The objectives of job design include productivity, safety, and quality of work life. Ergonomics is the incorporation of human factors in the design of the workplace. It relates to design of equipment, design of work methods, and the overall design of the work environment. Current practice in job design contains elements of two basic schools of thought. One might be called the efficiency school because it emphasizes a systematic, logical approach to job design; the other is called the behavioral school l because it emphasizes satisfaction of wants and needs. 2
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H K DANGI 3 Specialization http://www.baskent.edu.tr/~kilter 3
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H K DANGI 4 Behavioral Approaches to Job Design Job enlargement. Giving a worker a larger portion of the total task, by horizontal loading. (horizontal loading) Job rotation. Workers periodically exchange jobs. means having workers periodically exchange jobs. Job enrichment. Increasing responsibility for planning and coordination tasks, by vertical loading. (vertical loading) http://www.baskent.edu.tr/~kilter 4
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H K DANGI 5 Methods Analysis Selecting an Operation to Study Documenting the Current Method Analyzing the Job and Proposing New Methods Installing the Improved Method The Follow-Up Analyzing and improving methods is facilitated by the use of various charts such as flow process charts and worker-machine charts. http://www.baskent.edu.tr/~kilter 5
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H K DANGI 6 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. http://www.baskent.edu.tr/~kilter 6
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H K DANGI 7 http://www.baskent.edu.tr/~kilter 7
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H K DANGI 8 http://www.baskent.edu.tr/~kilter 8
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H K DANGI 9 Motion Study systematic study of the human motions used to perform an operation. Motion study principles The use of the human body. The arrangement and conditions of the workplace. The design of tools and equipment. http://www.baskent.edu.tr/~kilter 9
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H K DANGI 10 Working Conditions Temperature and Humidity. Ventilation. Illumination. Noise and Vibrations. Work Breaks. Safety. Ethical Issues. http://www.baskent.edu.tr/~kilter 10
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H K DANGI 11 Work Measurement standard timeis 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.
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H K DANGI 12 where n = Sample size needed z = Number of normal standard deviations needed for desired confidence s = Sample standard deviation a = Desired accuracy percentage x = Sample mean where e = Maximum acceptable errror 12
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H K DANGI 13 Example A time study analyst wants to estimate the time required to perform a certain job. A preliminary study yielded a mean of 6.4 minutes and a standard deviation of 2.1 minutes. The desired confidence is 95 percent. How many observations will he need (including those already taken) if the desired maximum error is a. ±10 percent of the sample mean? b. One-half minute? http://www.baskent.edu.tr/~kilter 13
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H K DANGI 14 h = .05 x = 3.00 s = 1.0 z = 1.96 (from Table S10.1 or Appendix I) 2 zs hx n = 2 1.96 x 1.0 .05 x 3 n = = 170.74 ≈ 171 Time Study Example Desired accuracy with 5% Confidence level = 95% Sample standard deviation = 1.0 Sample mean = 3.00
H K DANGI 16 Time Studies Define the task to be studied Divide the task into precise elements Decide how many times to measure the task Time and record element times and rating of performance
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H K DANGI 17 Sum of the times recorded to perform each element Number of observations Average observed time = Average observed time Performance rating factor Normal time = x Time Studies Compute average observed time Determine performance rating and normal time
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H K DANGI 18 Total normal time 1 - Allowance factor Standard time = Time Studies Add the normal times for each element to develop the total normal time for the task Compute the standard time
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Based on our knowledge of human energy expenditure
H K DANGI 20 Rest Allowances 1. Constant allowance (A) Personal allowance ……………... 5 (B) Basic fatigue allowance ………… 4 2. Variable allowances: (A) Standing allowance ……………… 2 (B) Abnormal position (i) Awkward (bending) ………… 2 Very awkward (lying, stretching) …………………… 7 Figure S10.1
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H K DANGI 21 Rest Allowances Use of force or muscular energy in lifting, pulling, pushing Weight lifted (pounds) 20 …………………………………… 3 40……………………………………. 9 60……………………………………. 17 Bad light: Well below recommended…. 2 Quite inadequate……………. 5 Figure S10.1
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H K DANGI 22 Rest Allowances (E) Atmospheric conditions (heat and humidity) …………… 0-10 Close attention: (i) Fine or exacting……………….. 2 (ii) Very fine or very exacting…… 5 Noise level: (i) Intermittent—loud…………….. 2 (ii) Intermittent—very loud or high-pitched………………... 5 Figure S10.1
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H K DANGI 23 Rest Allowances Mental strain: (i) Complex or wide span of attention.…………………….. 4 (ii) Very complex………………….. 8 Tediousness: (i) Tedious…………..……………… 2 (ii) Very tedious.…………………… 5 Figure S10.1
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H K DANGI 24 Normal time = (Average observed time) x (Rating factor) = (4.0)(.85) = 3.4 minutes Normal time 1 - Allowance factor Standard time = = = 3.4 1 - .13 3.4 .87 = 3.9 minutes Time Study Example Average observed time = 4.0 minutes Worker rating = 85% Allowance factor = 13%
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H K DANGI 25 Cycle Observed (in minutes) Performance Job Element 1 2 3 4 5 Rating Compose and type letter 8 10 9 21* 11 120% Type envelope address 2 3 2 1 3 105% Stuff, stamp, seal, and 2 1 5* 2 1 110% sort envelopes Time Study Example Allowance factor = 15% Delete unusual or nonrecurring observations (marked with *) Compute average times for each element Average time for A = (8 + 10 + 9 + 11)/4 = 9.5 minutes Average time for B = (2 + 3 + 2 + 1 + 3)/5 = 2.2 minutes Average time for C = (2 + 1 + 2 + 1)/4 = 1.5 minutes
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H K DANGI 26 Time Study Example Compute the normal time for each element Normal time = (Average observed time) x (Rating) Normal time for A = (9.5)(1.2) = 11.4 minutes Normal time for B = (2.2)(1.05) = 2.31 minutes Normal time for C = (1.5)(1.10) = 1.65 minutes Add the normal times to find the total normal time Total normal time = 11.40 + 2.31 + 1.65 = 15.36 minutes
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H K DANGI 27 Standard time = = = 18.07 minutes Total normal time 1 - Allowance factor 15.36 1 - .15 Time Study Example Compute the standard time for the job
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H K DANGI 28 http://www.baskent.edu.tr/~kilter 28
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