter against the anchor pin, increasing brake pressure.
The piston is a disc that reciprocates within the cylinder. It receives force from expanding gases and transmits energy to the crankshaft. Pistons consist of a head, rings, skirt, and pin. They must withstand pressure and heat while minimizing mass. Common piston materials are cast iron, aluminum alloys, and steels. Piston design considers strength, heat dissipation, sealing, and stress distribution. The thickness of the head, rings, and skirt are calculated based on these factors. Ring design ensures sealing between the piston and cylinder while withstanding pressure and heat.
The document discusses airbags as a safety restraint system in automobiles. It begins by providing background on the development of airbags, noting they were created as a soft cushion to land against in a crash. The basics section explains how airbags work based on Newton's second law of motion to slow a passenger's speed to zero during a collision. The main parts of an airbag are described as the bag itself, made of thin nylon fabric, as well as sensors and an inflation system using hot nitrogen gas. The working section then outlines how the system detects a crash and ignites the nitrogen gas to rapidly inflate the airbag. Modern airbag types including side, curtain, and door airbags are also discussed.
This document defines key terminology used in gear calculations, including:
- Pitch circle - An imaginary circle used to define gear size and motion
- Pitch diameter - The diameter of the pitch circle
- Addendum - The radial distance from the pitch circle to the top of the tooth
- Dedendum - The radial distance from the pitch circle to the bottom of the tooth
- Clearance - The radial distance between the top of one tooth and bottom of the other in mesh
The document discusses measurement and metrology of screw threads. It begins with definitions of screw thread terminology such as major diameter, minor diameter, pitch, angle, and forms of threads. It then describes methods for measuring the major diameter, minor diameter, effective diameter, and pitch of screw threads. The key measurement methods discussed are using micrometers, pitch gauges, and a tool maker's microscope. The goal is to understand principles and techniques for measuring characteristics of screw threads.
This document discusses different types of screw threads including external and internal threads, right and left hand threads, single and multi-start threads. It provides details on thread specifications such as shape, pitch, diameter, length, number of starts, material, and direction. It then describes various forms of threads including British Standard Fine (BSF), British Standard Pipe (BSP), British Standard Whitworth (BSW), square, acme, knuckle, and buttress threads. It discusses the applications of each thread type and concludes with references used.
Visit www.seminarlinks.blogspot.com to download
An alloy is a mixture of metals, or a mixture of metal and another element. White metal alloys are those which are light-coloured and generally have a lead or tin base. These alloys are also known as Babbitt metal, or bearing metal, a term which is generally preferred over ‘white metals’. Babbitt metal can be one of several alloys used as a bearing surface in a plain bearing.
Self-energizing brakes use the force of a rotating drum to increase brake pressure. When the brakes are applied while moving forward, the primary shoe moves in the direction of drum rotation, pulling the linked secondary shoe around the anchor pin to force both shoes tighter against the drum. Similarly, when reversing, the secondary shoe moves clockwise to push the primary shoe tighter against the anchor pin, increasing brake pressure.
The piston is a disc that reciprocates within the cylinder. It receives force from expanding gases and transmits energy to the crankshaft. Pistons consist of a head, rings, skirt, and pin. They must withstand pressure and heat while minimizing mass. Common piston materials are cast iron, aluminum alloys, and steels. Piston design considers strength, heat dissipation, sealing, and stress distribution. The thickness of the head, rings, and skirt are calculated based on these factors. Ring design ensures sealing between the piston and cylinder while withstanding pressure and heat.
The document discusses airbags as a safety restraint system in automobiles. It begins by providing background on the development of airbags, noting they were created as a soft cushion to land against in a crash. The basics section explains how airbags work based on Newton's second law of motion to slow a passenger's speed to zero during a collision. The main parts of an airbag are described as the bag itself, made of thin nylon fabric, as well as sensors and an inflation system using hot nitrogen gas. The working section then outlines how the system detects a crash and ignites the nitrogen gas to rapidly inflate the airbag. Modern airbag types including side, curtain, and door airbags are also discussed.
This document defines key terminology used in gear calculations, including:
- Pitch circle - An imaginary circle used to define gear size and motion
- Pitch diameter - The diameter of the pitch circle
- Addendum - The radial distance from the pitch circle to the top of the tooth
- Dedendum - The radial distance from the pitch circle to the bottom of the tooth
- Clearance - The radial distance between the top of one tooth and bottom of the other in mesh
The document discusses measurement and metrology of screw threads. It begins with definitions of screw thread terminology such as major diameter, minor diameter, pitch, angle, and forms of threads. It then describes methods for measuring the major diameter, minor diameter, effective diameter, and pitch of screw threads. The key measurement methods discussed are using micrometers, pitch gauges, and a tool maker's microscope. The goal is to understand principles and techniques for measuring characteristics of screw threads.
RTM is a low-pressure molding process, where a mixed resin and catalyst are injected into a closed mold containing a fiber pack or preform . when the resin has cured the mold can be opened and finished component removed.
Specimen preparation for micro examination-1yash patel
The document outlines the steps to prepare a specimen for microscopic examination, including cutting, grinding, belt polishing, paper polishing, etching, and examination. Specimens are cut to a convenient size and any irregularities are removed through grinding with an emery wheel or paper. Successive finer grades of emery paper are used to polish the surface. Further polishing is done with cloth or velvet to produce a mirror finish. Etching with acid or chemicals reveals grain and grain boundaries under the microscope. The prepared specimen is then examined under a metallurgical microscope.
The document describes the manufacturing processes used to produce key engine components. Engine blocks are typically made of cast aluminum alloys using a casting process. Pistons are commonly forged from aluminum alloys and undergo machining like cutting, drilling, and milling. Crankshafts are usually made from steel alloys using casting and machining processes like turning, drilling, and grinding. Gears are manufactured through gear forming methods like milling and broaching or gear generation processes like hobbing and shaping.
This document provides information on bearings, including their history, classification, materials used, lubrication types, and design procedures. It discusses how bearings are designed to reduce friction, carry loads, and guide moving parts. The key types are described as radial or thrust bearings, and sliding or rolling contact bearings. Common materials include babbitt metals, bronzes, cast iron, silver, and non-metallic options. Design of journal bearings involves calculating parameters like load capacity, pressure, clearance, heat generation and dissipation. An example at the end illustrates the full design process.
This document provides an overview of bladder curing presses and their components. It describes the bladder, which forms the inside surface of a tire during vulcanization. It explains the principle of bladder dimensioning and the components of a bladder mould. It then contrasts conventional bladder curing presses, which use a ram cylinder, with a newer compact design that lowers the head instead of raising the ram for faster opening and closing cycles. Finally, it lists the sizes and contact information for the manufacturer.
The document summarizes the key steps in the painting process of a car body:
1. The process begins with pre-treatment which includes degreasing, activating, and phosphating the body to prepare the metal surface for painting.
2. Primer is then applied through both manual and robotic spraying to protect and promote adhesion of subsequent paint layers.
3. The primer is baked and sealed before applying the top coat paint through base coating and clear coating.
4. The painted body undergoes a final baking before cavities are sealed to complete the painting process.
Slip gauges are precision rectangular blocks used as standards for linear measurement. They are made of materials like tungsten carbide, chrome-plated steel, and high-grade steel. Slip gauges come in sets designated by their range and accuracy, and are classified according to the precision of work for which they are suited. Proper care must be taken when cleaning, storing, handling, and using slip gauges to maintain their accuracy and prolong their working life.
This document discusses methods for measuring various elements of screw threads, including major diameter, minor diameter, effective diameter or pitch diameter, pitch, flank angle, and thread form. Common measurement tools mentioned include micrometers, thread comparators, thread micrometers, tool makers microscopes, and optical projection. Methods like using setting gauges, V-pieces, taper parallels, rollers and slip gauges, and one-, two-, or three-wire techniques are described for different thread measurements.
Concentric springs, surge phenomenon in spring, helical torsion, spiral springvaibhav tailor
Concentric springs consist of two or more springs placed inside one another. This arrangement increases the overall force and allows tuning of the spring stiffness. Concentric springs can be of equal or unequal lengths. Surge phenomenon occurs when a spring absorbs a suddenly applied load, causing a compression wave to travel along the coils. If the load fluctuations match the wave's travel time, resonance occurs, potentially damaging the spring. Torsion springs use twisting forces rather than compression or tension. Spiral springs store energy through nearly linear winding, making them suitable for small rotational counterbalances.
The document summarizes the key aspects of a Wankel rotary engine. It describes how a rotary engine works differently than a piston engine by having each step of the combustion process occur in a dedicated section of the oval-shaped housing as the rotor continuously rotates. It also notes that rotary engines have fewer moving parts, provide smoother power delivery, and have parts that move more slowly compared to piston engines. However, rotary engines can be more difficult to design to meet emissions regulations and typically have lower thermodynamic efficiency.
This document discusses powder metallurgy and processing of powder metals, ceramics, and glass. It covers the production of metal powders through various methods like compaction and sintering. It also discusses shaping of ceramics through forming and shaping processes as well as design considerations for powder metallurgy, ceramics, and glass. The processing of superconductors is also mentioned.
Line standards and end standards are two categories of instruments used to directly measure linear dimensions.
A line standard measures the distance between the centers of two engraved lines, such as a ruler. It allows for quick measurements over a wide range but lacks precision due to line thickness and susceptibility to parallax errors.
An end standard measures the distance between two parallel flat surfaces, such as slip gauges or a micrometer anvil. It provides highly accurate measurements of close tolerances but is more time-consuming and the faces can wear over time. End standards have a built-in datum for alignment and are not subject to parallax.
Press working is a manufacturing process that uses presses to form sheet metal components. It involves both cutting and non-cutting operations. Common cutting operations include blanking, punching, trimming, and notching. Common non-cutting operations include bending, drawing, and squeezing. A press machine consists of a bed, bolster plate, die set with lower and upper shoes, punches, and other components. The travel of the punch during penetration progresses through three zones: compression, shearing, and breakage. Clearance is applied between the punch and die depending on whether the operation is punching or blanking. Different types of die sets are used depending on the shape and complexity of the part being formed.
1. The document discusses sheet metal forming processes including shearing, bending, and springback. It provides definitions and formulas for calculating forces in shearing and springback in bending.
2. An lab experiment is described that involves bending aluminum strips using a finger brake machine and measuring the resulting bend radii and angles to analyze springback.
3. Finite element analysis simulations are shown illustrating the deformation during bending and springback.
This document summarizes a workshop on heavy-duty fuel efficiency regulations held on April 29th, 2015. It provides an overview of ARAI, the Automotive Research Association of India, including their emission test facilities. It then discusses the status of fuel economy regulations in India, other countries, and at a global level. Highlights of the Indian emission standard IS 11921 are presented. Finally, it proposes a roadmap for developing heavy-duty vehicle fuel economy standards in India and lists existing heavy-duty vehicle testing facilities in the country.
Autoclave is a closed vessel (Round or Cylindrical) in which processes occur under simultaneous application of high temperature and pressure. Autoclave molding technique is similar to vacuum bag and pressure bag molding method with some modifications. This method employs an autoclave to provide heat and pressure to the composite product during curing.
The document discusses melt flow index (MFI) testing for polymers. MFI is a measure of how easily a melted polymer flows and is determined by measuring the mass of polymer that flows through a capillary die over 10 minutes under a standard weight at a set temperature. Higher MFI means better flow properties. The document outlines the components of a melt flow indexer including the barrel for heating pellets, heaters to control temperature, a piston that applies weight, a precisely machined orifice or die, and calibrated weights. Factors that influence polymer MFI are also discussed such as molecular weight, comonomers, branching, and crystallinity.
A calender is a machine that processes polymer melts into sheets or films using heat and pressure between rollers. It works by softening the polymer and passing it through nips between two or more rollers to form a continuous sheet, with the thickness determined by the gap between the last rollers. Common uses of calendered sheets include flooring, rainwear, wall coverings, and signage. Thermoplastics are well-suited for calendering as they can soften without fully melting. Different roller configurations like I, L, and Z types address issues like separating forces between rollers. Calendering is advantageous for heat-sensitive materials but high capital costs and achieving precise thickness can be challenges
1. Surface roughness refers to small irregularities on a surface caused by manufacturing processes, while surface waviness refers to larger, wave-like deviations from a flat surface.
2. Factors that affect surface roughness include cutting parameters, tool and workpiece material, coolants, and vibrations. Factors that affect surface waviness include tool/workpiece deflection, forces, temperature variations, uneven lubrication, and vibration.
3. Surface roughness is measured numerically using direct instrument methods like stylus probes and profilometers or comparison methods like visual inspection and scratch tests. Direct instruments provide quantitative measurements of surface texture.
This document discusses power transmission using belt drives. It begins by introducing belt drives as a system used to transmit power from one mechanical element to another. The main types of belt drives are then described, including flat belts, V-belts, and circular belts. Key terms used in belt drives like driver, driven, tight side, and slack side are also defined. The document then discusses factors for selecting a belt drive system and provides examples of belt drives in various machines. It also covers velocity ratio calculations, slippage calculations, and examples problems determining pulley sizes for required speeds.
Mechanical Engineering Technical Interview Q & A Metrology and precision inst...Er. Bade Bhausaheb
This document discusses various metrology and precision instruments used for measurement and inspection. It provides definitions and explanations of nominal size, actual size, basic size, fits, limits, tolerance, allowance and describes instruments like vernier calipers, micrometers, gauges, sine bars and templates. Key points covered are the working principles and uses of these instruments as well as concepts like interchangeability, selective and non-selective assembly, lapping and honing processes.
For a metric thread of 60° included angle:
Best wire diameter = 0.5774 * Pitch
= 0.5774 * 2.5 = 1.4435 mm
Rounded off to the nearest standard wire size, the best wire size is 1.5 mm.
RTM is a low-pressure molding process, where a mixed resin and catalyst are injected into a closed mold containing a fiber pack or preform . when the resin has cured the mold can be opened and finished component removed.
Specimen preparation for micro examination-1yash patel
The document outlines the steps to prepare a specimen for microscopic examination, including cutting, grinding, belt polishing, paper polishing, etching, and examination. Specimens are cut to a convenient size and any irregularities are removed through grinding with an emery wheel or paper. Successive finer grades of emery paper are used to polish the surface. Further polishing is done with cloth or velvet to produce a mirror finish. Etching with acid or chemicals reveals grain and grain boundaries under the microscope. The prepared specimen is then examined under a metallurgical microscope.
The document describes the manufacturing processes used to produce key engine components. Engine blocks are typically made of cast aluminum alloys using a casting process. Pistons are commonly forged from aluminum alloys and undergo machining like cutting, drilling, and milling. Crankshafts are usually made from steel alloys using casting and machining processes like turning, drilling, and grinding. Gears are manufactured through gear forming methods like milling and broaching or gear generation processes like hobbing and shaping.
This document provides information on bearings, including their history, classification, materials used, lubrication types, and design procedures. It discusses how bearings are designed to reduce friction, carry loads, and guide moving parts. The key types are described as radial or thrust bearings, and sliding or rolling contact bearings. Common materials include babbitt metals, bronzes, cast iron, silver, and non-metallic options. Design of journal bearings involves calculating parameters like load capacity, pressure, clearance, heat generation and dissipation. An example at the end illustrates the full design process.
This document provides an overview of bladder curing presses and their components. It describes the bladder, which forms the inside surface of a tire during vulcanization. It explains the principle of bladder dimensioning and the components of a bladder mould. It then contrasts conventional bladder curing presses, which use a ram cylinder, with a newer compact design that lowers the head instead of raising the ram for faster opening and closing cycles. Finally, it lists the sizes and contact information for the manufacturer.
The document summarizes the key steps in the painting process of a car body:
1. The process begins with pre-treatment which includes degreasing, activating, and phosphating the body to prepare the metal surface for painting.
2. Primer is then applied through both manual and robotic spraying to protect and promote adhesion of subsequent paint layers.
3. The primer is baked and sealed before applying the top coat paint through base coating and clear coating.
4. The painted body undergoes a final baking before cavities are sealed to complete the painting process.
Slip gauges are precision rectangular blocks used as standards for linear measurement. They are made of materials like tungsten carbide, chrome-plated steel, and high-grade steel. Slip gauges come in sets designated by their range and accuracy, and are classified according to the precision of work for which they are suited. Proper care must be taken when cleaning, storing, handling, and using slip gauges to maintain their accuracy and prolong their working life.
This document discusses methods for measuring various elements of screw threads, including major diameter, minor diameter, effective diameter or pitch diameter, pitch, flank angle, and thread form. Common measurement tools mentioned include micrometers, thread comparators, thread micrometers, tool makers microscopes, and optical projection. Methods like using setting gauges, V-pieces, taper parallels, rollers and slip gauges, and one-, two-, or three-wire techniques are described for different thread measurements.
Concentric springs, surge phenomenon in spring, helical torsion, spiral springvaibhav tailor
Concentric springs consist of two or more springs placed inside one another. This arrangement increases the overall force and allows tuning of the spring stiffness. Concentric springs can be of equal or unequal lengths. Surge phenomenon occurs when a spring absorbs a suddenly applied load, causing a compression wave to travel along the coils. If the load fluctuations match the wave's travel time, resonance occurs, potentially damaging the spring. Torsion springs use twisting forces rather than compression or tension. Spiral springs store energy through nearly linear winding, making them suitable for small rotational counterbalances.
The document summarizes the key aspects of a Wankel rotary engine. It describes how a rotary engine works differently than a piston engine by having each step of the combustion process occur in a dedicated section of the oval-shaped housing as the rotor continuously rotates. It also notes that rotary engines have fewer moving parts, provide smoother power delivery, and have parts that move more slowly compared to piston engines. However, rotary engines can be more difficult to design to meet emissions regulations and typically have lower thermodynamic efficiency.
This document discusses powder metallurgy and processing of powder metals, ceramics, and glass. It covers the production of metal powders through various methods like compaction and sintering. It also discusses shaping of ceramics through forming and shaping processes as well as design considerations for powder metallurgy, ceramics, and glass. The processing of superconductors is also mentioned.
Line standards and end standards are two categories of instruments used to directly measure linear dimensions.
A line standard measures the distance between the centers of two engraved lines, such as a ruler. It allows for quick measurements over a wide range but lacks precision due to line thickness and susceptibility to parallax errors.
An end standard measures the distance between two parallel flat surfaces, such as slip gauges or a micrometer anvil. It provides highly accurate measurements of close tolerances but is more time-consuming and the faces can wear over time. End standards have a built-in datum for alignment and are not subject to parallax.
Press working is a manufacturing process that uses presses to form sheet metal components. It involves both cutting and non-cutting operations. Common cutting operations include blanking, punching, trimming, and notching. Common non-cutting operations include bending, drawing, and squeezing. A press machine consists of a bed, bolster plate, die set with lower and upper shoes, punches, and other components. The travel of the punch during penetration progresses through three zones: compression, shearing, and breakage. Clearance is applied between the punch and die depending on whether the operation is punching or blanking. Different types of die sets are used depending on the shape and complexity of the part being formed.
1. The document discusses sheet metal forming processes including shearing, bending, and springback. It provides definitions and formulas for calculating forces in shearing and springback in bending.
2. An lab experiment is described that involves bending aluminum strips using a finger brake machine and measuring the resulting bend radii and angles to analyze springback.
3. Finite element analysis simulations are shown illustrating the deformation during bending and springback.
This document summarizes a workshop on heavy-duty fuel efficiency regulations held on April 29th, 2015. It provides an overview of ARAI, the Automotive Research Association of India, including their emission test facilities. It then discusses the status of fuel economy regulations in India, other countries, and at a global level. Highlights of the Indian emission standard IS 11921 are presented. Finally, it proposes a roadmap for developing heavy-duty vehicle fuel economy standards in India and lists existing heavy-duty vehicle testing facilities in the country.
Autoclave is a closed vessel (Round or Cylindrical) in which processes occur under simultaneous application of high temperature and pressure. Autoclave molding technique is similar to vacuum bag and pressure bag molding method with some modifications. This method employs an autoclave to provide heat and pressure to the composite product during curing.
The document discusses melt flow index (MFI) testing for polymers. MFI is a measure of how easily a melted polymer flows and is determined by measuring the mass of polymer that flows through a capillary die over 10 minutes under a standard weight at a set temperature. Higher MFI means better flow properties. The document outlines the components of a melt flow indexer including the barrel for heating pellets, heaters to control temperature, a piston that applies weight, a precisely machined orifice or die, and calibrated weights. Factors that influence polymer MFI are also discussed such as molecular weight, comonomers, branching, and crystallinity.
A calender is a machine that processes polymer melts into sheets or films using heat and pressure between rollers. It works by softening the polymer and passing it through nips between two or more rollers to form a continuous sheet, with the thickness determined by the gap between the last rollers. Common uses of calendered sheets include flooring, rainwear, wall coverings, and signage. Thermoplastics are well-suited for calendering as they can soften without fully melting. Different roller configurations like I, L, and Z types address issues like separating forces between rollers. Calendering is advantageous for heat-sensitive materials but high capital costs and achieving precise thickness can be challenges
1. Surface roughness refers to small irregularities on a surface caused by manufacturing processes, while surface waviness refers to larger, wave-like deviations from a flat surface.
2. Factors that affect surface roughness include cutting parameters, tool and workpiece material, coolants, and vibrations. Factors that affect surface waviness include tool/workpiece deflection, forces, temperature variations, uneven lubrication, and vibration.
3. Surface roughness is measured numerically using direct instrument methods like stylus probes and profilometers or comparison methods like visual inspection and scratch tests. Direct instruments provide quantitative measurements of surface texture.
This document discusses power transmission using belt drives. It begins by introducing belt drives as a system used to transmit power from one mechanical element to another. The main types of belt drives are then described, including flat belts, V-belts, and circular belts. Key terms used in belt drives like driver, driven, tight side, and slack side are also defined. The document then discusses factors for selecting a belt drive system and provides examples of belt drives in various machines. It also covers velocity ratio calculations, slippage calculations, and examples problems determining pulley sizes for required speeds.
Mechanical Engineering Technical Interview Q & A Metrology and precision inst...Er. Bade Bhausaheb
This document discusses various metrology and precision instruments used for measurement and inspection. It provides definitions and explanations of nominal size, actual size, basic size, fits, limits, tolerance, allowance and describes instruments like vernier calipers, micrometers, gauges, sine bars and templates. Key points covered are the working principles and uses of these instruments as well as concepts like interchangeability, selective and non-selective assembly, lapping and honing processes.
For a metric thread of 60° included angle:
Best wire diameter = 0.5774 * Pitch
= 0.5774 * 2.5 = 1.4435 mm
Rounded off to the nearest standard wire size, the best wire size is 1.5 mm.
The document discusses various methods for measuring lines, surfaces, and geometries. It describes common measurement tools like vernier calipers, micrometers, bore gauges, dial indicators, and slip gauges. It also covers methods for measuring threads, angles, and surface roughness. Key aspects include using a vernier scale to improve measurement resolution, using wire methods to measure thread pitch diameters, and parameters like roughness height and width to characterize surface texture.
Slip gauges are rectangular blocks of hardened steel used to measure linear dimensions precisely. They are manufactured to high tolerances through processes like hardening, grinding, and lapping. Different grades have varying accuracies. Accessories like holders and measuring jaws aid slip gauge use. Angles can be measured using a sine bar and slip gauges based on trigonometric relationships between the height of slip gauges and the sine bar's fixed roller distance. Auto-collimators also precisely measure small angles using reflected light.
This document discusses interchangeable parts and interchangeability. It defines an interchangeable part as one that can be substituted for a similar part manufactured to the same drawing. Interchangeability means that any component can assemble properly with any mating component chosen at random. The document also discusses the history of interchangeability and its benefits like easier assembly, increased production rates, and lower assembly costs.
This document discusses measurement and inspection techniques used in manufacturing. It covers topics such as interchangeability, dimensional tolerances, measurement instruments including calipers, micrometers and dial indicators, and surface texture. Interchangeable parts allow for easy assembly and repair of devices while minimizing time and skill required. Dimensional tolerances and proper measurement are important for ensuring interchangeability and quality control. A variety of tools are used to accurately measure dimensions and inspect parts.
This document discusses limits, fits, tolerances and surface roughness. It defines standardization and interchangeability, explaining their benefits. It describes limit systems and the terminology used, including types of fits. Clearance, interference and transition fits are defined. Surface roughness is discussed, including how it is measured and expressed. Preferred number series for dimensions are also covered.
This document provides instructions for experiments to be conducted in a metrology lab. It includes 10 experiments involving calibration of measurement tools like micrometers and dial gauges using slip gauges, measurement of angles using a bevel protractor and sine bar, measurement of gear features, surface roughness, and more. The document was prepared by B.Sudarshan, Assistant Professor of Mechanical Engineering, for students to record their experiment details, objectives, theories, procedures, observations and results.
The document discusses mechanical measurements and metrology. It covers topics like limits, fits, tolerances and gauging. Specifically, it defines tolerance, describes different types of tolerances like unilateral, bilateral and compound. It also discusses interchangeability, selective assembly, fits, tolerance grades and general terminology used in metrology like basic size, actual size, deviations etc. The objective is to equip students with knowledge of these important concepts in mechanical measurements.
The document provides an overview of metrology and coordinate metrology techniques. It discusses measurement methods and sources of uncertainty. It introduces geometric dimensioning and tolerancing (GD&T) symbols and concepts like datum, maximum material condition, and least material condition. Advanced metrological instruments like coordinate measuring machines (CMMs) are described along with their applications.
This document discusses metrology, which is the science of measurement. It covers key concepts in metrology including standards of measurement, accuracy vs precision, limits, fits and tolerances.
The document is divided into six modules which cover topics such as comparison measurement tools, screw thread and gear measurement, quality control principles, and statistical process control tools. Measurement standards including line, end, and wavelength standards are explained. International tolerance grades and limits of size are also summarized.
The document discusses various topics related to metrology. It begins by defining metrology as the science of measurement and dividing it into two main types - industrial metrology and medical metrology. Some key points covered include the importance of length and time measurements, analyzing measurement errors, gauges design and manufacturing, and industrial inspection. It also discusses types of metrology like scientific, industrial, legal and fundamental metrology. Specific measuring instruments like vernier calipers, micrometers, and slip gauges are explained in detail. The document concludes by covering various other metrology topics such as measurement principles, linear measuring instruments, and applications of limit gauges.
Okay, here are the steps to solve this problem:
1) D = Geometric mean of lower and upper limit = √30 x 50 = 38.27 mm
2) i = 0.45 x 38.271/3 + 0.001 x 38.27 = 1.307 μm
3) For H7 hole:
Tolerance grade (IT7) = 25i = 32.5 μm = 0.0325 mm
4) Fundamental deviation for H hole = 0
So, hole limits are: 50 mm and 50 + 0.0325 = 50.0325 mm
Hole tolerance = 0.0325 mm
5) For g6 shaft:
Tolerance grade (IT
Medición de los parámetros "twist" de rugosidad, nuevos requerimientos de medición en la industria automotriz. Jenoptik a incorporado la metodología y evaluación de este parámetro en nuestros software.
Person A is more accurate since their measurements are closer to the true length of 17.0 cm. Person B is more precise since their measurements are more consistent even though they are not as close to the true length.
This document provides an overview of mechanical measurements and metrology. It discusses key concepts like accuracy, precision, types of errors in measurement, calibration, standards, and classification of measuring instruments. The objectives of metrology are outlined as ensuring measuring instruments are adequate and maintained through calibration. Factors affecting measurement accuracy are explored including the standard, workpiece, instrument, operator, and environment. Common methods of measurement and classification of instruments are also summarized.
This document provides an overview of metrology and measurements. It discusses key concepts in metrology including calibration, traceability, uncertainty, and accreditation. It defines metrology as the science of measurement and explains its importance. Metrology covers defining measurement units, establishing measurement standards, and documenting measurement accuracy. There are different categories of metrology including scientific, industrial, and legal metrology. The document also discusses various measurement tools and gauges used in industrial metrology.
Module 2 part i limits, fits, and tolerancessubhashFTVET
The document discusses limits, fits, and tolerances in manufacturing. It defines key terms like basic size, tolerance, deviation, allowance and different types of fits and tolerances. Tolerance is specified to indicate the permissible variation in a part's actual size from its nominal dimensions. Allowance refers to the intentional difference between mating features to achieve a desired fit. The document also discusses principles of interchangeability and how tolerances are accumulated in an assembly. Maximizing interchangeability requires minimizing the effects of tolerance stacking.
This document appears to be a laboratory manual for an Automotive Mechanical Measurements course at Indus University Ahmedabad. It contains instructions, theories, objectives and procedures for 8 experiments involving precision measurement instruments, linear and angular measurements, calibration of instruments, surface roughness measurement, gear measurement, and measurement of pressure, temperature and flow. The manual provides observation tables and sample calculations for students to record their results during experiments and includes questions at the end of each experiment section.
The document discusses several engineering thermoplastics including polyamides (nylons), polyoxymethylene (POM/acetals), polyesters (PBT and PET), polycarbonate (PC), and polyphenylene oxide (PPO). It provides details on the structure, properties, synthesis, processing, applications of each polymer. For polyamides, it specifically discusses nylon 6, nylon 6,6, nylon 6,10, nylon 11, and nylon 12. It compares the characteristics and performance properties of nylon 6 and nylon 6,6.
The document discusses the central lathe machine. A lathe is a machine tool that holds and rotates a workpiece about an axis to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, and turning with tools that are applied to the workpiece to create an object with symmetry about an axis. The main components of a lathe include the bed, headstock, carriage, tailstock, and lead screw/feed rod. The workpiece is held and rotated between centers or clamped in a chuck or faceplate while a cutting tool is advanced into the workpiece to remove material.
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1. Page 1 of 5
CENTRAL INSTITUTE OF PLASTICS ENGINEERING & TECHNOLOGY
GUINDY, Chennai-600 032
Question Bank
COURSE: DPMT
SEMESTER: III
SUBJECT: Engineering Metrology
Section – B
(2 mark – questions)
1. Define Accuracy.
Ans: It can be defined as “the closeness of the measured value with the true value”. Accuracy
is the degree to which the measured value agrees with the true value of the measured
quantity.
2. What is Error and what are the sources of error.
Ans: Error may be defined as the quantity which is equal to the difference between true value
and the value found by measurement (indicated value).
Sources of Error:
1. Defect in instruments.
2. Manual adjustment of an instrument.
3. Manufacturing defect in instrument.
3. List the Objectives of Metrology.
Ans: It plays important role in every field of inspection.
It can be used to achieve standardization.
It can be used to find out the sources of errors.
4. What is Line Standard?
Ans: Line standard is the standard in which distance is measured between two lines or two
surfaces. It is quick and easy. It is not suitable for close tolerance length measurement.
Parallax error can occur in measurement.
5. Define the measuring instrument?
Ans: measuring devices transform the measured quantity or a related quantity into an
indication or information.
6. What is the process of selection of Measuring Instruments?
Ans: Range of measurement carried by the instrument. Sensitivity of the Instrument.
7. Define End Standard.
Ans: When length is expressed as distance between the two flat parallel surfaces then it is
called as End Standard.
8. What are Angular Measuring Instruments?
Ans: The angle measuring instruments are:
1. Sine Bars 2. Sine Centre’s 3. Auto-Collimator 4. Bevel Protractor 5. Taper plug.
9. Write about the Slip gauges?
Ans: Slip gauges or gauge blocks may be used as reference standards for transferring the
dimension of the unit of length from the primary standard to gauge blocks of lower accuracy
and for verification and graduation of measuring apparatus.
10. What is sine bar?
Ans: The slip gauges can be used for measurement of angles with the help of a simple piece
of apparatus known as sine bar. It is a hardened steel beam mounted on two hardened equal
diameter cylinders at known distance.
11. Define Auto Collimator.
Ans: It is an optical instrument used for measuring small angular differences. It provides a
very sensitive and accurate approach for small angular measurements. It consists of three
main parts viz, micrometer microscope, lighting unit (source of light) and collimating lens.
2. Page 2 of 5
12. How the interchangeability plays a vital role in metrology?
Ans: An interchangeable component is one which can be substituted for similar part
manufactured to the same drawing. Interchangeability is possible when certain standards are
strictly followed in different manufacturing plants.
13. What is Nominal Size?
Ans: It is used for the purpose of identification of a component. It is the size by which it is
specified in a drawing as a matter of convenience. It is never used in precision
measurements.
14. What is Basic Size?
Ans: It is the standard size of a component with reference to which all the limits of variation of
size are found. It is same for hole and corresponding shaft.
15. Define Limit?
Ans: Limit refers to the two extreme permissible values between which the actual size of a
component is present. It can be classified as maximum limit (upper limit) and minimum limit
(lower limit) of size.
16. Define Tolerance.
Ans: It is the algebraic difference between the maximum limit and minimum limit of a hole or a
shaft. It can also be defined as the difference between the upper deviation and lower
deviation and it has an absolute value without sign.
17. What is Fit? What are the different types of fits?
Ans: When two parts are to be assembled, the relation resulting from the difference between
their sizes before assembly is called as fit. It is the degree of tightness or looseness between
the two mating parts to perform a particular function. The fits may be classified as i)
Clearance fit ii) Interference fit iii) Transition fit.
18. What is Hole basis system?
Ans: In this system, the hole size is kept constant and the shaft diameter is varied to get the
different types of fits. The hole has constant high and low limits for all fits of the same
accuracy and grade. It is denoted by ‘H’.
19. What is Shaft basis system?
Ans: In this system, the shaft size is kept constant and the hole size is varied to get the
different types of fits. In this case, the design size of a shaft whose upper deviation is zero is
assumed as basic size. It is denoted by ‘h’.
20. What is the difference between Gauges and Instruments?
Ans:
Gauges:
These are inspection tools without any scale arrangements. It does not give actual readings
of a component. Gauges have limited application.
Instruments:
These are measuring tools with calibrated scale arrangements. It gives actual readings of a
component. Instruments have wide range of applications.
21. What type of gauges can be used to measure or test the surface of a machined work piece?
Ans: Plug gauges and Snap gauges are used to measure the test surface of a machined work
piece.
22. What is comparator? What are the applications of comparators?
Ans: The comparator is a precision type of instrument which enables a comparison between
the part being measured and a length standard. These are used for inspecting newly
purchased gauges. It can be used as a laboratory standard from which working gauges can
be set by comparison.
23. Define CMM and its types.
Ans: CMM is Co-ordinate Measuring Machines are used for post process inspection, where
the work piece is removed from the machine tool and taken to CMM. Types are: i) Cantilever
type ii) Bridge type iii) Column type iv) Gantry type.
3. Page 3 of 5
24. Write about the Tool Makers Microscope?
Ans: Tool Makers Microscope is a versatile optical measuring machine. It is a direct reading
type measuring instrument and mainly used in inspection of gauges, tools, screw threads,
jigs, fixtures, dies, etc. It is used for external and internal length measurement, curvatures,
angles etc.
25. List the different types of comparator.
Ans: i) Mechanical Comparator ii) Optical Comparator iii) Pneumatic Comparator iv) Electrical
Comparator v) Mechanical Optical Comparator.
26. Define Bilateral Tolerance.
Ans: When one limit of size is on one side of zero line and other limit of size is on other side of zero
line then the specified tolerance is called as bilateral tolerance.
For example: 30
+_0.02
27. List the classification of standards depending upon the importance and accuracy required for the
work.
Ans: 1. Primary Standards.
2. Secondary Standards.
3. Tertiary Standards.
4. Working standards.
28. Define repeatability.
Ans: It is the ability of the measuring instrument to repeat the same results when measurements are
carried out:
by same observer
With the same instrument.
Under the same conditions.
Without any change in location.
Without change in the method of measurement.
29. Write about the clearance fit.
Ans: If the dimension of shaft is less than the dimension of hole even in the case of maximum material
condition of hole & shaft, it is called clearance fit.
30. What is interchangeability?
Ans: Manufacture of machine tools, automobiles, IC engines, aircraft etc requires thousands of
components which are identical. In such large scale production each male component should fit with
corresponding female component without interchanging the parts present in a lot of identical items.
31. Define Taylor’s principle of gauge design.
Ans: Limit gauges are designed based on Taylor’s principle. It states that (i) Go gauges should be
designed to check the maximum material limit while the No-Go gauges should be designed to check
the minimum material limit of shaft/hole.
32. Write about the Interferometer.
Ans: Interferometers are optical instrument used for measuring flatness and determining the length of
slip gauges. They are based upon the interference principle and employ wavelength of light as their
measuring units.
33. What is surface roughness and what are the sources of it?
Ans: Surface roughness is nothing but repetitive or random deviation from the nominal surface.
surface. The irregularities on the surface are in the form of succession of hills and valleys varying in
height and spacing. These irregularities are named as: surface roughness, finish, texture & quality.
34. List the roughness values along with the manufacturing process.
Ans:
.
S.No. Manufacturing Process Ra value in microns
1. Lapping 0.012 – 0.16
2. Super finishing 0.016 – 0.32
3. Honing 0.025 – 0.04
4. Polishing 0.04 – 0.16
4. Page 4 of 5
35. List the roughness symbols along with the roughness grade symbol.
Ans:
36. Define the zero line.
Ans: The line corresponding to basic size is called as zero line. This has zero deviation. The positive
deviations are above the zero line and negative deviations are below the zero line.
37. What is the need of tolerance?
Ans: It is never possible to make a component of actual given size and no method is available for
accurate measurement of that size. It is difficult to produce a component of exact size due to
variations in material properties of product and production machines themselves have some inherent
accuracy in them and human error.
38. Define Sine Centre.
Ans: Sine centre is a sine bar with block holding centre’s which can be adjusted and rigidly clamped in
any position. It is mainly used for inspection of conical components which are centered at each end.
The alignment accuracy of the centres ensures that the correct line of measurement is made along
the work piece.
39. What is the Angle Gauge?
Ans: Angle gauges are wedge shaped block of hardened and stabilized steel. They can be used as
standard for angle measurement. The measuring faces of angle gauges are lapped and polished to
high degree of accuracy and flatness. These are 76 mm long and 16 mm wide.
40. Write about the Auto Collimator.
Ans: It is an optical instrument used for measuring small angular differences. It provides a very
sensitive and accurate approach for small angular measurements. It is a telescope used for
collimating other instruments. It converts the light rays into a parallel beam of light.
41. Write about the Dial Indicator?
Ans: It is the most commonly used mechanical comparator. It consists of solid base with perfectly flat
surface and column carries a bracket on which spindle and indicator are mounted. The linear
movement of the plunger is magnified with the help of gear train into the rotation of pointer on the
scale.
42. List the various LASER techniques used in metrology for measurements?
Ans: Following are some LASER techniques used in metrology for measurements:
i) Scanning laser Gauge
ii) Photo diode array imaging
iii) Diffraction pattern techniques
iv) Laser triangulation sensors
v) Two frequency laser interferometer
vi) Laser scanning gauge
S.No. Ra value in microns Roughness grade symbols
1. 50 ~
2. 12.5 – 25.0 ▼
3. 1.6 – 6.3 ▼▼
4. 0.2 – 0.8 ▼▼▼
5. 0.025 – 0.1 ▼▼▼▼
5. Page 5 of 5
43. What are the different grades of slip gauges?
Ans: Slip gauges are divided in five grades, they are as mentioned below:
Grade II: These grades are used in workshop for rough checks and in ordinary inspection work.
Grade I: These are used for precise work such as measurement of tools, sine bar etc.
Grade 0: These are also known as inspection grades used in tool room for inspection.
44. Define the Calibration.
Ans: It is the process of checking the accuracy of the measuring instruments or the dimensions and
tolerances of a gauge by comparing it with same or standard instrument/gauge which has been
certified as per the standards.
45. What is Error and types of error?
Ans: Error may be defined as the quantity which is equal to the difference between true value and the
value found by measurement (indicated value).
Mathematically, Error = True value – Indicated value.
1) Systematic Error (controllable error) 2) Random error.
46. Define the Uncertainty of Measurement.
Ans: Instruments always give slightly different value of a measured quantity with repeated
instruments. Uncertainty of measurement is that part of the result of measurement which states the
range of values within which the true value is estimated to lie. It denotes the degree of accuracy with
which the measurement has been made.
47. Write about the wringing of slip gauges.
Ans: The accuracy of measurement depends on the phenomenon of wringing. The slip gauges are
wrung together by hand through a combined sliding and rising motion. The gap between 2 wrung slip
gauges is only of the order of 0.00635 microns which is negligible.
48. Write the difference between tolerance and allowance.
Ans: Tolerance: It is the permissible variation in dimension of a part either a hole (or a shaft). It is
also the difference between higher and lower limits of dimensions of a part.
Allowance: It is the prescribed difference between the dimensions of two mating parts (hole and
shaft). It is the difference between the maximum shaft and minimum hole size.
49. Define about the Optical flats.
Ans: Optical flat works on the principle of light interference. It is made of any transparent material
usually glass or quartz with 2 highly polished parallel flat surfaces. The yellow orange light eradicated
by helium gas is most satisfactorily for use with optical flat. For greater accuracy of optical flat it must
be used in areas where the temperature is constant.
50. List the advantages and disadvantages of limit gauges.
Ans: Advantages: It can be used in mass production at relatively low cost. It is a faster inspection
method which leads to increase in productivity. It confirms the interchangeability of the component so
that they are easy to assemble.
Disadvantages: It only indicates that whether the component is in specified limit or not. It does not
give any information about its actual dimensions. While checking wear phenomenon may introduced
and with the limit gauges it is difficult to check component with finer tolerance.
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