A small reaserch on
Belts, Rope and Chain Drives
Prepared By
Mr. GAUTAM SAURAV
Acknoledgement
I would like to express my greatest gratitude to the people who have helped & supported me throughout my term paper. I am grateful to my teacher Miss Shivani Arora for her continuous support for the project, from initial advice & contacts in the early stages of conceptual inception & through ongoing advice & encouragement to this day.
A special thank of mine goes to my colleague who helped me in completing the term paper & she exchanged her interesting ideas, thoughts & made this project easy and accurate.
I wish to thank my parents for their undivided support and interest who inspired me and encouraged me to go my own way, without whom I would be unable to complete my project. At last but not the least I want to thank my friends who appreciated me for my work and motivated me and finally to God who made all the things possible...
thank you all....................
by
Mr. Gautam Saurav
Content
A. Belt
1.Belt
2.Power Transmission
3.Types of Belt
3.1Flat Belts
3.2 Round Belts
3.3Vee Belts
3.4Multi Grooved Belt
3.5Ribbed Belts
3.6Film Belts
3.7Timing Belt
3.8Speciality Belts
4.Uses of belt
4.1. Rolling Roads
4.2. Standard for Use
5.Selection Criteria
B. Rope
1.Rope
2.Construction
3.Usage
4.Types of Ropes
4.1 Rock Climbing Roads
4.2 Laid or Twisted Ropes
4.3 Braided Rope
4.4 Flying Rope
4.5 Handling Rope
5.Some Other Types
C. Chain Drives
1.Introduction
2.Chains Versus Belt
3.Use In Vehicles
3.1 Bicycles
3.2 Automobiles
3.2.1 Transmitting Power To The Wheels
3.2.2 Inside Motors
Belt
1. Introduction
A belt is a loop of flexible material used to link two or more rotating shafts mechanically. Belts may be used as a source of motion, to transmit power efficiently, or to track relative movement. Belts are looped over pulleys. In a two pulley system, the belt can either drive the pulleys in the same direction, or the belt may be crossed, so that the direction of the shafts is opposite. As a source of motion, a conveyor belt is one application where the belt is adapted to continually carry a load between two points.
2. Power transmission
Belts are the cheapest utility for power transmission between shafts that may not be axially aligned. Power transmission is achieved by specially designed belts and pulleys. The demands on a belt drive transmission system are large and this has led to many variations on the theme. They run smoothly and with little noise, and cushion motor and bearings against load changes, albeit with less strength than gears or chains. However, improvements in belt engineering allow use of belts in systems that only formerly allowed chains or gears.
3. Types of Belt
3.1. Flat belts
The drive belt: used to transfer power from the engine's flywheel. Here shown driving a threshing machine.
Flat belts were used early in line shafting to transmit power in factories. It is a simple system of power transmission that was well suited for its day. It delivered high power for high speeds (500hp for 10,000ft/min), in cases of wide belts and large pulleys. These drives are bulky, requiring high tension leading to high loads, so vee belts have mainly replaced the flat-belts except when high speed is needed over power. The Industrial Revolution soon demanded more from the system, and flat belt pulleys needed to be carefully aligned to prevent the belt from slipping off. Because flat belts tend to climb towards the higher side of the pulley, pulleys were made with a slightly convex or "crowned" surface (rather than flat) to keep the belts centered. Flat belts also tend to slip on the pulley face when heavy loads are applied and many proprietary dressings were available that could be applied to the belts to increase friction, and so power transmission. Grip was better if the belt was assembled with the hair (i.e. outer) side of the leather against the pulley although belts were also often given a half-twist before joining the ends , so that wear was evenly distributed on both sides of the belt (DB). Belts were joined by lacing the ends together with leather thonging, or later by steel comb fasteners. A good modern use for a flat belt is with smaller pulleys and large central distances. They can connect inside and outside pulleys, and can come in both endless and jointed construction
3.2. Round belts
Round belts are a circular cross section belt designed to run in a pulley with a circular (or near circular) groove. They are for use in low torque situations and may be purchased in various lengths or cut to length and joined, either by a staple, gluing or welding . Early sewing machines utilized a leather belt, joined either by a metal staple or glued, to a great effect.
3.3. Vee belts
Vee belts (also known as V-belt or wedge rope) solved the slippage and alignment problem. It is now the basic belt for power transmission. They provide the best combination of traction, speed of movement, load of the bearings, and long service life. The V-belt was developed in 1917 by of the Gates Rubber Company. They are generally endless, and their general cross-section shape is John Gtes trapezoidal. The "V" shape of the belt tracks in a mating groove in the pulley (or sheave), with the result that the belt cannot slip off. The belt also tends to wedge into the groove as the load increases— the greater the load, the greater the wedging action— improving torque transmission and making the V-belt an effective solution, needing less width and tension than flat belts. V-belts trump flat belts with their small center distances and high reduction ratios. The preferred center distance is larger than the largest pulley diameter, but less than three times the sum of both pulleys. Optimal speed range is 1000–7000ft/min. V-belts need larger pulleys for their larger thickness than flat belts. They can be supplied at various fixed lengths or as a segmented section, where the segments are linked (spliced) to form a belt of the required length. For high-power requirements, two or more vee belts can be joined side-by-side in an arrangement called a multi-V, running on matching multi-groove sheaves. The strength of these belts is obtained by reinforcements with fibers like steel, polyester or aramid. This is known as a multiple-V-belt drive (or sometimes a "classical V-belt drive"). When an endless belt does not fit the need, jointed and link V-belts may be employed. However they are weaker and only usable at speeds up to 4000ft/min. A link v-belt is a number of rubberized fabric links held together by metal fasteners. They are length adjustable by disassembling and removing links when needed.
3.4. Multi-groove belts
A multi-groove or polygroove belt is made up of usually 5 or 6 "V" shapes along side each other. This gives a thinner belt for the same drive surface, thus is more flexible, although often wider. The added flexibility offers an improved efficiency, as less energy is wasted in the internal friction of continually bending the belt. In practice this gain of efficiency is overshadowed by the reduced heating effect on the belt, as a cooler-running belt lasts longer in service.
A further advantage of the polygroove belt, and the reason they have become so popular, stems from the ability to be run over pulleys on the ungrooved back of the belt. Although this is sometimes done with vee belts and a single idler pulley for tensioning, a polygroove belt may be wrapped around a pulley on its back tightly enough to change its direction, or even to provide a light driving force.
Any vee belt's ability to drive pulleys depends on wrapping the belt around a sufficient angle of the pulley to provide grip. Where a single-vee belt is limited to a simple convex shape, it can adequately wrap at most three or possibly four pulleys, so can drive at most three accessories. Where more must be driven, such as for modern cars with power steering and air conditioning, multiple belts are required. As the polygroove belt can be bent into concave paths by external idlers, it can wrap any number of driven pulleys, limited only by the power capacity of the belt.
This ability to bend the belt at the designer's whim allows it to take a complex or "serpentine" path. This can assist the design of a compact engine layout, where the accessories are mounted more closely to the engine block and without the need to provide movable tensioning adjustments. The entire belt may be tensioned by a single idler pulley.
3.5. Ribbed belt
A ribbed belt is a power transmission belt featuring lengthwise grooves. It operates from contact between the ribs of the belt and the grooves in the pulley. Its single-piece structure it reported to offer an even distribution of tension across the width of the pulley where the belt is in contact, a power range up to 600kW, a high speed ratio, serpentine drives (possibility to drive off the back of the belt), long life, stability and homogeneity of the drive tension, and reduced vibration. The ribbed belt may be fitted on various applications: compressors, fitness bikes, agricultural machinery, food mixers, washing machines, lawn mowers, etc.
3.6. Film belts
Though often grouped with flat belts, they are actually a different kind. They consist of a very thin belt (0.5-15 millimeters or 100-4000 micrometres) strip of plastic and occasionally rubber. They are generally intended for low-power (10hp or 7kW), high-speed uses, allowing high efficiency (up to 98%) and long life. These are seen in business machines, printers, tape recorders, and other light-duty operations.
3.7. Timing belts
Timing belts, (also known as Toothed, Notch, Cog, or Synchronous belts) are a positive transfer belt and can track relative movement. These belts have teeth that fit into a matching toothed pulley. When correctly tensioned, they have no slippage, run at constant speed, and are often used to transfer direct motion for indexing or timing purposes (hence their name). They are often used in lieu of chains or gears, so there is less noise and a lubrication bath is not necessary. Camshafts of automobiles, miniature timing systems, and stepper motors often utilize these belts. Timing belts need the least tension of all belts, and are among the most efficient. They can bear up to 200hp (150kW) at speeds of 16,000ft/min.
Timing belts with a helical offset tooth design are available. The helical offset tooth design forms a chevron pattern and causes the teeth to engage progressively. The chevron pattern design is self-aligning. The chevron pattern design does not make the noise that some timing belts make at idiosyncratic speeds, and is more efficient at transferring power (up to 98%).
Disadvantages include a relatively high purchase cost, the need for specially fabricated toothed pulleys, less protection from overloading and jamming, and the lack of clutch action.
3.8. Specialty belts
Belts normally transmit power on the tension side of the loop. However, designs for continuously variable transmissions exist that use belts that are a series of solid metal blocks, linked together as in a chain, transmitting power on the compression side of the loop.
4. Uses of Belts
4.1. Rolling roads
Belts used for rolling roads for wind tunnels can be capable of 250km/h.
4.2. Standards for use
The open belt drive has parallel shafts rotating in the same direction, whereas the cross-belt drive also bears parallel shafts but rotate in opposite direction. The former is far more common, and the latter not appropriate for timing and standard V-belts, because the pulleys contact both the both inner and outer belt surfaces. Nonparallel shafts can be connected if the belt's center line is aligned with the center plane of the pulley. Industrial belts are usually reinforced rubber but sometimes leather types, non-leather non-reinforced belts, can only be used in light applications.
The pitch line is the line between the inner and outer surfaces that is neither subject to tension (like the outer surface) nor compression (like the inner). It is midway through the surfaces in film and flat belts and dependent on cross-sectional shape and size in timing and V-belts. Calculating pitch diameter is an engineering task and is beyond the scope of this article. The angular speed is inversely proportional to size, so the larger the one wheel, the less angular velocity, and vice versa. Actual pulley speeds tend to be 0.5–1% less than generally calculated because of belt slip and stretch. In timing belts, the inverse ratio teeth of the belt contributes to the exact measurement. The speed of the belt is:
Speed = Circumference based on pitch diameter × angular speed in rpm
5. Selection criteria
Belt drives are built under the following required conditions: speeds of and power transmitted between drive and driven unit; suitable distance between shafts; and appropriate operating conditions. The equation for power is:
power (kW) = (torque in newton-meters) × (rpm) × (2π radians)/(60 sec × 1000 W)
Factors of power adjustment include speed ratio; shaft distance (long or short); type of drive unit (electric motor, internal combustion engine); service environment (oily, wet, dusty); driven unit loads (jerky, shock, reversed); and pulley-belt arrangement (open, crossed, turned). These are found in engineering handbooks and manufacturer's literature. When corrected, the horsepower is compared to rated horsepowers of the standard belt cross sections at particular belt speeds to find a number of arrays that will perform best. Now the pulley diameters are chosen. It is generally either large diameters or large cross section that are chosen, since, as stated earlier, larger belts transmit this same power at low belt speeds as smaller belts do at high speeds. To keep the driving part at its smallest, minimum-diameter pulleys are desired. Minimum pulley diameters are limited by the elongation of the belt's outer fibers as the belt wraps around the pulleys. Small pulleys increase this elongation, greatly reducing belt life. Minimum pulley diameters are often listed with each cross section and speed, or listed separately by belt cross section. After the cheapest diameters and belt section are chosen, the belt length is computed. If endless belts are used, the desired shaft spacing may need adjusting to accommodate standard length belts. It is often more economical to use two or more juxtaposed V-belts, rather than one larger belt.
In large speed ratios or small central distances, the angle of contact between the belt and pulley may be less than 180°. If this is the case, the drive power must be further increased, according to manufacturer's tables, and the selection process repeated. This is because power capacities are based on the standard of a 180° contact angle. Smaller contact angles mean less area for the belt to obtain traction, and thus the belt carries less power.
Rope
1. Introduction
A rope is a length of fibres, twisted or braided together to improve strength for pulling and connecting. It has tensile strength but is too flexible to provide compressive strength (i.e. it can be used for pulling, but not pushing). Rope is thicker and stronger than similarly constructed cord, line, string, and twine.
2. Construction
Three-strand twisted natural fibre rope
Common materials for rope include natural fibres such as manila hemp , hemp, linen, cotton, coir, and sisal.
Synthetic fibres in use for rope-making include polypropylene, nylon, polysters and polyramids . Some ropes are constructed of mixtures of several fibres or use co-polymer fibres. Rope can also be made out of metal. Ropes have been constructed of other fibrous materials such as silk, wool and hair, but such ropes are not generally available. Rayon is a regenerated fibre used to make decorative rope.
3. Usage
Rope is of paramount importance in fields as diverse as , seafring construction, exploration, sports and communications and has been since prehistoric times. In order to fasten rope, a large number of knots have been invented for countless uses. Pulleys are used to redirect the pulling force to another direction, and may be used to create mechanical advantage, allowing multiple strands of rope to share a load and multiply the force applied to the end. Winches and capstans are machines designed to pull ropes.
4. Types of Rope
4.1. Rock climbing ropes
The modern sport of rock climbing makes extensive use of so called "dynamic" rope, which is designed to stretch under load in an elastic manner in order to absorb the energy required to arrest a person in free fall without generating forces high enough to injure them. Such ropes normally use a Kernmantle construction, as described below. "Static" ropes, used for example in caving, rappelling, and rescue applications, are designed for minimal stretch; they are not designed to arrest free falls. The UIAA, in concert with the CEN, sets climbing-rope standards and oversees testing. Any rope bearing a GUIANA or CE certification tag is fine for climbing. Despite the hundreds of thousands of falls climbers suffer every year, there are few recorded instances of a climbing rope breaking in a fall, those that do happen are often attributable to previous damage to or contamination of the rope. Climbing ropes, however, do cut easily when under load. Keeping them away from sharp rock edges is imperative.
Rock climbing ropes come with either a designation for Single, or Double(Twin) use. A single rope is the most common and it is intended to be used by itself, as a single strand. Single rope range in thickness from roughly 9mm to 11mm. Smaller ropes are lighter, but wear out faster. Double ropes are thinner ropes, usually 9mm and under, and are intended to be used as a pair. These ropes offer a greater margin or security against cutting, since it is unlikely that both ropes will be cut, but complicate belaying and leading. Double ropes are usually reserved for ice and mixed climbing, where there is need for two ropes to rappel or abseil. They are also popular among traditional climbers, and particularly in the UK.
4.2. Laid or twisted rope
Laid rope, also called twisted rope, is historically the prevalent form of rope, at least in modern western history. Common twisted rope generally consists of three strands and is normally right-laid, or given a final right-handed twist. The ISO 2 standard uses the uppercase letters S and Z to indicate the two possible directions of twist, as suggested by the direction of slant of the central portions of these two letters. The handedness of the twist is the direction of the twists as they progress away from an observer. Thus Z-twist rope is said to be right-handed, and S-twist to be left-handed.
Twisted ropes are built up in three steps. First, fibres are gathered and spun to form yarns. Member of these yarns are then twisted together to form strands. The strands are then twisted together to form the rope. The twist of the yarn is opposite to that of the strand, and that in turn is opposite to that of the rope. It is this counter-twist, introduced with each successive operation, which holds the final rope together as a stable, unified object.
Traditionally, a three strand laid rope is called a plain- or hawser-laid, a four strand rope is called shroud-laid, and a larger rope formed by counter-twisting three or more multi-strand ropes together is called cable-laid.
One property of laid rope is partial untwisting when used. This can cause spinning of suspended loads, or stretching, kinking, or hockling of the rope itself. An additional drawback of twisted construction is that every fibre is exposed to abrasion numerous times along the length of the rope. This means that the rope can degrade to numerous inch-long fibre fragments, which is not easily detected visually.
Twisted ropes have a preferred direction for coiling. Normal right-laid rope should be coiled with the sun, or clockwise, to prevent kinking. Coiling this way imparts a twist to the rope. Rope of this type must be bound at its ends by some means to prevent untwisting.
4.3. Braided rope
Braided ropes are generally made from nylon, polyster or polypropylene. Nylon is chosen for its elastic stretch properties though it has limited resistance to ultraviolet light. Polyester is about 90% as strong as nylon but stretches less under load, is more abrasion resistant, has better UV resistance, and has less change in length when wet. Polypropylene is preferred for low cost and light weight (it floats on water).
Braided ropes (and objects like garden hoses, fibre optic or coaxial cables, etc.) that have no lay, or inherent twist, will uncoil better if coiled into coils, where the twist reverses regularly and essentially cancels out.
Single braid consists of even number of strands, eight or twelve being typical, braided into a circular pattern with half of the strands going clockwise and the other half going anticlockwise. The strands can interlock with either twill or plain weave. The central void may be large or small; in the former case the term hollow braid is sometimes preferred.
Double braid, also called braid on braid, consists of an inner braid filling the central void in an outer braid, that may be of the same or different material. Often the inner braid fibre is chosen for strength while the outer braid fibre is chosen for abrasion resistance.
In solid braid the strands all travel the same direction, clockwise or anticlockwise, and alternate between forming the outside of the rope and the interior of the rope. This construction is popular for general purpose utility rope but rare in specialized high performance line.
Kernmantle rope has a core (kern) of long twisted fibres in the center, with a braided outer sheath or mantle of woven fibres. The kern provides most of the strength (about 70%), while the mantle protects the kern and determines the handling properties of the rope (how easy it is to hold, to tie knots in, and so on). In dynamic climbing line, the core fibres are usually twisted, and chopped into shorter lengths which makes the rope more stretchy. Static kernmantle ropes are made with untwisted core fibres and tighter braid, which causes them to be stiffer in addition to limiting the stretch.
4.4. Flying rope
For transmission of mechanical power over distance without electrical energy, a flying rope can be used. A wire or manila rope can be used to transmit mechanical energy from a steam engine or water wheel to a factory or pump which is located a considerable distance (10 to 100s of meters or more) from the power source. A flying rope way could be supported on poles and pulleys similar to the cable on a chair lift or aerial tramway. Transmission efficiency is generally high.
4.5. Handling rope
Rope made from hemp, cotton or nylon is generally stored in a cool dry place for proper storage. To prevent kinking it is usually coiled. To prevent fraying or unravelling, the ends of a rope are bound with twine (whipping), tape, or heat shrink tubing. The ends of plastic fibre ropes are often melted and fused solid.
If a load-bearing rope gets a sharp or sudden jolt or the rope shows signs of deteriorating, it is recommended that the rope be replaced immediately and should be discarded or only used for non-load-bearing tasks.
The average rope life-span is five years. Serious inspection should be given to line after that point.
When preparing for a climb, it is important to stack the rope on the ground or a tarp and check for any "dead-spots".
Avoid stepping on rope, as this might force tiny pieces of rock through the sheath, which can eventually deteriorate the core of the rope. Ropes may be flemished into coils on deck for safety and presentation/tidiness as shown in picture.
5. Some Other types
Plaited rope is made by braiding twisted strands, and is also called square braid. It is not as round as twisted rope and coarser to the touch. It is less prone to kinking than twisted rope and, depending on the material, very flexible and therefore easy to handle and knot. This construction exposes all fibres as well, with the same drawbacks as described above.
Brait rope is a combination of braided and plaited, a non-rotating alternative to laid three-strand ropes. Due to its excellent energy-absorption characteristics, it is often used by arborists. It is also the most popular rope for anchoring and can be used as mooring warps. This type of construction was pioneered by Yale Cordage.
CHAIN DRIVES
1. Introduction
Chain drive is a way of transmitting mechanical power from one place to another. It is often used to convey power to the wheels of a vehicle, particularly bicycle and motorcycles. It is also used in a wide variety of machines besides vehicles.
Most often, the power is conveyed by a roller chain, known as the drive chain or transmission chain, passing over a sprocket gear, with the teeth of the gear meshing with the holes in the links of the chain. The gear is turned, and this pulls the chain putting mechanical force into the system. Another type of drive chain is the Morse chain, invented by the Morse Chain Company of Ithaca, New York, USA. This has inverted teeth.
Sometimes the power is output by simply rotating the chain, which can be used to lift or drag objects. In other situations, a second gear is placed and the power is recovered by attaching shafts or hubs to this gear. Though drive chains are often simple oval loops, they can also go around corners by placing more than two gears along the chain; gears that do not put power into the system or transmit it out are generally known as idler-wheels. By varying the diameter of the input and output gears with respect to each other, the gear ratio can be altered, so that, for example, the pedals of a bicycle can spin all the way around more than once for every rotation of the gear that drives the wheels.
2. Chains versus belts
Drive chains are most often made of metal, while belts are often rubber, plastic, or other substances. Although well-made chains may prove stronger than belts, their greater mass increases drive train inertia.
Drive belts can often slip (unless they have teeth) which means that the output side may not rotate at a precise speed, and some work gets lost to the friction of the belt against its rollers. Teeth on toothed drive belts generally wear faster than links on chains, but wear on rubber or plastic belts and their teeth is often easier to observe; you can often tell a belt is wearing out and about to break more easily than a chain.
Chains are often narrower than belts, and this can make it easier to shift them to larger or smaller gears in order to vary the gear ratio. Multi-speed bicycles with derailleurs make use of this. Also, the more positive meshing of a chain can make it easier to build gears that can increase or shrink in diameter, again altering the gear ratio.
Both can be used to move objects by attaching pockets, buckets, or frames to them; chains are often used to move things vertically by holding them in frames, as in industrial toasters, while belts are good at moving things horizontally in the form of conveyor belts. It is not unusual for the systems to be used in combination; for example the rollers that drive conveyor belts are themselves often driven by drive chains.
Drive shafts are another common method used to move mechanical power around that is sometimes evaluated in comparison to chain drive; in particular shaft drive versus chain drive is a key design decision for most motorcycles. Drive shafts tend to be even tougher and more reliable than chain drive, but weigh even more (robbing more power), and impart rotational torque.
3. Use in vehicles
3.1. Bicycles
Chain drive was the main feature which differentiated the safety bicycle introduced in 1885, with its two equal-sized wheels, from the direct-drive penny-farthing or "high wheeler" type of bicycle. The popularity of the chain-driven safety bicycle brought about the demise of the penny-farthing, and is still a basic feature of bicycle design today.
3.2. Automobiles
3.2.1. Transmitting power to the wheels
Chain drive was a popular power transmission system from the earliest days of the automobile. It gained prominence as an alternative to the Système Panhard with its rigid Hotchkiss driveshaft and universal joints.
A chain drive system uses one or more roller chains to transmit power from a differential to the rear axle. This system allowed for a great deal of vertical axle movement (for example, over bumps), and was simpler to design and build than a rigid driveshaft in a workable suspension. Also, it had less unsprung weight at the rear wheels than the Hotchkiss drive, which would have had the weight of the driveshaft to carry as well, which in turn meant that the tires would last longer.
Frazer Nash were strong proponents of this system using one chain per gear selected by dog clutches. The Frazer Nash chain drive system was very effective, allowing extremely fast gear selections. The Frazer Nash (or GN) transmission system provided the basis for many "special" racing cars of the 1920s and 1930s, the most famous being Basil Davenport's Spider which held the outright record at the Shelsley Walsh Speed Hill Climb in the 1920s.
Parry-Thomus was killed during a land speed record attempt in his car 'Babs' when the chain final-drive broke, decapitating him.
The last popular chain drive automobile was the Honda S600 of the 1960s.
3.2.2. Inside motors
Internal combustion engines often use chain drive to power the timing chain used to drive overhead camshaft valvetrains. This is an area in which chain drives frequently compete directly with belt drive systems, and an excellent example of some of the differences and similarities between the two approaches. For this application, chains last longer, but are often harder to replace. Being heavier, the chain robs more power, but is also less likely to fail. The camshaft of a four stroke engine must rotate at half crankshaft speed, so some form of reduction gearing is needed and a direct drive from the crankshaft isn't possible. Alternatives to chain drives include gear trains, bevel gear and shaft drives, or toothed flexible belt drives.
Tuesday, November 16, 2010
manufacturing science
Small reaserch on
IMPORATNCE OF QUALITY IN DIFFERENT MANUFACTURING PROCESS
prepared by
Mr. Gautam saurav
Acknoledgement
I would like to express my greatest gratitude to the people who have helped & supported me throughout my project. I am grateful to my teacher Mr. SUMIT SHARMA for her continuous support for the project, from initial advice & contacts in the early stages of conceptual inception & through ongoing advice & encouragement to this day.
A special thank of mine goes to my colleague who helped me in completing the project & she exchanged her interesting ideas, thoughts & made this project easy and accurate.
I wish to thank my parents for their undivided support and interest who inspired me and encouraged me to go my own way, without whom I would be unable to complete my project. At last but not the least I want to thank my friends who appreciated me for my work and motivated me and finally to God who made all the things possible...
thank you all....................
by
Gautam Saurav
Contents
1. Impotance of quality assurance in manufacturing
1.2.Tips for seven step quality manufacturing process improvement
3.Ensure qulaity in maufacturing process
4. Computer aided quality assurance
5.Machining
6.Turning
7.Welding
Importance of Quality Assurrance in Manufacturing
Giving Quality is the process of using systems and methodologies that ensure that the manufactured products meet the required quality standards consistently. The aim of QA is to produce goods right at the first time, without any rework. Organizations, usually, have a separate department to assure the quality of their products. For this they may also use the services of the consultants.
QA is crucial for the manufacturing industry. With so much competition and such few margins, no manufacturing industry can afford to spend time and money on rework. Every activity in the industry costs money and so does rework, but customers do not pay for rework. Customers pay for the value addition by the company and if they see more valuable additions by some other company being offered at same or lower costs, they move to that company. Hence to assure good quality to customers, quality assurrance plays a significant role.
Benefits of Quality Assurrance.
Some of the benefits the organization derives from this role are:
o Improve Quality
QA professionals are involved in all critical activities of the organizations like design, manufacturing, material procurement, packaging, logistics etc. Since all the processes are being tracked and monitored properly, there are fewer chances of bad quality or non-compliance of products with respect to the requirements. These requirements could be standard requirements, customer requirements, or even legal requirements.
o Low Cost
It reduces the overall costs to the organization. When the product is right the first time, there are no rework costs, no wastage of material, no wastage of manpower, and no disruptions in the production process. There are fewer claims for warranties and guaranties. In short, the cost of poor quality goes down. All this reduces the operating costs of the organizations and hence results in increased operating profits.
o Reputation
Since the organizations are able to manufacture good quality products that are made according to the requirements of the customers, the market reputation of those organizations improves. This helps the organizations to retain the existing customers and get more business from them. At the same time this also helps them in attracting new customers. These in turn increase the revenue and profit of the organizations.
o Reduce Execution Time
The systems implemented to improve quality reduce the cycle time i.e. time taken for the execution of the orders. If the quality of products is bad then there will be more customer complaints and more production downtime. This results in huge loss of time and resources. Hence, if QA systems are implemented properly in the organization, the order execution time automatically gets reduced.
o Compliance To Standards
It ensures that the organizations meet all the standards and guidelines required for different quality management systems like ISO and other quality certifications awarded to it.
In short, to meet customer requirements effectively and consistently, it is very important for every manufacturing industry to have a QA department. This will ensure that the efforts and processes are moving in right direction so that the end product not only meets but exceeds the customers expectations.
Tips for seven step quality manufacturing process improvement
Improving quality manufacturing processes can result in decreased waste, better quality products, and an overall improvement in customer satisfaction.
The following are tips for seven step quality manufacturing process improvement. Before you start, however, you will want to develop a committee that is in charge of overseeing the steps and making sure they come to fruition. It's best to involve the whole company if possible, but in the beginning a committee can help to ensure the steps are completed and taken from beginning to end.
Step one:
The first step is to define the actual process. This is important as it provides a foundation for improving your processes. During this first step, you should name the process and its purpose, as well as its starting and ending points, inputs and outputs, and your overall requirements. It would also be a good idea to identify the customers and suppliers who will be affected by this process.
Step two:
The next step involves identifying areas of improvement that are needed. This process is usually done by selecting a random sampling of a particular product that is being manufactured. This product is then tested for a variety of things that will have an impact on the end user and consumer. This can include durability, materials, toxicity, and so forth. There are a number of ways to go about this in manufacturing. Some of the more common areas of improvement in manufacturing include disintegration of parts, loose fasteners, and so forth and should be a main focus.
Step three:
Identify potential solutions for the problems. Once the problems have been identified, it is important to then find solutions for them. Brainstorm with the committee, or consult specialists or higher ups in the manufacturing plants that can help you to arrive at the best possible solution. Additionally, you will want to get feedback from those who work on or with the process on a daily basis.
Step four
: After you have identified problem areas and then brainstormed for improvements, step four involves developing a more detailed solution for each problem area. In detailing how to solve the problem, include a budget, determine what personnel are necessary for making the improvements, conduct a projected cost analysis, and a time frame for completing the overall improvements. You will also need to determine how the rest of the manufacturing plant will be affected by this and whether it will slow production at any level.
Step five:
Put your plan into action. After a detailed plan has been made, it is time to implement it to improve your processes. Now is the time to involve everyone, from the highest levels of management in the manufacturing company
down to the workers who utilize the process.
Step six:
Evaluate. Once you have put your plan into action and have achieved the results from it, you will need to evaluate your improvement process as a whole. Ask yourselves if the process had its desired effect. Was the process successful? Did it fix the problem? Did it eliminate waste? Did you implement the improvements on time and within budget? All of these factors should be taken into consideration.
Step seven:
Continue to repeat steps two and six as often as necessary to achieve improvement within the manufacturing plant. The overall goal is to decrease the need for a committee, and instead have all members of the plant continually working to improve.
Ensure Quality in your Manufacturing Processes
Every aspect of the manufacturing process must be controlled and monitored. In order to ensure the integrity of the enterprise and to maintain quality assurance, the implementation of standards such as ISO 9000 must be pursued. This means installing efficiently designed processes throughout the operation from product development, to supply chain and shipping. By adopting a strong, process-centric culture, your company can smoothly transition from chaotic and ad hoc management systems to a smooth running operation that will increase profits.
By using our products, your company gains the accountability and consistency that will give you a cutting edge over your competition. Our tools ensure that all processes are properly understood, allowing you to increase the safety as well as the efficiency of your operations.
ISO Quality Control – Our process methodology and support for business rules and risk/control management allows effective process design that has all the appropriate checks and balances.
Utilize resources or business power will expose unused resources and allow you to take better advantage of them along the length of the process.
Manage Work Flow – Integrate your people, processes, and technology by taking advantage of our workflow engine to deliver work to where it is needed, and keep all employees up to date with the most important priorities.
Ensure transparancy – Know where resources are being used and maintain efficient work habits by planning well in advance.
Model Business Rule – Our approach to Business Process Mnagement allows your company to easily implement business rules that can be reused and easily updated along the length of your processes.
Create portable Process manuals – Our products have the ability to generate a complete output of your processes and all of the related information that is ready for print. This makes for an excellent collaborative tool, and allows your agents to share information more widely.
Implement Standard Methodologies – Avoid the need for continual trial and error in improving your agency’s operational efficiency; get a head start by taking advantage of industry standards.
Encourage Collaboration – By uniting goals and creating a common framework for your agents, they will be able to cooperate at a previously unattained level.
Computer-aided quality assurance
Computer-aided quality assurance (CAQ) is the engineering application of computers and computer controlled machines for the definition and inspection of the quality of products.
This includes:
Measuring equipment management
Goods inward inspection
Vendor rating
Attribute Chart
Statistical Process Control(SPC)
Documentation
Additional themes:
Advanced Product Quality Planning (APQP)
Failure Mode and Effect Analysis (FMEA)
Dimensional tolerance stack-up analysis using product and manufacturing information (PMI) on CAD models
Computer aided inspection with coordinate measuring machine(CMM)
Comparison of data obtained by mean of 3D scanning technologies of physical parts against CAD models
Machining
Conventional machining, one of the most important material removal methods, is a collection of material-working processes in which power-driven machine tools, such as lathes, milling machine and drill presses are used with a sharp cutting tool to mechanically cut the material to achieve the desired geometry. Machining is a part of the manufacture of almost all metal products, and it is common for other materials, such as wood and plastic, to be machined. A person who specializes in machining is called a machinist. A room, building, or company where machining is done is called a machine shop. Much of modern day machining is controlled by computers using Computer numerical control(CNC) machining. Machining can be a business, a hobby, or both.
TTtttt
Turning
Turning is the process whereby a single point cutting tool is parallel to the surface. It can be done manually, in a traditional form of lathe, which frequently requires continuous supervision by the operator, or by using a computer controlled and automated lathe which does not. This type of machine tool is referred to as having computer Numeric Control, better known as CNC. and is commonly used with many other types of machine tools besides the lathe.
When turning, a piece of material (wood, metal, plastic, or stone) is rotated and a cutting tool is traversed along 2 axes of motion to produce precise diameters and depths. Turning can be either on the outside of the cylinder or on the inside (also known as boring) to produce tubular components to various geometries. Although now quite rare, early lathes could even be used to produce complex geometric figures, even the platonic solids; although until the advent of CNC it had become unusual to use one for this purpose for the last three quarters of the twentieth century. It is said that the lathe is the only machine tool that can reproduce itself.
Welding
Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a nonconsumable tungustun electrode to produce the weld. The weld area is protected from atmospheric contamination by a shelding gas (usually an inert gas such as argon), and a filler metal is normally used, though some welds, known as autogenous welds, do not require it. A constant-current, welding power supply produces energy which is conducted across the arc through a column of highly ionized gas and metal vapors known as a plasma.
GTAW is most commonly used to weld thin sections of stainless steel and non-ferrous metals such as aluminium, magnesiumand copper alloys. The process grants the operator greater control over the weld than competing procedures such as shielded metal arc welding and gas metal arc welding, allowing for stronger, higher quality welds. However, GTAW is comparatively more complex and difficult to master, and further the more, it is significantly slower than most other welding techniques. A related process, plasma welding, uses a slightly different welding torch to create a more focused welding arc and as a result is often automated.
IMPORATNCE OF QUALITY IN DIFFERENT MANUFACTURING PROCESS
prepared by
Mr. Gautam saurav
Acknoledgement
I would like to express my greatest gratitude to the people who have helped & supported me throughout my project. I am grateful to my teacher Mr. SUMIT SHARMA for her continuous support for the project, from initial advice & contacts in the early stages of conceptual inception & through ongoing advice & encouragement to this day.
A special thank of mine goes to my colleague who helped me in completing the project & she exchanged her interesting ideas, thoughts & made this project easy and accurate.
I wish to thank my parents for their undivided support and interest who inspired me and encouraged me to go my own way, without whom I would be unable to complete my project. At last but not the least I want to thank my friends who appreciated me for my work and motivated me and finally to God who made all the things possible...
thank you all....................
by
Gautam Saurav
Contents
1. Impotance of quality assurance in manufacturing
1.2.Tips for seven step quality manufacturing process improvement
3.Ensure qulaity in maufacturing process
4. Computer aided quality assurance
5.Machining
6.Turning
7.Welding
Importance of Quality Assurrance in Manufacturing
Giving Quality is the process of using systems and methodologies that ensure that the manufactured products meet the required quality standards consistently. The aim of QA is to produce goods right at the first time, without any rework. Organizations, usually, have a separate department to assure the quality of their products. For this they may also use the services of the consultants.
QA is crucial for the manufacturing industry. With so much competition and such few margins, no manufacturing industry can afford to spend time and money on rework. Every activity in the industry costs money and so does rework, but customers do not pay for rework. Customers pay for the value addition by the company and if they see more valuable additions by some other company being offered at same or lower costs, they move to that company. Hence to assure good quality to customers, quality assurrance plays a significant role.
Benefits of Quality Assurrance.
Some of the benefits the organization derives from this role are:
o Improve Quality
QA professionals are involved in all critical activities of the organizations like design, manufacturing, material procurement, packaging, logistics etc. Since all the processes are being tracked and monitored properly, there are fewer chances of bad quality or non-compliance of products with respect to the requirements. These requirements could be standard requirements, customer requirements, or even legal requirements.
o Low Cost
It reduces the overall costs to the organization. When the product is right the first time, there are no rework costs, no wastage of material, no wastage of manpower, and no disruptions in the production process. There are fewer claims for warranties and guaranties. In short, the cost of poor quality goes down. All this reduces the operating costs of the organizations and hence results in increased operating profits.
o Reputation
Since the organizations are able to manufacture good quality products that are made according to the requirements of the customers, the market reputation of those organizations improves. This helps the organizations to retain the existing customers and get more business from them. At the same time this also helps them in attracting new customers. These in turn increase the revenue and profit of the organizations.
o Reduce Execution Time
The systems implemented to improve quality reduce the cycle time i.e. time taken for the execution of the orders. If the quality of products is bad then there will be more customer complaints and more production downtime. This results in huge loss of time and resources. Hence, if QA systems are implemented properly in the organization, the order execution time automatically gets reduced.
o Compliance To Standards
It ensures that the organizations meet all the standards and guidelines required for different quality management systems like ISO and other quality certifications awarded to it.
In short, to meet customer requirements effectively and consistently, it is very important for every manufacturing industry to have a QA department. This will ensure that the efforts and processes are moving in right direction so that the end product not only meets but exceeds the customers expectations.
Tips for seven step quality manufacturing process improvement
Improving quality manufacturing processes can result in decreased waste, better quality products, and an overall improvement in customer satisfaction.
The following are tips for seven step quality manufacturing process improvement. Before you start, however, you will want to develop a committee that is in charge of overseeing the steps and making sure they come to fruition. It's best to involve the whole company if possible, but in the beginning a committee can help to ensure the steps are completed and taken from beginning to end.
Step one:
The first step is to define the actual process. This is important as it provides a foundation for improving your processes. During this first step, you should name the process and its purpose, as well as its starting and ending points, inputs and outputs, and your overall requirements. It would also be a good idea to identify the customers and suppliers who will be affected by this process.
Step two:
The next step involves identifying areas of improvement that are needed. This process is usually done by selecting a random sampling of a particular product that is being manufactured. This product is then tested for a variety of things that will have an impact on the end user and consumer. This can include durability, materials, toxicity, and so forth. There are a number of ways to go about this in manufacturing. Some of the more common areas of improvement in manufacturing include disintegration of parts, loose fasteners, and so forth and should be a main focus.
Step three:
Identify potential solutions for the problems. Once the problems have been identified, it is important to then find solutions for them. Brainstorm with the committee, or consult specialists or higher ups in the manufacturing plants that can help you to arrive at the best possible solution. Additionally, you will want to get feedback from those who work on or with the process on a daily basis.
Step four
: After you have identified problem areas and then brainstormed for improvements, step four involves developing a more detailed solution for each problem area. In detailing how to solve the problem, include a budget, determine what personnel are necessary for making the improvements, conduct a projected cost analysis, and a time frame for completing the overall improvements. You will also need to determine how the rest of the manufacturing plant will be affected by this and whether it will slow production at any level.
Step five:
Put your plan into action. After a detailed plan has been made, it is time to implement it to improve your processes. Now is the time to involve everyone, from the highest levels of management in the manufacturing company
down to the workers who utilize the process.
Step six:
Evaluate. Once you have put your plan into action and have achieved the results from it, you will need to evaluate your improvement process as a whole. Ask yourselves if the process had its desired effect. Was the process successful? Did it fix the problem? Did it eliminate waste? Did you implement the improvements on time and within budget? All of these factors should be taken into consideration.
Step seven:
Continue to repeat steps two and six as often as necessary to achieve improvement within the manufacturing plant. The overall goal is to decrease the need for a committee, and instead have all members of the plant continually working to improve.
Ensure Quality in your Manufacturing Processes
Every aspect of the manufacturing process must be controlled and monitored. In order to ensure the integrity of the enterprise and to maintain quality assurance, the implementation of standards such as ISO 9000 must be pursued. This means installing efficiently designed processes throughout the operation from product development, to supply chain and shipping. By adopting a strong, process-centric culture, your company can smoothly transition from chaotic and ad hoc management systems to a smooth running operation that will increase profits.
By using our products, your company gains the accountability and consistency that will give you a cutting edge over your competition. Our tools ensure that all processes are properly understood, allowing you to increase the safety as well as the efficiency of your operations.
ISO Quality Control – Our process methodology and support for business rules and risk/control management allows effective process design that has all the appropriate checks and balances.
Utilize resources or business power will expose unused resources and allow you to take better advantage of them along the length of the process.
Manage Work Flow – Integrate your people, processes, and technology by taking advantage of our workflow engine to deliver work to where it is needed, and keep all employees up to date with the most important priorities.
Ensure transparancy – Know where resources are being used and maintain efficient work habits by planning well in advance.
Model Business Rule – Our approach to Business Process Mnagement allows your company to easily implement business rules that can be reused and easily updated along the length of your processes.
Create portable Process manuals – Our products have the ability to generate a complete output of your processes and all of the related information that is ready for print. This makes for an excellent collaborative tool, and allows your agents to share information more widely.
Implement Standard Methodologies – Avoid the need for continual trial and error in improving your agency’s operational efficiency; get a head start by taking advantage of industry standards.
Encourage Collaboration – By uniting goals and creating a common framework for your agents, they will be able to cooperate at a previously unattained level.
Computer-aided quality assurance
Computer-aided quality assurance (CAQ) is the engineering application of computers and computer controlled machines for the definition and inspection of the quality of products.
This includes:
Measuring equipment management
Goods inward inspection
Vendor rating
Attribute Chart
Statistical Process Control(SPC)
Documentation
Additional themes:
Advanced Product Quality Planning (APQP)
Failure Mode and Effect Analysis (FMEA)
Dimensional tolerance stack-up analysis using product and manufacturing information (PMI) on CAD models
Computer aided inspection with coordinate measuring machine(CMM)
Comparison of data obtained by mean of 3D scanning technologies of physical parts against CAD models
Machining
Conventional machining, one of the most important material removal methods, is a collection of material-working processes in which power-driven machine tools, such as lathes, milling machine and drill presses are used with a sharp cutting tool to mechanically cut the material to achieve the desired geometry. Machining is a part of the manufacture of almost all metal products, and it is common for other materials, such as wood and plastic, to be machined. A person who specializes in machining is called a machinist. A room, building, or company where machining is done is called a machine shop. Much of modern day machining is controlled by computers using Computer numerical control(CNC) machining. Machining can be a business, a hobby, or both.
TTtttt
Turning
Turning is the process whereby a single point cutting tool is parallel to the surface. It can be done manually, in a traditional form of lathe, which frequently requires continuous supervision by the operator, or by using a computer controlled and automated lathe which does not. This type of machine tool is referred to as having computer Numeric Control, better known as CNC. and is commonly used with many other types of machine tools besides the lathe.
When turning, a piece of material (wood, metal, plastic, or stone) is rotated and a cutting tool is traversed along 2 axes of motion to produce precise diameters and depths. Turning can be either on the outside of the cylinder or on the inside (also known as boring) to produce tubular components to various geometries. Although now quite rare, early lathes could even be used to produce complex geometric figures, even the platonic solids; although until the advent of CNC it had become unusual to use one for this purpose for the last three quarters of the twentieth century. It is said that the lathe is the only machine tool that can reproduce itself.
Welding
Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a nonconsumable tungustun electrode to produce the weld. The weld area is protected from atmospheric contamination by a shelding gas (usually an inert gas such as argon), and a filler metal is normally used, though some welds, known as autogenous welds, do not require it. A constant-current, welding power supply produces energy which is conducted across the arc through a column of highly ionized gas and metal vapors known as a plasma.
GTAW is most commonly used to weld thin sections of stainless steel and non-ferrous metals such as aluminium, magnesiumand copper alloys. The process grants the operator greater control over the weld than competing procedures such as shielded metal arc welding and gas metal arc welding, allowing for stronger, higher quality welds. However, GTAW is comparatively more complex and difficult to master, and further the more, it is significantly slower than most other welding techniques. A related process, plasma welding, uses a slightly different welding torch to create a more focused welding arc and as a result is often automated.
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