Time Study and Work Measurement PDF

Time Study and Work Measurement Chapters: 12. Introduction to Work Measurement Part III 13. Direct Time Study 14. Predetermined Motion Time Systems 15. Standard Data Systems 16. Work Sampling 17. Computerized Work Measurement and...

Time Study and Work Measurement Chapters: 12. Introduction to Work Measurement Part III 13. Direct Time Study 14. Predetermined Motion Time Systems 15. Standard Data Systems 16. Work Sampling 17. Computerized Work Measurement and Standard Maintenance 18. Economic Justification and Applications of Time Standards 19. Learning Curves Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Introduction to Work Measurement Sections: 1. Time Standards and How They Are Chapter 12 Determined 2. Prerequisites for Valid Time Standards 3. Allowances in Time Standards 4. Accuracy, Precision, and Speed of Application in Work Measurement Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Time Is Important  Most workers are paid for their time on the job  The labor content (cost of labor time) is often a major factor in the total cost of a product or service  For any organization, it is important to know how much time will be required to accomplish a given amount of work Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Some Definitions  Work measurement – evaluation of a task in terms of the time that should be allowed by an average worker to perform the task  Standard time – amount of time that should be allowed for an average worker to process one work unit using the standard method and working at normal pace  Time study – all the ways in which time is analyzed in work situations Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. When Are Time Standards Beneficial?  Characteristics of industrial situations in which time standards would be beneficial  Low productivity  Repeat orders  Long production runs  Repetitive work cycles  Short cycle times Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Functions of Time Standards  They define a “fair day’s work”  They provide a means to convert workload into staffing and equipment needs  They allow alternative methods to be compared objectively  They provide a basis for wage incentives and evaluation of worker performance  They provide time data for:  Production planning and scheduling  Cost estimating  Material requirements planning Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. Methods to Determine Time Standards Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Work Measurement Techniques  Direct time study (DTS)  Predetermined motion time system (PMTS)  Performance rating is not required  Can be applied to determine the time standard for a task before production  Standard data systems (SDS)  Work sampling Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. Task Hierarchy & Work Measurement Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Computerized Work Measurement  Facilitates collection of data  Performs routine computations  Organizes time standards files and databases  Retrieves data in predetermined motion time systems and standard data systems  Assists in the preparation of the documentation  Methods descriptions  Reports 1-Panasonic Guided Manual Assembly English 2-Zero Errors in Manual Assembly and Packaging 3-Manual assembly Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. Prerequisites for Valid Time Standards Factors that must be standardized before a time standard can be set Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Average Worker A worker who is representative of the persons who usually perform tasks similar to the task being measured  If the work is performed mostly by men, then the average worker is male  If the work is performed mostly by women, then the average worker is female Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Standard Performance A pace of working that can be maintained by an average worker throughout an entire work shift without harmful effects on the worker’s health or physical well-being  The work shift includes periodic rest breaks and occasional interruptions are experienced by the worker  Benchmarks of standard performance:  Walking at 3 miles/hr on level flat ground  Dealing four hands of cards from a 52 card deck in exactly 30 sec Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Distribution of Worker Performance Worker performance is expressed in terms of daily output Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  More on Standard Performance  Standard performance is commonly defined to be a pace that can be readily attained by the majority of workers  A typical policy is to define standard performance so that an average worker is able to work at a pace that is 130% of that pace  Thus, most workers are able to easily achieve standard performance Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  How a Standard Time is Defined Distribution of worker performance, indicating how standard time is defined so that it can be readily achieved by most workers Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Standard Method  Must include all of the details on how the task is performed, including:  Procedure - hand and body motions  Tools  Equipment  Workplace layout  Irregular work  Working conditions  Setup Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Standard Work Units  The time needed to process the work unit depends on its starting condition  Therefore this condition must be specified  If the actual condition deviates from the specification, then extra time may be required to accomplish the task  Exactly what changes are made in the work unit by the task?  What is the final state of the completed work unit? Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Allowances in Time Standards  Normal time is adjusted by an allowance factor Apfd to obtain the standard time  Purpose of allowance factor is to compensate for lost time due to work interruptions and other reasons  Standard time: Tstd = Tn(1 + Apfd) where pfd = personal time, fatigue, and delays Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Reasons for Lost Time at Work Work-related interruptions Non-work-related interruptions  Machine breakdowns  Personal needs (e.g.,  Waiting for materials or restroom breaks) parts  Talking to co-workers about  Receiving instructions from matters unrelated to work foreman  Lunch break  Talking to co-workers about  Smoke break work-related matters  Beverage break  Rest breaks for fatigue  Personal telephone call  Cleaning up at end of shift Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  How to Allow for Lost Time  Two approaches used by companies: 1. Scheduled rest breaks during the shift  Typical - one 15-minute break in mid- morning and another in mid-afternoon 2. A PFD allowance is added to the normal time This allows the worker to take a break on his/her own time Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  PFD Allowance  Personal time  Rest room breaks, phone calls, water fountain stops, cigarette breaks (5% typical)  Fatigue  Rest allowance to overcome fatigue due to work-related stresses and conditions (5% or more)  Delays  Machine breakdowns, foreman instructions (5% typical) Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Other Types of Allowances  Contingency Allowance  Additional allowance due to a problem with the task (e.g., raw material problem ) - not greater than 5%  Temporary basis – solve the underlying problem  Policy allowance  Machine allowance (set by company policy)  Tstd= Tnw(1+Apfd)+Tm(1+Am)  Training allowance – for teaching new workers  Learning allowance – learning a new task Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Contingency Allowances Problem area Problems and examples Materials or Starting materials or parts are out of specification, and extra time is parts needed to correct the nonconformance (e.g., oversized casting that requires an extra machining pass or slower feed rate). Process Manufacturing process is not in statistical control (Section 10.2), and additional time is required to inspect every piece rather than inspect on a sampling basis. Equipment Equipment is malfunctioning or breaking down more frequently than what is provided by the unavoidable delay factor, and additional time is needed to compensate the worker to make adjustments, lubricate the machine more frequently, or other extra task(s) not included in the standard time. Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Determining Time Standards  The average observed time for a repetitive work cycle in a direct time study was 3.27 min. The worker was performance rated by the analyst at 90%. The company uses a PFD allowance factor of 13%. What is the standard time for this task?  Solution: Normal time Tn = 3.27(0.90) = 2.943 min  Standard time Tstd = 2.943(1 + 0.13) = 3.326 min Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. Use of Machine Allowance in a Wage Incentive Plan  A wage incentive plan pays workers a daily wage at a rate of $15.00/hr multiplied by the number of standard hours accomplished during the shift. One worker-machine task in the plant includes worker-paced elements totaling a normal time of 1.00 min and machine-paced elements with a time of 3.00 min. The PFD allowance is 15%. Determine the standard time for the task given that  (a) Am=0  (b) Am=30%  (c) what does a worker earn for the day under each policy if he\ she produces 115 parts that days? Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Measurement A procedure in which an unknown quantity is compared to a known standard, using an accepted and consistent system of units  Important attributes of a measurement system:  Accuracy  Precision  Speed of response  Work measurement is a measurement process Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Accuracy and Precision  Accuracy  Freedom from systematic errors, which are positive or negative deviations from the true value that are consistent from measurement to measurement  Precision  Repeatability of the measurement system  Plus or minus three standard deviations often used as a benchmark Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. Measurement Accuracy vs. Precision Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Accuracy in Work Measurement  Accuracy is concerned with closeness to the true value  But what is the true value of a task time?  Measurement is a procedure in which an unknown quantity is compared with a known standard  But the known standard in work measurement is the definition of standard performance used by the company  The standard is not based on time Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Precision in Work Measurement  Precision is concerned with the expected variability within a single time study  Precision of a time standard is determined at a certain reliability or confidence level  For example, the standard time for a task is 4.00 min, and we are 95% confident that the actual time is within 5% of that time  Related term: Consistency – concerned with variations in standard time values among different time study analysts Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. Relative Accuracy of Time Standards Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Engineered Standards  Time standards that are based on measured time values that have been adjusted for worker performance  Some effort has been made to determine best method to accomplish the task Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.  Application Speed Ratio  Speed of application – how much time is required to determine the time standard for a given task  Varies for different work measurement techniques  Application speed ratio = ratio of the time required to set the standard divided by the value of the time standard itself  Typical values = 100 to 250 Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. Relative Application Speed Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7. ©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.