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Om3

  1. 1. H K DANGI<br />1<br />OPERATIONS MANAGEMENT Lecture 3<br />Hamendra Dangi <br />hkdangi@fms.edu<br />9968316938<br />
  2. 2. H K DANGI<br />2<br />Job Design<br /> The act of specifying the contents and methods of jobs. <br /> Job designers focus on<br /><ul><li>what will be done in a job,
  3. 3. who will do the job,
  4. 4. how the job will be done, and
  5. 5. where the job will be done. </li></ul> The objectives of job design include productivity, safety, and quality of work life.<br />Ergonomics is the incorporation of human factors in the design of the workplace.<br /> It relates to design of equipment, design of work methods, and the overall design <br /> of the work environment.<br /> Current practice in job design contains elements of two basic schools of thought.<br /> One might be called the efficiency school because it emphasizes a systematic,<br /> logical approach to job design; the other is called the behavioral school<br /> l because it emphasizes satisfaction of wants and needs.<br />2<br />
  6. 6. H K DANGI<br />3<br />Specialization<br />http://www.baskent.edu.tr/~kilter<br />3<br />
  7. 7. H K DANGI<br />4<br />Behavioral Approaches to Job Design<br /> Job enlargement. Giving a worker a larger portion of the total task, by horizontal loading. (horizontal loading)<br /> Job rotation. Workers periodically exchange jobs. means having workers periodically exchange jobs. <br /> Job enrichment. Increasing responsibility for planning and coordination tasks, by vertical loading. (vertical loading)<br />http://www.baskent.edu.tr/~kilter<br />4<br />
  8. 8. H K DANGI<br />5<br />Methods Analysis<br />Selecting an Operation to Study<br />Documenting the Current Method<br />Analyzing the Job and Proposing New Methods<br />Installing the Improved Method<br />The Follow-Up<br />Analyzing and improving methods is facilitated by the use of various charts<br /> such as flow process charts and worker-machine charts.<br />http://www.baskent.edu.tr/~kilter<br />5<br />
  9. 9. H K DANGI<br />6<br />Flow process chartsare used to review and critically examine the overall sequence of an operation by focusing on the movements of the operator or the flow of materials.<br />http://www.baskent.edu.tr/~kilter<br />6<br />
  10. 10. H K DANGI<br />7<br />http://www.baskent.edu.tr/~kilter<br />7<br />
  11. 11. H K DANGI<br />8<br />http://www.baskent.edu.tr/~kilter<br />8<br />
  12. 12. H K DANGI<br />9<br />Motion Study<br />systematic study of the human motions used to perform an operation.<br />Motion study principles <br />The use of the human body. <br />The arrangement and conditions of the workplace. <br />The design of tools and equipment.<br />http://www.baskent.edu.tr/~kilter<br />9<br />
  13. 13. H K DANGI<br />10<br />Working Conditions<br />Temperature and Humidity.  <br />Ventilation.   <br />Illumination.    <br />Noise and Vibrations. <br />Work Breaks. <br />Safety. <br />Ethical Issues. <br />http://www.baskent.edu.tr/~kilter<br />10<br />
  14. 14. H K DANGI<br />11<br />Work Measurement<br />standard timeis the amount of time it should take a qualified worker to complete<br /> a specified task, working at a sustainable rate, using given methods, tools and<br /> equipment, raw material inputs, and workplace arrangement.<br /><ul><li>stopwatch time study
  15. 15. historical times
  16. 16. predetermined data
  17. 17. work sampling</li></ul>http://www.baskent.edu.tr/~kilter<br />11<br />
  18. 18. H K DANGI<br />12<br />where<br /> n = Sample size needed<br /> z = Number of normal standard deviations needed for desired confidence<br /> s = Sample standard deviation<br /> a = Desired accuracy percentage<br /> x = Sample mean<br />where<br /> e = Maximum acceptable errror<br />12<br />
  19. 19. H K DANGI<br />13<br />Example<br />A time study analyst wants to estimate the time required to perform a certain job.<br /> A preliminary study yielded a mean of 6.4 minutes and a standard deviation of<br /> 2.1 minutes. The desired confidence is 95 percent. How many observations will <br />he need (including those already taken) if the desired maximum error is<br />a. ±10 percent of the sample mean?<br />b. One-half minute?<br />http://www.baskent.edu.tr/~kilter<br />13<br />
  20. 20. H K DANGI<br />14<br />h = .05 x = 3.00 s = 1.0<br />z = 1.96 (from Table S10.1 or Appendix I)<br />2<br />zs<br />hx<br />n = <br />2<br />1.96 x 1.0<br />.05 x 3<br />n = = 170.74 ≈ 171<br />Time Study Example<br />Desired accuracy with 5%<br />Confidence level = 95%<br />Sample standard deviation = 1.0<br />Sample mean = 3.00<br />
  21. 21. H K DANGI<br />15<br />Time Studies<br /><ul><li>Involves timing a sample of a worker’s performance and using it to set a standard
  22. 22. Requires trained and experienced observers
  23. 23. Cannot be set before the work is performed</li></li></ul><li>H K DANGI<br />16<br />Time Studies<br />Define the task to be studied<br />Divide the task into precise elements<br />Decide how many times to measure the task<br />Time and record element times and rating of performance<br />
  24. 24. H K DANGI<br />17<br />Sum of the times recorded to perform each element<br />Number of observations<br />Average observed time<br />=<br />Average observed time<br />Performance rating factor<br />Normal time = x<br />Time Studies<br />Compute average observed time<br />Determine performance rating and normal time<br />
  25. 25. H K DANGI<br />18<br />Total normal time<br />1 - Allowance factor<br />Standard time =<br />Time Studies<br />Add the normal times for each element to develop the total normal time for the task<br />Compute the standard time<br />
  26. 26. H K DANGI<br />19<br />Rest Allowances<br /><ul><li>Personal time allowance
  27. 27. 4% - 7% of total time for use of restroom, water fountain, etc.
  28. 28. Delay allowance
  29. 29. Based upon actual delays that occur
  30. 30. Fatigue allowance
  31. 31. Based on our knowledge of human energy expenditure</li></li></ul><li>H K DANGI<br />20<br />Rest Allowances<br />1. Constant allowance<br />(A) Personal allowance ……………... 5<br />(B) Basic fatigue allowance ………… 4<br />2. Variable allowances:<br />(A) Standing allowance ……………… 2<br />(B) Abnormal position<br />(i) Awkward (bending) ………… 2<br />Very awkward (lying, stretching) …………………… 7<br />Figure S10.1<br />
  32. 32. H K DANGI<br />21<br />Rest Allowances<br />Use of force or muscular energy in lifting, pulling, pushing<br /> Weight lifted (pounds)<br /> 20 …………………………………… 3<br /> 40……………………………………. 9<br /> 60……………………………………. 17<br />Bad light:<br />Well below recommended…. 2<br /> Quite inadequate……………. 5<br />Figure S10.1<br />
  33. 33. H K DANGI<br />22<br />Rest Allowances<br />(E) Atmospheric conditions (heat and humidity) …………… 0-10<br />Close attention:<br /> (i) Fine or exacting……………….. 2<br /> (ii) Very fine or very exacting…… 5<br />Noise level:<br /> (i) Intermittent—loud…………….. 2<br /> (ii) Intermittent—very loud or high-pitched………………... 5<br />Figure S10.1<br />
  34. 34. H K DANGI<br />23<br />Rest Allowances<br />Mental strain:<br /> (i) Complex or wide span of attention.…………………….. 4<br /> (ii) Very complex………………….. 8<br />Tediousness:<br /> (i) Tedious…………..……………… 2<br /> (ii) Very tedious.…………………… 5<br />Figure S10.1<br />
  35. 35. H K DANGI<br />24<br />Normal time = (Average observed time) x (Rating factor)<br />= (4.0)(.85)<br />= 3.4 minutes<br />Normal time<br />1 - Allowance factor<br />Standard time = = =<br />3.4<br />1 - .13<br />3.4<br />.87<br />= 3.9 minutes<br />Time Study Example<br />Average observed time = 4.0 minutes<br />Worker rating = 85%<br />Allowance factor = 13%<br />
  36. 36. H K DANGI<br />25<br />Cycle Observed (in minutes)<br /> Performance<br /> Job Element 1 2 3 4 5 Rating<br />Compose and type letter 8 10 9 21* 11 120%<br />Type envelope address 2 3 2 1 3 105%<br />Stuff, stamp, seal, and 2 1 5* 2 1 110% sort envelopes<br />Time Study Example<br />Allowance factor = 15%<br />Delete unusual or nonrecurring observations (marked with *)<br />Compute average times for each element<br />Average time for A = (8 + 10 + 9 + 11)/4 = 9.5 minutes<br />Average time for B = (2 + 3 + 2 + 1 + 3)/5 = 2.2 minutes<br />Average time for C = (2 + 1 + 2 + 1)/4 = 1.5 minutes<br />
  37. 37. H K DANGI<br />26<br />Time Study Example<br />Compute the normal time for each element<br />Normal time = (Average observed time) x (Rating)<br />Normal time for A = (9.5)(1.2) = 11.4 minutes<br />Normal time for B = (2.2)(1.05) = 2.31 minutes<br />Normal time for C = (1.5)(1.10) = 1.65 minutes<br />Add the normal times to find the total normal time<br />Total normal time = 11.40 + 2.31 + 1.65 = 15.36 minutes<br />
  38. 38. H K DANGI<br />27<br />Standard time =<br />= = 18.07 minutes<br />Total normal time<br />1 - Allowance factor<br />15.36<br />1 - .15<br />Time Study Example<br />Compute the standard time for the job<br />
  39. 39. H K DANGI<br />28<br />http://www.baskent.edu.tr/~kilter<br />28<br />

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