Work Design and Measurement Copyright ©2018 McGraw-Hill Higher Education 7-1 You should be able to: LO 7.1 LO 7.2 LO 7.3 LO 7.4 LO 7.5 LO 7.6 Explain the importance of work design Compare and contrast the two basic approaches to job design Discuss the advantages and disadvantages of standardization Describe behavioral approaches to job design Discuss the impact of working conditions on job design Compare the advantages and disadvantages of time-based and outputbased pay systems LO 7.7 Explain the purpose of methods analysis and describe how methods studies are performed LO 7.8 Describe four commonly used techniques for motion study LO 7.9 Define a standard time LO 7.10 Describe and compare time study methods and perform calculations LO 7.11 Describe work sampling and perform calculations LO 7.12 Compare stopwatch time study and work sampling Copyright ©2018 McGraw-Hill Higher Education 7-2  Job design  The act of specifying the contents and methods of jobs     What will be done in a job Who will do the job How the job will be done Where the job will be done  Importance  Organization’s are dependent on human efforts to accomplish their goals  Many job design topics are relevant to continuous and productivity improvement  Objectives  Productivity  Safety  Quality of work life LO 7.1 Copyright ©2018 McGraw-Hill Higher Education 7-3  Efficiency School  Emphasizes a systematic, logical approach to job design  A refinement of Frederick Winslow Taylor’s scientific management concepts  Behavioral School  Emphasizes satisfaction of needs and wants of employees LO 7.2 Copyright ©2018 McGraw-Hill Higher Education 7-4  Specialization  Work that concentrates on some aspect of a product or service Advantages For management: 1. Simplifies training 2. High productivity 3. Low wage costs For employees: 1. Low education and skill requirements 2. Minimum responsibility 3. Little mental effort needed Disadvantages For management: 1. Difficult to motivate quality 2. Worker dissatisfaction, possibly resulting in absenteeism, high turnover, disruptive tactics, poor attention to quality LO 7.3 For employees: 1. Monotonous work 2. Limited opportunities for advancement 3. Little control over work 4. Little opportunity for self-fulfillment Copyright ©2018 McGraw-Hill Higher Education 7-5  Job Enlargement  Giving a worker a larger portion of the total task by horizontal loading  Job Rotation  Workers periodically exchange jobs  Job Enrichment  LO 7.4 Increasing responsibility for planning and coordination tasks, by vertical loading Copyright ©2018 McGraw-Hill Higher Education 7-6  Motivation is a key factor in many aspects of work life  Influences quality and productivity  Contributes to the work environment  Trust is an important factor that affects motivation Copyright ©2018 McGraw-Hill Higher Education 7-7  Teams take a variety of forms:  Short-term team  Formed to collaborate on a topic or solve a problem  Long-term teams  Self-directed teams  Groups empowered to make certain changes in their work processes Copyright ©2018 McGraw-Hill Higher Education 7-8  Benefits of teams  Higher quality  Higher productivity  Greater worker satisfaction  Team problems  Some managers feel threatened  Conflicts between team members Copyright ©2018 McGraw-Hill Higher Education 7-9  Quality of work life affects not only workers’ overall sense of well-being and contentment, but also their productivity  Important aspects of quality of work life:  How a worker gets along with co-workers  Quality of management  Working conditions  Compensation LO 7.5 Copyright ©2018 McGraw-Hill Higher Education 7-10  It is important for organizations to develop suitable compensation plans for their employees  Compensation approaches  Time-based systems  Output-based systems  Incentive systems  Knowledge-based systems Copyright ©2018 McGraw-Hill Higher Education 7-11  Time-based system  Compensation based on time an employee has worked during the pay period  Output-based (incentive) system  Compensation based on amount of output an employee produced during the pay period Copyright ©2018 McGraw-Hill Higher Education 7-12 TIME-BASED Advantages Disadvantages OUTPUT-BASED Advantages Disadvantages Management Worker 1. 2. 3. 4. Stable labor costs Easy to administer Simple to compute pay Stable Output 1. 2. Stable pay Less pressure to produce than under output system 1. No incentive for workers to increase output 1. Extra efforts not rewarded 1. 2. Lower cost per unit Greater output 1. 2. Pay related to efforts Opportunity to earn more 1. Wage computation more difficult Need to measure output Quality may suffer Difficult to incorporate wage increases Increased problems with scheduling 1. 2. Pay fluctuates Workers may be penalized because of factors beyond their control (e.g., machine breakdown) 2. 3. 4. 5. LO 7.6 Copyright ©2018 McGraw-Hill Higher Education 7-13  Individual incentive plans  Straight piecework  Worker’s pay is a direct linear function of his or her output  Minimum wage legislation has reduced their popularity  Base rate + bonus  Worker is guaranteed a base rate, tied to an output standard, that serves as a minimum  A bonus is paid for output above the standard  Group incentive plans  Tend to stress sharing of productivity gains with employees Copyright ©2018 McGraw-Hill Higher Education 7-14  Knowledge-based pay  A pay system used by organizations to reward workers who undergo training that increases their skills  Three dimensions:  Horizontal skills  Reflect the variety of tasks the worker is capable of performing  Vertical skills  Reflect the managerial skills the worker is capable of  Depth skills  Reflect quality and productivity results Copyright ©2018 McGraw-Hill Higher Education 7-15  Many organizations used to reward managers based on output  New emphasis is being placed on other factors of performance  Customer service  Quality  Executive pay is increasingly being tied to the success of the company or division for which the executive is responsible Copyright ©2018 McGraw-Hill Higher Education 7-16  Methods Analysis  Analyzing how a job gets done  It begins with an analysis of the overall operation  It then moves from general to specific details of the job concentrating on  Workplace arrangement  Movement of workers and/or materials LO 7.7 Copyright ©2018 McGraw-Hill Higher Education 7-17  The need for methods analysis can arise from a variety of sources 1. 2. 3. 4. 5. LO 7.7 Changes in tools and equipment Changes in product design or introduction of new products Changes in materials and procedures Government regulations or contractual agreements Accidents or quality problems Copyright ©2018 McGraw-Hill Higher Education 7-18 Identify the operation to be studied, and gather relevant data 2. Discuss the job with the operator and supervisor to get their input 3. Study and document the present methods 4. Analyze the job 5. Propose new methods 6. Install the new methods 7. Follow up implementation to assure improvements have been achieved 1. LO 7.7 Copyright ©2018 McGraw-Hill Higher Education 7-19  Consider jobs that: Have a high labor content 2. Are done frequently 3. Are unsafe, tiring, unpleasant, and/or noisy 4. Are designated as problems 1.  Quality problems  Processing bottlenecks  etc. LO 7.7 Copyright ©2018 McGraw-Hill Higher Education 7-20  Flow process chart  Chart used to examine the overall sequence of an operation by focusing on movements of the operator or flow of materials LO 7.7 Copyright ©2018 McGraw-Hill Higher Education 7-21  Worker machine chart  Chart used to determine portions of a work cycle during which an operator and equipment are busy or idle LO 7.7 Copyright ©2018 McGraw-Hill Higher Education 7-22  Motion study  Systematic study of the human motions used to perform an operation  Motion Study Techniques  Motion study principles– guidelines for designing motion- efficient work procedures  Analysis of therbligs– basic elemental motions into which a job can be broken down  Micromotion study– use of motion pictures and slow motion to study motions that otherwise would be too rapid to analyze  Charts– activity or process charts, simo charts (simultaneous motions) LO 7.8 Copyright ©2018 McGraw-Hill Higher Education 7-23  In developing work methods that are motion efficient, the analyst attempts to  Eliminate unnecessary motions  Combine activities  Reduce fatigue  Improve the arrangement of the workplace  Improve the design of tools and equipment LO 7.8 Copyright ©2018 McGraw-Hill Higher Education 7-24  Work measurement is concerned with how long it should take to complete a job.  It is not concerned with either job content or how the job is to be completed since these are considered a given when considering work measurement. LO 7.9 Copyright ©2018 McGraw-Hill Higher Education 7-25  Standard time  The amount of time it should take a qualified worker to complete a specified task, working at a sustainable rate, using given methods, tools and equipment, raw material inputs, and workplace arrangement.  Commonly used work measurement techniques  Stopwatch time study  Historical times  Predetermined data  Work sampling LO 7.9 Copyright ©2018 McGraw-Hill Higher Education 7-26  Stopwatch Time Study  Used to develop a time standard based on observations of one worker taken over a number of cycles.  Standard Elemental Times  are derived from a firm’s own historical time study data.  Predetermined time standards  involve the use of published data on standard elemental times.  Work sampling  a technique for estimating the proportion of time that a worker or machine spends on various activities and idle time. LO 7.10 Copyright ©2018 McGraw-Hill Higher Education 7-27  Used to develop a time standard based on observations of one worker taken over a number of cycles.  Basic steps in a time study: 1. 2. 3. 4. LO 7.10 Define the task to be studied and inform the worker who will be studied Determine the number of cycles to observe Time the job, and rate the worker’s performance Compute the standard time Copyright ©2018 McGraw-Hill Higher Education 7-28  The number of observations to collect is a function of  Variability of the observed times  The desired level of accuracy  Desired level of confidence for the estimated job time 2 2  zs   zs  n=  or n =    ax  e where z =# of normal stddev. needed for desired confidence s = Sample standard deviation a = Desired accuracy percentage e = Maximum acceptable error LO 7.10 x = Sample mean Copyright ©2018 McGraw-Hill Higher Education 7-29 x  OT = i n where OT = Observed time x i = Sum of recorded times n = Number of observatio ns LO 7.10 Copyright ©2018 McGraw-Hill Higher Education 7-30 NT = OT  PR where NT = Normal time PR = Performanc e rating Assumes that a single performance rating has been made for the entire job LO 7.10 Copyright ©2018 McGraw-Hill Higher Education 7-31 ( NT =  x j  PR j ) where NT = Normal time x j = Average time for element j PR j = Performanc e rating for element j Assumes that performance ratings are made on an elementby-element basis LO 7.10 Copyright ©2018 McGraw-Hill Higher Education 7-32 ST = NT  AF where ST = Standard time AF = Allowance factor and AFjob = 1 + A A = Allowance percentage based on job time AFday LO 7.10 1 = 1− A A = Allowance percentage based on workday Copyright ©2018 McGraw-Hill Higher Education 7-33  Standard Elemental Times are derived from a firm’s own historical time study data.  Over time, a file of accumulated elemental times that are common to many jobs will be collected.  In time, these standard elemental times can be retrieved from the file, eliminating the need to go through a new time study to acquire them. LO 7.10 Copyright ©2018 McGraw-Hill Higher Education 7-34  Predetermined time standards involve the use of published data on standard elemental times.  Developed in the 1940s by the Methods Engineering Council.  The MTM (methods-time-measurement) tables are based on extensive research of basic elemental motions and times.  To use this approach, the analyst must divide the job into its basic elements (reach, move, turn, etc.) measure the distances involved, and rate the difficulty of the element, and then refer to the appropriate table of data to obtain the time for that element LO 7.10 Copyright ©2018 McGraw-Hill Higher Education 7-35  Work sampling is a technique for estimating the proportion of time that a worker or machine spends on various activities and the idle time.  Work sampling does not require timing an activity or involve continuous observation of the activity  Uses: 1. ratio-delay studies which concern the percentage of a worker’s time that involves unavoidable delays or the proportion of time a machine is idle. 2. analysis of non-repetitive jobs. LO 7.11 Copyright ©2018 McGraw-Hill Higher Education 7-36 pˆ (1 − pˆ ) n z = Number of standard deviations needed to achieve desired confidence pˆ = Sample proportion (the number of occurrence s divided by the sample size n = Sample size e=z 2 z n =   pˆ (1 − pˆ ) e e = maximum error percent LO 7.11 Copyright ©2018 McGraw-Hill Higher Education 7-37 Advantages 1. 2. 3. 4. 5. 6. 7. Observations are spread out over a period of time, making results less susceptible to short-term fluctuations There is little or no disruption of work Workers are less resentful Studies are less costly and less time-consuming, and the skill requirements of the analyst are much less Studies can be interrupted without affecting the results No timing device is required It is well suited for nonrepetitive tasks Disadvantages 1. 2. 3. 4. 5. 6. There is much less detail on the elements of a job Workers may alter their work patterns when they spot the observer, thereby invalidating the results In many cases, there is no record of the method used by the worker Observers may fail to adhere to a random schedule of observations It is not well suited for short, repetitive tasks Much time may be required to move from one workplace to another and back to satisfy the randomness requirement LO 7.12 Copyright ©2018 McGraw-Hill Higher Education 7-38  Success factors:  Carried out by personnel with appropriate training and background  Consistent with the goals of the organization  In written form  Understood and agreed to by both management and employees Copyright ©2018 McGraw-Hill Higher Education 7-39  It is important to make design of work systems a key element of strategy:  People are still at the heart of the business  Workers can be valuable sources of insight and creativity  It can be beneficial to focus on quality of work life and instilling pride and respect among workers  Companies are reaping gains through worker empowerment Copyright ©2018 McGraw-Hill Higher Education 7-40 Process Selection and Facility Layout Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-1 You should be able to: LO 6.1 LO 6.2 LO 6.3 LO 6.4 LO 6.5 LO 6.6 LO 6.7 LO 6.8 LO 6.9 Explain the strategic importance of process selection and the influence it has on the organization and its supply chain Name the two main factors that influence process selection Compare the four basic processing types Explain the need for management of technology List some reasons for redesign of layouts Describe product layouts and their main advantages and disadvantages Describe process layouts and their main advantages and disadvantages Solve simple line-balancing problems Develop simple process layouts Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-2  Process selection  Refers to deciding on the way production of goods or services will be organized  It has major implications for  Capacity planning  Layout of facilities  Equipment  Design of work systems LO 6.1 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-3 Forecasting Capacity Planning Product and Service Design Technological Change LO 6.1 Facilities and Equipment Layout Process Selection Work Design Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-4  Key aspects of process strategy:  Capital intensity  The mix of equipment and labor that will be used by the organization  Process flexibility  The degree to which the system can be adjusted to changes in processing requirements due to such factors as  Product and service design changes  Volume changes  Changes in technology LO 6.1 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-5 Two key questions in process selection: 1. How much variety will the process need to be able to handle? 2. How much volume will the process need to be able to handle? Job Shop Batch Repetitive LO 6.2 Continuous Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-6 Repetitive/ Assembly Job Shop Batch Description Customized goods or services Semistandardized goods or services Standardized goods or services Highly standardized Goods or services Advantages Able to handle a wide variety of work Flexibility; easy to add or change products or services Low unit cost, high volume, efficient Very efficient, very high volume Disadvantages Slow, high cost per unit, complex planning and scheduling Moderate cost per unit, moderate scheduling complexity Low flexibility, high cost of downtime Very rigid, lack of variety, costly to change, very high cost of downtime LO 6.3 Continuous Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-7  There is increasing pressure for organizations to operate sustainable production processes  According to the Lowell Center for Sustainable Production:  “Sustainable Production is the creation of goods and services using processes and systems that are: nonpolluting; conserving of energy and natural resources; economically efficient; safe and healthful for workers, communities, and consumers; and, socially and creatively rewarding for all working people.” Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-8  Process and information technology can have a major impact on costs, productivity and competitiveness:  Process technology  Methods, procedures, and equipment used to produce goods and provide services  Information technology  The science and use of computers and other electronic equipment to store, process, and send information Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-9  Process technology and information technology can have a profound impact on:  Costs  Productivity  Competitiveness LO 6.4 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-10  Automation  Machinery that has sensing and control devices that enable it to operate automatically  Fixed automation  Programmable automation  Flexible automation Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-11  Programmable automation  Involves the use of high-cost, general-purpose equipment controlled by a computer program that provides both the sequence of operations and specific details about each operation  Computer-Aided Manufacturing (CAM)  The use of computers in process control, ranging from robots to automated quality control  Numerically Controlled (N/C) Machines  Machines that perform operations by following mathematical processing instructions  Robot  A machine consisting of a mechanical arm, a power supply, and a controller Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-12  Flexible automation  Evolved from programmable automation. It uses equipment that is more customized than that of programmable automation. A key difference between the two is that flexible automation requires significantly less changeover time.  FMS (Flexible Manufacturing System)  A group of machines designed to handle intermittent processing requirements and produce a variety of similar products  CIM (Computer Integrated Manufacturing)  A system for linking a broad range of manufacturing activities through an integrated computer system Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-13  FMS  A group of machines designed to handle intermittent processing requirements and produce a variety of similar products  Have some of the benefits of automation and some of the flexibility of individual, or stand-alone, machines  Includes supervisory computer control, automatic material handling, and robots or other automated processing equipment Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-14  CIM  A system for linking a broad range of manufacturing activities through an integrated computer system  Activities include      Engineering design FMS Purchasing Order processing Production planning and control  The overall goal of CIM is to link various parts of an organization to achieve rapid response to customer orders and/or product changes, to allow rapid production and to reduce indirect labor costs Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-15  Layout  The configuration of departments, work centers, and equipment, with particular emphasis on movement of work (customers or materials) through the system  Facilities layout decisions arise when:  Designing new facilities  Re-designing existing facilities Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-16 1. Inefficient operations  High cost  Bottlenecks 2. 3. 4. 5. 6. 7. 8. Accidents or safety hazards Changes in product or service design Introduction of new products or services Changes in output volume or product mix Changes in methods or equipment Changes in environmental or other legal requirements Morale problems LO 6.5 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-17  Basic objective  Facilitate a smooth flow of work, material, and information through the system  Supporting objectives 1. 2. 3. 4. 5. 6. 7. LO 6.5 Facilitate product or service quality Use workers and space efficiently Avoid bottlenecks Minimize material handling costs Eliminate unnecessary movement of workers or material Minimize production time or customer service time Design for safety Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-18  Product layouts  Process layouts  Fixed-position layout  Combination layouts Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-19  Product layout  Layout that uses standardized processing operations to achieve smooth, rapid, high-volume flow Raw materials or customer Material and/or labor Station 1 Material and/or labor Station 2 Material and/or labor Station 3 Station 4 Finished item Material and/or labor Used for Repetitive Processing Repetitive or Continuous LO 6.6 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-20 Advantages Disadvantages  High rate of output  Creates dull, repetitive jobs  Low unit cost  Poorly skilled workers may not  Labor specialization maintain equipment or quality  Low material handling cost per unit of output  High utilization of labor and equipment  Established routing and scheduling  Routine accounting, purchasing, and inventory control  Fairly inflexible to changes in volume or product or process design  Highly susceptible to shutdowns  Preventive maintenance, capacity for quick repair and spare-parts inventories are necessary expenses  Individual incentive plans are impractical LO 6.6 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-21  Process layouts  Layouts that can handle varied processing requirements LO 6.7 Dept. A Dept. C Dept. E Dept. B Dept. D Dept. F Used for Intermittent processing Job Shop or Batch Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-22 Advantages Disadvantages  Can handle a variety of processing  In-process inventories can be high requirements  Not particularly vulnerable to equipment failures  General-purpose equipment is often less costly and easier and less costly to maintain  It is possible to use individual incentive systems  Routing and scheduling pose continual challenges  Equipment utilization rates are low  Material handling is slow and inefficient  Reduced spans of supervision  Special attention necessary for each product or customer  Accounting, inventory control, and purchasing are more involved LO 6.7 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-23  Fixed position layout  Layout in which the product or project remains stationary, and workers, materials, and equipment are moved as needed Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-24  Some operational environments use a combination of the three basic layout types:  Hospitals  Supermarket  Shipyards  Some organizations are moving away from process layouts in an effort to capture the benefits of product layouts  Cellular manufacturing  Flexible manufacturing systems Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-25  Service layouts can be categorized as: product, process, or fixed position  Service layout requirements are somewhat different due to such factors as:  Degree of customer contact  Degree of customization  Common service layouts:  Warehouse and storage layouts  Retail layouts  Office layouts Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-26  Cellular production  Layout in which workstations are grouped into a cell that can process items that have similar processing requirements  Groupings are determined by the operations needed to perform the work for a set of similar items, part families, that require similar processing  The cells become, in effect, miniature versions of product layouts Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-27  Group technology  The grouping into part families of items with similar design or manufacturing characteristics  Design characteristics:  Size  Shape  Function  Manufacturing or processing characteristics  Type of operations required  Sequence of operations required  Requires a systematic analysis of parts to identify the part families Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-28  Two key factors:  Customer contact  Degree of customization  Layouts:  Warehouse and storage layouts  Retail layouts  Office layouts Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-29  The goal of a product layout is to arrange workers or machines in the sequence that operations need to be performed LO 6.8 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-30  Line balancing  The process of assigning tasks to workstations in such a way that the workstations have approximately equal time requirements  Goal:  Obtain task grouping that represent approximately equal time requirements since this minimizes idle time along the line and results in a high utilization of equipment and labor  Why is line balancing important? 1. It allows us to use labor and equipment more efficiently 2. To avoid fairness issues that arise when one workstation must work harder than another LO 6.8 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-31  Cycle time  The maximum time allowed at each workstation to complete its set of tasks on a unit  Cycle time also establishes the output rate of a line Operating time per day Cycle time = Desired output rate Operating time per day Output rate = Cycle time LO 6.8 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-32  The required number of workstations is a function of  Desired output rate  Our ability to combine tasks into a workstation  Theoretical minimum number of stations N min = t Cycle time where N min = theoretica l minimum number of stations  t = Sum of task time s LO 6.8 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-33  Precedence diagram  A diagram that shows elemental tasks and their precedence requirements LO 6.8 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-34  Some heuristic (intuitive) rules:  Assign tasks in order of most following tasks  Count the number of tasks that follow  Assign tasks in order of greatest positional weight  LO 6.8 Positional weight is the sum of each task’s time and the times of all following tasks Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-35  Balance delay (percentage of idle time)  Percentage of idle time of a line Balance Delay = Idle time per cycle 100 N actual  Cycle time where N actual = Actual number of stations  Efficiency  Percentage of busy time of a line Efficiency = 100% - Balance Delay LO 6.8 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-36  The main issue in designing process layouts concerns the relative placement of the departments  Measuring effectiveness  A major objective in designing process layouts is to minimize transportation cost, distance, or time LO 6.9 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-37  In designing process layouts, the following information is required: 1. 2. 3. 4. 5. 6. LO 6.9 A list of departments to be arranged and their dimensions A projection of future work flows between the pairs of work centers The distance between locations and the cost per unit of distance to move loads between them The amount of money to be invested in the layout A list of any special considerations The location of key utilities, access and exit points, etc. Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-38 Distance between locations in meters To From A A B C 20 40 B 30 C Interdepartmental work flows (loads per day) To From 1 1 2 2 3 30 170 100 3 LO 6.9 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-39 30 1 170 A 100 2 B C Dept. Loads Location Distance (meters) Load Distance Score 1 to 2 170 A to B 20 170 x 20 = 3,400 1 to 3 30 A to C 40 30 x 40 = 1,200 2 to 3 100 B to C 30 100 x 30 = 3,000 Total LO 6.9 3 7,600 Copyright ©2018 McGraw-Hill Higher Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education 6-40
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