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Work Measurement Establishing the time taken by a worker to carry out a specified job a a defined level of performance.

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Presentation on theme: "Work Measurement Establishing the time taken by a worker to carry out a specified job a a defined level of performance."— Presentation transcript:

1 Work Measurement Establishing the time taken by a worker to carry out a specified job a a defined level of performance

2 Purpose of Work Measurement To reduce the amount of ineffective time Provides management with a means of identifying the causes of ineffective time

3 Uses of Work Measurment To compare the efficiency of alternative work methods To balance the work of members of teams To determine the number of machines an operative can run

4 Work Standards A ‘work standard’ is the time required for a trained worker to perform a task with normal effort and skills

5 Uses of Work Standards Capacity planning Scheduling Costing Performance appraisal Motivating workers with incentives

6 Areas of Controversy Conflict between management and workers –Workers think standards too high –Management think standards too low Conflicts expensive Need achievable standards for costing, scheduling etc. Time studies dehumanising Industrial Engineering departments expensive Using work standards for piecework incentives reduces incentive to improve work methods Trade off with quality

7 Work Measurement Techniques Time study Activity sampling Predetermined motion time systems Synthesis from standard data Estimating Analytical estimating Comparative estimating

8 Time Study Select work elements Timing the elements Determine sample time Setting the work standard

9 Selecting Work Elements Obvious starting and stopping points Long enough to accurately time Should have been running smoothly for a period of time in a standard work environment Separate incidental operations from the repetetive work

10 Timing Work Elements Stopwatch Investigate single sample times that differ greatly from other timings for the same element. Don’t include ‘irregular occurencies’, use allowances.

11 We are trying to estimate the average of the true time distribution to a certain precision with a particular confidence Do a set of initial samples Use Determining Sample Size n = [( )( )] z  p t 2 n = required sample size p = precision of estimate as a proportion of true value t = mean time from sample (the select time)  = standard deviation of sample times z = number of standard deviations for desired confidence

12 Time Study Method Packaging Coffee Cups

13 Step 1: Selecting Work Elements

14 Packaging Coffee Cups Step 1: Selecting Work Elements Work Element 1.Get carton 2.Put liner in carton 3.Place cups in carton 4.Seal carton and set aside

15 Packaging Coffee Cups Step 2: Timing the Elements StandardSelect Deviation,  Time, t Work Element(minutes)(minutes) 1.Get cartons 2.Put liner in carton 3.Place cups in carton 4.Seal carton and set aside

16 Packaging Coffee Cups Step 2: Timing the Elements (10 observations) (10 observations) StandardSelect Deviation,  Time, t Work Element(minutes)(minutes) 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside

17 Packaging Coffee Cups Step 3: Determining the Sample Size n = [( )( )] z  p t 2 StandardSelectRequired Deviation,  Time, tSample Work Element(minutes)(minutes)Size 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside

18 Packaging Coffee Cups Step 3: Determining the Sample Size StandardSelectRequired Deviation,  Time, tSample Work Element(minutes)(minutes)Size 1.Get cartons Put liner in carton Place cups in carton Seal carton and set aside n = [( )( )] z  p t 2 Desired Confidence (%)z

19 Packaging Coffee Cups Step 3: Determining the Sample Size StandardSelectRequired Deviation,  Time, tSample Work Element(minutes)(minutes)Size 1.Get two carton Put liner in carton Place cups in carton Seal carton and set aside Desired Confidence (%)z  0.04 t n = [( )( )] 2

20 Packaging Coffee Cups Step 3: Determining the Sample Size StandardSelectRequired Deviation,  Time, tSample Work Element(minutes)(minutes)Size 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside  0.04 t n = [( )( )] 2

21 Packaging Coffee Cups Step 3: Determining the Sample Size StandardSelectRequired Deviation,  Time, tSample Work Element(minutes)(minutes)Size 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside  0.04 t n = [( )( )] 2

22 Packaging Coffee Cups Step 3: Determining the Sample Size StandardSelectRequired Deviation,  Time, tSample Work Element(minutes)(minutes)Size 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside n = [( )( )]

23 Packaging Coffee Cups Step 3: Determining the Sample Size StandardSelectRequired Deviation,  Time, tSample Work Element(minutes)(minutes)Size 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside n = 36

24 Packaging Coffee Cups Step 3: Determining the Sample Size StandardSelectRequired Deviation,  Time, tSample Work Element(minutes)(minutes)Size 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside n = 36

25 Packaging Coffee Cups Step 3: Determining the Sample Size StandardSelectRequired Deviation,  Time, tSample Work Element(minutes)(minutes)Size 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside n = 36

26 Packaging Coffee Cups Step 3: Determining the Sample Size StandardSelectRequired Deviation,  Time, tSample Work Element(minutes)(minutes)Size 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside  0.04 t n = [( )( )] 2

27 Packaging Coffee Cups Step 3: Determining the Sample Size StandardSelectRequired Deviation,  Time, tSample Work Element(minutes)(minutes)Size 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside  0.04 t n = [( )( )] 2

28 Packaging Coffee Cups Step 3: Determining the Sample Size StandardSelectRequired Deviation,  Time, tSample Work Element(minutes)(minutes)Size 1.Get cartons Put liner in carton Place cups in carton Seal carton and set aside  0.04 t n = [( )( )] 2

29 Packaging Coffee Cups Step 3: Determining the Sample Size StandardSelectRequired Deviation,  Time, tSample Work Element(minutes)(minutes)Size 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside  0.04 t n = [( )( )] 2

30 Packaging Coffee Cups Step 3: Determining the Sample Size StandardSelectRequired Deviation,  Time, tSample Work Element(minutes)(minutes)Size 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside

31 Need to judge the pace of the worker to produce a rating factor (RF). RF < 1 means worker going slower than standard RF > 1 means worker going faster than standard Allowances –Contingency Allowance. For legitimate and expected work or delays which are uneconomic to measure –Relaxation Allowance. To allow for physiological or psychological effects of conditions eg. 5-7% Personal 0-10%Energy Output 0-5%Noisy 0-100%Conditions Setting the Work Standard

32 Basic time (BT) in Basic Minutes (BM) is Observed Time * Rating Factor Basic Time for Cycle (BTC) is  BT Standard time is BTC + Allowances

33 Packaging Coffee Cups Step 4: Setting the Standard Work ElementtRFBT 1.Get carton 2.Put liner in carton 3.Place cups in carton 4.Seal carton and set aside

34 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside BT = t * RF

35 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside BT = t * RF

36 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside BT = 0.26 * 1.05

37 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside BT = 0.26 * 1.05

38 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside BT = 0.26 * 1.05 = 0.28 minute

39 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside BT = t * RF

40 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside BT = t * RF

41 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside BT = t * RF

42 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside BT = t * RF

43 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside Total2.18 BT = t * RF BTC =  BT

44 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside Total2.18 BT = t * RF BTC =  BT

45 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside Total2.18 ST = BTC (1 + A )

46 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside Allowance ( A ) = 15%Total2.18 ST = BTC (1 + A )

47 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside Allowance ( A ) = 15%Total2.18 ST = 2.18 ( )

48 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside Allowance ( A ) = 15%Total2.18 ST = 2.18 ( ) = 2.51 minutes/carton

49 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFBT 1.Get carton Put liner in carton Place cups in carton Seal carton and set aside Allowance ( A ) = 15%Total2.18 Standard Time2.51 ST = 2.18 ( ) = 2.51 minutes/carton

50 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtRFNT 1.Get two cartons Put liner in carton Place cups in carton Seal carton and set aside Allowance ( A ) = 15%Total2.18 Standard Time2.51

51 Packaging Coffee Cups Step 4: Setting the Standard (after 48 additional observations) (after 48 additional observations) Work ElementtFRFNT 1.Get two cartons Put liner in carton Place cups in carton Seal carton and set aside Allowance ( A ) = 15%Total2.18 Standard Time minutes/day 2.51 minutes/carton = 191 cartons/day

52 Activity Sampling A large number of instantaneous observations made over a length of time Percentage of observations in which an activity is taking place approximates proportion of total time that activity takes place

53 Activity Sampling Advantages –Can measure activities which are too impractical or costly to measure by time study –Only needs one observer –Sampling can be interrupted Disadvantages –Quicker and easier to use Work Study on jobs of short duration –Does not provide elemental detail

54 Number of Samples Confidence interval Probability that true proportion will fall within confidence interval p - ep + ep e = z p (1 - p ) n

55 Number of Samples n =  p (1 - p )  z 2 e Desired Confidence (%)z n = required sample size p = estimate of proportion time an activity takes place z = number of standard deviations for desired confidence e = maximum error allowable

56 Predetermined Motion Time System Use established timings for basic human movements to build up time for job Potentially accurate Can be used before production in place Performance ratings may not be required Time consuming Can’t use for low repeatability jobs Different part shapes

57 Predetermined Motion Time System

58 Time TMU Wt. Allowance DistanceHand inStatic MovedMotionWt. (lb)DynamicConstant (in.)ABCBUp toFactor(TMU) 3/4 or less

59 Predetermined Motion Time System Time TMU Wt. Allowance DistanceHand inStatic MovedMotionWt. (lb)DynamicConstant (in.)ABCBUp toFactor(TMU) 3/4 or less Case and Description AMove object to other hand or against stop. BMove object to approximate or indefinite location. CMove object to exact location.

60 Predetermined Motion Time System Time TMU Wt. Allowance DistanceHand inStatic MovedMotionWt. (lb)DynamicConstant (in.)ABCBUp toFactor(TMU) 3/4 or less

61 Synthesis Build up job times from previous element times from studies on other jobs Useful where new jobs made up of well understood elements

62 Estimating Estimate made by person familiar with job Least accurate of all methods


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