ISE 430
Dead Reckoning
Refers to the capability of a vehicle to follow a given route along a route in the absence of a defined pathway on the floor.
Into which of the four basic categories of part-shaping operations does powder metallurgy belong?
particulate proccessing
Production systems consist of two major components. Name and briefly define them.
(1) facilities, which consist of the factory, the equipment in the factory, and the way the equipment is organized; (2) manufacturing support systems, which are the procedures used by the company to manage production and to solve the technical and logistics problems encountered in ordering materials, moving the work through the factory, and ensuring that products meet quality standards. Product design and certain business functions are included among the manufacturing support systems.
As the number of workstation on an automated production line increases, does line efficiency (a) decrease, (b) increase, or (c) remain unaffected?
(a). Line efficiency decreases because each additional station increases the probability of a line stop.
Flow line production is associated with which one of the following layout types: (a) cellular layout, (b) fixed-position layout, (c) process layout, or (d) product layout?
(d) Product layout.
Is a Geneva mechanism used to provide linear motion or rotary motion?
A Geneva mechanism provides rotary motion.
Flow line production is usually associated with which type of layout
A U-style layout
What is a dial-indexing machine?
A dial-indexing machine is an automated system consisting of multiple workstations that process workparts attached to fixtures around the periphery of a circular worktable, and the table is indexed (rotated in fixed angular amounts) to position the parts at the stations.
What is the difference between a hoist and a crane?
A hoist is a mechanical device for lifting and lowering loads vertically, whereas a crane is a mechanical apparatus for horizontal movement of loads. A crane invariably includes one or more hoists.
What is the difference between a horizontal machining center and a vertical machining center?
A horizontal machining center has a horizontal spindle (to hold rotating cutting tools) while a vertical machining center has a vertical spindle.
What are manufacturing systems, and how are they distinguished from production systems?
A manufacturing system is a logical grouping of equipment in the factory and the worker(s) who operate(s) it. Examples include worker-machine systems, production lines, and machine cells. A production system is a larger system that includes a collection of manufacturing systems and the support systems used to manage them. A manufacturing system is a subset of the production system.
What is the difference between a processing operation and an assembly operation?
A processing operation transforms a work material from one state of completion to a more advanced state that is closer to the final desired part or product. It adds value by changing the geometry, properties, or appearance of the starting material. An assembly operation joins two or more components to create a new entity, called an assembly, subassembly, or some other term that refers to the joining process.
What is a recirculating conveyor?
A recirculating conveyor is a closed-loop conveyor that allow parts or loads to remain on the return loop for one or more revolutions.
What is a single-station automated cell?
A single station automated cell is a fully-automated machine capable of unattended operation for a time period longer than one machine cycle. A worker is not required to be at the machine except periodically to load and unload parts or otherwise tend it.
What is the difference between a single-model production line and a mixed-model production line?
A single-model production line makes products that are all identical. A mixedmodel production line makes products that have model variations characterized as soft product variety.
What are storage buffers and why are they sometimes used on a manual assembly line?
A storage buffer is a location in the production line where work units are temporarily stored. As identified in the text, the reasons to include one or more storage buffers in a production line include: (1) to accumulate work units between two stages of the line when their production rates are different; (2) to smooth production between stations with large task time variations; and (3) to permit continued operation of certain sections of the line when other sections are temporarily down for service or repair.
What is the difference between a turning center and a mill-turn center?
A turning center performs turning and related fixed tooling operations, while a mill-turn center is also capable of performing operations that use rotating cutting tools.
What is the difference between a unitized production line and a link line?
A unitized production line is an automated production line that consists of standard modules and is assembled in an appropriate configuration to satisfy the production requirements of the customer. A link line is a production line that consists of standard machine tools that are connected together by standard or special material handling devices.
What is an automatic pallet changer?
An automatic pallet changer is a part handling subsystem that is used to exchange pallet fixtures between the machine tool worktable and the load/unload position or part storage system.
Name some of the industrial applications of automated production lines.
Applications listed in the text include machining, sheet metal forming and cutting, spot welding of car bodies in final assembly plants, painting and plating operations, and assembly.
What is a conveyor?
As defined in the text, a conveyor is a mechanical apparatus for moving items or bulk materials, usually inside a facility. Conveyors are used when material must be moved in relatively large quantities between specific locations over a fixed path, which may be inthe-floor, above-the-floor, or overhead. Conveyors divide into two basic categories: (1) powered and (2) non-powered.
What is a machine cluster?
As defined in the text, a machine cluster is a collection of two or more machines producing parts or products with identical cycle times and serviced (usually loaded and unloaded) by one worker.
What is a machining center?
As defined in the text, a machining center is a machine tool capable of performing multiple machining operations on a workpart in one setup under NC program control. Operations performed on a machining center are those that use a rotating cutting tool, such as milling, drilling, reaming, and tapping.
What is a minimum rational work element?
As defined in the text, a minimum rational work element is a small amount of work that has a specific limited objective, such as adding a component to the base part or joining two components. A minimum rational work element cannot be subdivided any further without loss of practicality.
What is a pallet fixture, as the term is used in the context of an automated production line?
As defined in the text, a pallet fixture is a workholding device that is designed to (1) fixture the part in a precise location relative to its base and (2) be moved, located, and accurately clamped in position at successive workstations by the transfer system.
What is a part family?
As defined in the text, a part family is a collection of parts that are similar either because of geometric shape and size or because similar processing steps are required in their manufacture.
What does the term semi-automated station mean?
As defined in the text, a semi-automated station is a machine that is controlled by some form of program during a portion of the work cycle, and the worker's function is simply to load and unload the machine each cycle, and periodically change cutting tools.
What is a storage buffer as the term is used for an automated production line?
As defined in the text, a storage buffer is a location in a production line where parts can be collected and temporarily stored before proceeding to downstream stations
What is an automated guided vehicle system (AGVS)?
As defined in the text, an automated guided vehicle system is a material handling system that uses independently operated, self-propelled vehicles guided along defined pathways. The vehicles are powered by on-board batteries.
What is an automated production line?
As defined in the text, an automated production line consists of multiple workstations that are automated and linked together by a work handling system that transfers parts from one station to the next.
What is an automation migration strategy?
As defined in the text, an automation migration strategy is a formalized plan for evolving the manufacturing systems used to produce new products as demand grows.
What is cellular manufacturing?
As defined in the text, cellular manufacturing is an application of group technology in which dissimilar machines or processes have been aggregated into cells, each of which is dedicated to the production of a part or product family or a limited group of families.
What is computer-integrated manufacturing?
As defined in the text, computer-integrated manufacturing (CIM) denotes the pervasive use of computer systems to design the products, plan the production, control the operations, and perform the various information-processing functions needed in a manufacturing firm. True CIM involves integrating all of these functions in one system that operates throughout the enterprise
What is group technology?
As defined in the text, group technology is a manufacturing philosophy in which similar parts are identified and grouped together to take advantage of their similarities in design and production.
What is production flow analysis?
As defined in the text, production flow analysis is a method for identifying part families and associated machine groupings that uses the information contained on production route sheets rather than part drawings. Workparts with identical or similar routings are grouped into part families.
What are the three phases of a typical automation migration strategy?
As defined in the text, the three typical phases are the following: Phase 1: Manual production using single-station manned cells operating independently. Phase 2: Automated production using single-station automated cells operating independently. Phase 3: Automated integrated production using a multi-station automated system with serial operations and automated transfer of work units between stations.
What is included within the term unitizing equipment?
As defined in the text, unitizing equipment refers to the containers used to hold individual items during handling and the equipment used to load and package the containers.
What are the typical objectives when implementing cellular manufacturing?
As enumerated in the text, the objectives are to (1) shorten manufacturing lead times, by reducing setup, workpart handling, waiting times, and batch sizes; (2) reduce work-in-process inventory; (3) improve quality; (4) simplify production scheduling; and (5) reduce setup times.
What are the five enablers that are required for unattended operation of automated cells designed to produce identical parts or products?
As given in the text, the five enablers of unattended operation of automated cells designed to produce identical parts or products are the following: (1) a programmed cycle that allows the machine to perform every step of the processing or assembly cycle automatically; (2) a parts storage system and a supply of parts that permit continuous operation beyond one machine cycle; (3) automatic transfer of workparts between the storage system and the machine (automatic unloading of finished parts from the machine and loading of raw workparts to the machine); (4) periodic attention of a worker who performs the necessary machine tending functions (e.g., parts loading and unloading of the storage subsystem) for the particular processing or assembly operation; and (5) built-in safeguards that protect the system against operating under conditions that may be unsafe for humans or self-destructive or destructive to the work units being processed or assembled.
What are the additional three enablers that are required for unattended operation of automated cells designed for product variety?
As given in the text, the three enablers of unattended operation of automated cells designed for product variety are (1) a work identification system that can distinguish between the different starting work units entering the station, so that the correct processing sequence can be used for that part or product style; (2) a program downloading capability to transfer the machine cycle program corresponding to the identified part or product style; and (3) a quick setup changeover capability so that the necessary workholding devices and other tools for each part are available on demand.
Name the four major categories of material handling equipment.
As identified in the text, the four categories of material handling equipment are (1) transport equipment, (2) positioning equipment, (3) unit load formation equipment, (4) storage equipment, and (5) identification and control equipment.
What are the four functions included within the scope of manufacturing support systems?
As identified in the text, the four functions are (1) business functions, (2) product design, (3) manufacturing planning, and (4) manufacturing control.
What is the principal application of group technology in product design?
As indicated in the text, the principal application of GT in design is to implement a design retrieval system that reduces part proliferation.
Why is the production rate inherently lower on a single-station assembly system than on a multi-station assembly system?
Because all of the work elements are performed sequentially at one station in the single-station system, whereas the elements are performed simultaneously at multiple workstations in a multi-station system.
What is the key machine concept in cellular manufacturing?
Certain machine is typically more expensive and critical for operation has other machines designed around it to support.
What is the difference between combined operations and simultaneous operations?
Combined - perform more than 1 operation at a given machine (reduces # of mach) Siml - 2 or more ops done at the same time
What is the difference between consumer goods and capital goods?
Consumer goods are products that are purchased directly by consumers, such as cars, personal computers, TVs, tires, toys, and tennis rackets. Capital goods are products purchased by other companies to produce goods and supply services. Examples include commercial aircraft, mainframe computers, machine tools, railroad equipment, and construction machinery.
Why are continuous work transport systems uncommon on automated production lines?
Continuous work transport systems are uncommon on automated lines due to the difficulty in providing accurate registration between the station workheads and the continuously moving parts.
What features distinguish laser-guided vehicles from conventional AGVs?
Conventional AGVs use either imbedded guide wires in the floor or paint strips on the floor surface as the guidance technology, whereas laser-guided vehicles (LGVs) operate without continuously defined pathways. Instead, they use a combination of dead reckoning and reflective beacons located throughout the plant that can be identified by on-board laser scanners. Dead reckoning refers to the capability of the vehicle to follow a given route by counting its own wheel rotations along a specified trajectory.
Give some examples of industrial trucks used in material handling.
Examples given in the text include nonpowered trucks such as dollies and pallet trucks, and powered trucks such as walkie trucks, forklift rider trucks, and towing tractors.
Three basic types of automation are defined in the text. What is fixed automation and what are some of its features?
Fixed automation is a system in which the sequence of processing (or assembly) operations is fixed by the equipment configuration. Each operation in the sequence is usually simple, but the integration and coordination of many such operations in one piece of equipment makes the system complex. Typical features of fixed automation are (1) high initial investment for custom-engineered equipment, (2) high production rates, and (3) relatively inflexible in accommodating product variety.
What type of automation characterized by "flexibility to deal with soft product variety?"
Flexible
What is flexible automation and what are some of its features?
Flexible automation is an extension of programmable automation. A flexible automated system is capable of producing a variety of parts (or products) with virtually no time lost for changeovers from one part style to the next. There is no lost production time while reprogramming the system and altering the physical setup. Accordingly, the system can produce various mixes and schedules of parts or products instead of requiring that they be made in batches. Features of flexible automation are (1) high investment for a customengineered system, (2) continuous production of variable mixtures of products, (3) medium production rates, and (4) flexibility to deal with product design variations
What is forward sensing in AGVS terminology?
Forward sensing involves the use of one or more sensors on each vehicle to detect the presence of other vehicles and obstacles ahead on the guide path. Sensor technologies include optical and ultrasonic devices. When the on-board sensor detects an obstacle in front of it, the vehicle is programmed to stop.
Name two part design attributes
Geometry Size
What is the difference between hard product variety and soft product variety
Hard product variety is when the products differ substantially. In an assembled product, hard variety is characterized by a low proportion of common parts among the products; in many cases, there are no common parts. Soft product variety is when there are only small differences between products. There is a high proportion of common parts among assembled products whose variety is soft.
What is the difference between a hierarchical structure and a chain-type structure in a classification and coding scheme?
In a hierarchical structure, also known as a monocode, the interpretation of each successive symbol depends on the values of the preceding symbols. In a chain-type structure, also known as a polycode, the interpretation of each symbol in the sequence is always the same; it does not depend on the values of preceding symbols.
What is programmable automation and what are some of its features?
In programmable automation, the production equipment is designed with the capability to change the sequence of operations to accommodate different part or product configurations. The operation sequence is controlled by a program, which is a set of instructions coded so that they can be read and interpreted by the system. Some of the features of programmable automation are (1) high investment in general purposeequipment, (2) lost production time due to changeovers of physical setup and reprogramming, (3) lower production rates than fixed automation, (4) flexibility to deal with variations and changes in product configuration, and (5) most suitable for batch production.
What is the difference between how the largest candidate rule works and how the Kilbridge and Wester method works?
In the largest candidate rule, the algorithm begins with the work elements listed in descending order of their time values, whereas in the Kilbridge and Wester method, the algorithm operates on the work elements listed according to their precedence order in the precedence diagram.
What is forward sensing in AGVS terminology?
Involves use of sensors to detect presence of other vehicles and obstacles ahead on path
There are two conditions when group technology is most appropriate: the first is the plant currently uses traditional batch production and a process-type layout. What is the second?
Its possible to group parts into families.
What does the term line efficiency mean in production line terminology?
Line efficiency is the proportion uptime on the production line. It is the ratio of the theoretical cycle time Tc to the actual average production time Tp when downtime on the line is averaged in.
What type of production does a job shop perform?
Low production of specialized and customized products. The products are typically complex, such as experimental aircraft and special machinery.
There are three reasons listed for using a parts classification and coding scheme. The first and second are design retrieval and automated process planing. What is the third?
Machine cell design
How does material handling fit within the scope of logistics?
Material handling is concerned with internal logistics - the movement and storage of material in a facility. By contrast, external logistics is concerned with the transportation of materials between facilities by rail, truck, seaway, air transport, and/or pipelines.
Provide a definition of material handling.
Material handling is defined by the Material Handling Industry of America (MHIA) as "the movement, protection, storage and control of materials and products throughout the process of manufacture and distribution, consumption and disposal."
What is one of the two methods of traffic control in commercial AGV systems?
Onboard sensing or zone control
What is meant by the term precedence constraint?
Precedence constraints are restrictions on the order in which the work elements can be performed. Some elements must be done before others. For example, to create a threaded hole, the hole must be drilled before it can be tapped.
What are some of the differences between rail-guided vehicles and automated guided vehicles?
Rail-guided vehicles ride on tracks on the floor or overhead, whereas AGVs ride on the building floor without rails. Rail-guided vehicles are guided by the tracks, whereas AGVs are guided by imbedded wires in the floor that emit a magnetic field, or by paint strips, or other means that does not rely on rails. Rail-guided vehicles obtain their electrical power from a "third rail", whereas AGVs carry batteries as their electrical power source.
Consider a group technology approach to designing a cellular manufacturing system. One benefit of this approach is shortened manufacturing lead items. What are two specific ways in which this is accomplished?
Setup times reduced and WIP is reduced
What is the difference between simultaneous operations and integration of operations?
Siml - 2 or more ops done at the same time Integration - automate material handing between workstations to increase overall output
What do the terms starving and blocking mean?
Starving is the situation in which the assembly operator has completed the assigned task on the current work unit, but the next unit has not yet arrived at the station. The worker is thus starved for work. Blocking means that the operator has completed the assigned task on the current work unit but cannot pass the unit to the downstream station because that worker is not yet ready to receive it. The operator is therefore blocked from working.
What is meant by the term technological processing capability?
Technological processing capability of a plant (or company) is its available set of manufacturing processes. It includes not only the physical processes, but also the expertise possessed by plant personnel in these processing technologies.
What is one of the reasons (covered in chapter 1) that we would prefer manual labor in factor operations over automation?
Technologically too difficult, short production life cycle
What is the USA Principle? What does each of the letters stand for?
The USA Principle is a common sense approach to automation and process improvement projects. U means "understand the existing process," S stands for "simplify the process," and A stands for "automate the process."
15 What is the application of rank order clustering?
The application of rank order clustering in GT is grouping machines into cells based on the part-machine incidence matrix, which in turn is based on route sheets.
What is meant by the term balance efficiency?
The balance efficiency Eb is the work content time divided by the total available service time on the line. It can be computed as Eb = Twc / wTs, where Twc = work content time, min; Ts = the maximum available service time on the line (Max{Tsi}), min/cycle; and w = number of workers.
What is the composite part concept, as the term is applied in group technology?
The composite part concept is based on part families. It conceives of a hypothetical part for a given family that includes all of the design and manufacturing attributes of the family. In general, an individual part in the family will have some of the features that characterize the family, but not all of them. The composite part possesses all of the features.
What are the production conditions under which group technology and cellular manufacturing are most applicable?
The conditions identified in the text are (1) the plant currently uses traditional batch production and a process type layout, which results in much material handling effort, high inprocess inventory, and long manufacturing lead times; and (2) it is possible to group the parts into part families.
Name some of the different types of conveyors used in industry.
The conveyor types listed in the text include roller, skate wheel, belt, chain, in-floor towline, overhead trolley, and cart-on-track.
What is the difference between the cycle time Tc and the service time Ts?
The cycle time Tc is the time interval between arrivals of work units at a station, while service time Ts is the actual amount of time available at the station to perform the assigned task. The difference is the repositioning time Tr. That is, Ts = Tc - Tr.
What is a manual assembly line?
The definition given in the text is the following: A manual assembly line is a production line that consists of a sequence of workstations where assembly tasks are performed by human workers. Products are assembled as they move along the line. At each station, a portion of the total work is performed on each unit.
What are the five categories of material transport equipment commonly used to move parts and materials inside a facility?
The five categories identified in the text are (1) industrial trucks, manual and powered, (2) automated guided vehicles, (3) monorails and other rail guided vehicles, (4) conveyors, and (5) cranes and hoists.
Identify three situations in which manual labor is preferred over automation.
The five situations listed in the text are the following: (1) The task is technologically too difficult to automate. (2) Short product life cycle. (3) Customized product. (4) To cope with ups and downs in demand. (5) To reduce risk of product failure.
What are the four common GT cell configurations, as identified in the text?
The four GT cell configurations listed in the text are (1) single-machine cell, (2) group-machine cell with manual handling, (3) group-machine cell with semi-integrated handling, and (4) flexible manufacturing cell or flexible manufacturing system.
Name the four categories of part-shaping operations, based on the state of the starting work material.
The four categories are (1) solidification processes, (2) particulate processing, (3) deformation processes, and (4) material removal processes.
Name three of the four conditions under which automated production lines are appropriate.
The four conditions listed in the text are (1) high product demand, (2) stable product design, (3) long product life, and (4) multiple operations are required to produce the product.
Name three of the four conditions under which automated assembly technology should be considered.
The four conditions named in the text are (1) high product demand, so that millions of units are produced, (2) stable product design, because design changes require tooling changes in the assembly system, (3) the assembly consists of no more than a limited number of components, say around a dozen or fewer, and (4) the product is designed for automated assembly.
What are the four automated assembly system configurations listed in the text?
The four configurations are (a) in-line assembly machine, (b) dial-type assembly machine, (c) carousel assembly system, and (d) single-station assembly machine.
What are the four factors that favor the use of manual assembly lines?
The four factors listed in the text are: (1) Demand for the product is high or medium. (2) The products are identical or similar. (3) The total work to assemble the product can be divided into small work elements. (4) It is technologically impossible or economically infeasible to automate the assembly operations.
What are the four reasons given in the text that explain why manual assembly lines are so productive compared to alternative methods in which multiple workers each perform all of the tasks to assemble the product?
The four reasons are the following: (1) Specialization of labor, which asserts that when a large job is divided into small tasks and each task is assigned to one worker, the worker becomes highly proficient at performing the single task. (2) Interchangeable parts, in which each component is manufactured to sufficiently close tolerances that any part of a certain type can be selected for assembly with its mating component. (3) Work flow principle, which involves moving the work to the worker rather than vice versa. (4) Line pacing, in which workers on an assembly line must complete their assigned tasks within a certain cycle time.
Human workers will be needed in factory operations, even in the most highly automated operations. The text identifies at least four types of work for which humans will be needed. Name them.
The four types of work identified in the text are (1) equipment maintenance, (2) programming and computer operations, (3) engineering project work, and (4) plant management.
Assembly operations can be classified as permanent joining methods and mechanical assembly. What are the four types of permanent joining methods?
The joining processes are (1) welding, (2) brazing, (3) soldering, and (4) adhesive bonding.
What is the key machine concept in cellular manufacturing?
The key machine concept acknowledges that there is typically a certain machine in a cell that is more expensive to operate than the other machines or that performs certain critical operations. This machine is referred to as the key machine. It is important that the utilization of this key machine be high, even if it means that the other machines in the cell have relatively low utilizations. The other machines are referred to as supporting machines, and they should be organized in the cell to keep the key machine busy.
What is meant by the term manning level in the context of a manual assembly line?
The manning level is the number of workers per station for a single station. For the entire line, it is the total number of workers on the line divided by the number of stations.
Name some of the important performance measures for an automated assembly system.
The performance measures considered in the text include yield (proportion of assemblies produced with no defective components), production rate, proportion uptime (a.k.a. line efficiency), and unit cost per assembly.
Name six typical products that are made by automated assembly.
The products identified in the text are alarm clocks, audio tape cassettes, ball bearings, ball point pens, cigarette lighters, computer disks, electrical plugs and sockets, fuel injectors, gear boxes, light bulbs, locks, mechanical pens and pencils, printed circuit board assemblies, pumps for household appliances, small electric motors, spark plugs, video tape cassettes, and wrist watches.
What are some of the reasons why companies automate their operations?
The reasons give in the text are (1) increase labor productivity, (2) reduce labor cost, (3) mitigate the effects of labor shortages, (4) reduce or eliminate routine manual and clerical tasks, (5) improve worker safety, (6) improve product quality, (7) reduce manufacturing lead time, (8) accomplish processes that cannot be done manually, and (9) avoid the high cost of not automating.
Name three reasons why single-station manned cells are so widely used in industry.
The reasons given in the text are the following: (1) It requires the shortest amount of time to implement. (2) It usually requires the least capital. (3) Technologically, it is the easiest system to install and operate. Its maintenance requirements are usually minimal. (4) For many situations, particularly for low quantities, it results in the lowest cost per unit produced. (5) In general, it is the most flexible manufacturing system with regard to changeovers from one part or product style to the next.
The text lists ten strategies for automation and process improvement. Identify five of these strategies.
The ten strategies listed in the text are (1) specialization of operations, (2)combined operations, (3) simultaneous operations, (4) integration of operations, (5) increased flexibility, (6) improved material handling and storage, (7) on-line inspection, (8) process control and optimization, (9) plant operations control, and (10) computerintegrated manufacturing (CIM).
What are some of the features on a NC machining center used to reduce nonproductive time in the work cycle?
The text lists the following features: (1) automatic tool-changer; (2) automatic work part positioner; and (3) automatic pallet changer.
Name three reasons for including a storage buffer in an automated production line?
The text lists the following five reasons: (1) to reduce the effect of station breakdowns, (2) to provide a bank of parts to supply the line, (3) to provide a place to put the output of the line, (4) to allow for curing time or other required delay associated with processing, and (5) to smooth cycle time variations.
What are the three basic control functions that must be accomplished to operate an automated production line?
The three basic control functions are (1) sequence control to coordinate the sequence of actions of the transfer system and associated workstations, (2) safety monitoring to ensure that the production line does not operate in an unsafe condition, and (3) quality control to monitor certain quality attributes of the workparts produced on the line.
What are the three basic industry categories?
The three basic industry categories are (1) primary industries, which are those that cultivate and exploit natural resources, such as agriculture and mining; (2) secondary industries, which convert the outputs of the primary industries into products; they include manufacturing, construction, and power generation; and (3) tertiary industries, which constitute the service sector of the economy; examples include banking, retail, transportation, education, government.
Name three categories of automated guided vehicles.
The three categories are (1) driverless trains, consisting of a towing vehicle that pulls one or more trailers, (2) pallet trucks, used to move palletized loads, and (3) unit load carriers, which move unit loads.
Manufacturing systems are divided into three categories, according to worker participation. Name the three categories.
The three categories are (1) manual work systems, (2) worker-machine systems, and (3) automated systems.
Identify and briefly describe the three major categories of mechanized work transport systems used in production lines?
The three major categories of mechanized work transport systems are (1) continuous transport, which uses a continuously moving conveyor that operates at constant speed to transport work units; (2) synchronous transport, also known as intermittent transport, in which all work units are moved simultaneously between stations with a quick discontinuous motion; and (3) asynchronous transport, in which work units are moved independently rather than synchronously between stations.
What are the three methods for solving the problem of grouping parts into part families?
The three methods are (1) intuitive grouping, a.k.a. visual inspection method, (2) parts classification and coding, and (3) production flow analysis.
Considering the assembly machine as a game of chance, what are the three possible events that might occur when the feed mechanism attempts to feed the next component to the assembly work head at a given workstation in a multi-station system?
The three possible events are (1) the component is defective and causes a station jam, (2) the component is defective but does not cause a station jam, and (3) the component is not defective.
What are the three problem areas that must be considered in the analysis and design of an automated production line?
The three problem areas identified in the text are (1) line balancing - the same basic problem as in manual assembly lines; (2) processing technology - cutting tool technology, speeds and feeds, and so on; and (3) system reliability - due to the complexity of an automated production line.
To cope with product variety, three types of assembly line are described in the text. Name the three types and explain the differences between them.
The three types of assembly line are (1) single model line, in which only one product is made and there is no variation in the product; (2) batch-model line, in which eachtype of product is produced in batches and the line setup is changed over between each batch; and (3) mixed-model line, in which different models are produced simultaneously on the same line but no changeover is required between models.
What are the effects of poor quality parts, as represented by the fraction defect rate, on the performance of an automated assembly system?
The two effects given in the text are (1) jams at stations that stop the entire assembly system to adversely affect production rate, uptime proportion, and cost per unit produced; or (2) assembly of defective parts in the product to adversely affect yield of good assemblies and product cost.
The theoretical minimum number of workers on an assembly line w* is the minimum integer that is greater than the ratio of the work content time Twc divided by the cycle time Tc. Two factors are identified in the text that make it difficult to achieve this minimum value in practice. Name the two factors.
The two factors are (1) repositioning losses, in which either the worker or the work unit must be positioned at the start of each work cycle, and (2) the line balancing problem, which refers to the difficulty encountered in allocating all of the work elements in the work content time equally among workers on the line.
What are the two major tasks that a company must undertake when it implements group technology?
The two major tasks are (1) identifying the part families and (2) rearranging production machines into machine cells.
What are two reasons for the existence of partially automated production lines?
The two reasons given in the text are (1) automation is introduced gradually on an existing manual line and (2) certain manual operations are too difficult or too costly to automate.
Name the typical hardware components of a workstation parts delivery system.
The typical components are (1) hopper, (2) parts feeder, (3) selector and/or orientor, (4) feed track, and (5) escapement and placement device.
What is the unit load principle?
The unit load principle recommends that the unit load should be designed to be as large as is practical for the material handling system that will move or store it, subject to considerations of safety, convenience, and access to the materials making up the unit load.
What is manufacturing?
Two definitions are given in the text. The technological definition is the following: Manufacturing is the application of physical and chemical processes to alter the geometry, properties, and/or appearance of a given starting material to make parts or products. Manufacturing also includes the joining of multiple parts to make assembled products. The economic definition is the following: Manufacturing is the transformation of materials into items of greater value by means of one or more processing and/or assembly operations.
What is the difference between a virtual machine cell and a formal machine cell?
Virtual machine cells involve the creation of part families and the dedication of equipment to the manufacture of these part families, but without the physical rearrangement of machines into formal cells. The machines in the virtual cell remain in their original locations in the factory. Formal machine cells represent the conventional GT approach in which a group of dissimilar machines are physically relocated into a cell that is dedicated to the production of one or a limited set of part families.
What is a production system?
a production system is a collection of people, equipment, and procedures organized to perform the manufacturing operations of a company.
