Time study procedure overview n n n Perform

Time study procedure - overview n n n Perform methods analysis. Identify elements. Observe one or more operators to find observed time. Give a rating to adjust observed time and find normal time. Add allowances to normal time to find standard time. Procedures attempt to reduce inaccuracies of going from the sample to the population and from the present world to the future world. ISE 311 - 23 1

Step 1: Methods analysis n Purposes: ¨ Establish a safe, productive job. ¨ Leave a permanent record of method for future use. n n n Most of effort should be in job design and productivity rather than time standards. Once the best method is established, break the job into elements. Use the following forms as needed … ISE 311 - 23 2

Forms n Flow chart ¨ product / people flow ¨ motion patterns n n Process chart Right and left hand chart Multi-activity chart Operator / Machine chart ISE 311 - 23 3

In-class exercise n Time to fill peg board – old method ¨ Follow the method given in the handout ¨ Determine the time to completely fill one board ¨ Repeat 5 times and calculate the average … n Redesign workspace and work method … (5 minutes) ISE 311 - 23 4

Step 2: Break the job into elements n Why … ¨ Makes it possible to reuse the data. ¨ Permits different ratings for different elements. ¨ Permits consistency checks. ¨ Improves methods descriptions. ¨ Makes incomplete data useful. ISE 311 - 23 5

Step 2: Break the job into elements n How … ¨ Identify n n Get a part Assemble two pieces together ¨ Define n n n complete actions, e. g. action endpoints (EP) or terminal points (TP) Easily recognizable Logical in context Example: Get part A, TP is part A at center Assemble two parts, TP is release of assembly in bin ¨ Endpoint of one action is beginning of the next ¨ Always keep manual and machine time separate ISE 311 - 23 6

Operator selection n n ISE 311 - 23 Treat the operator with dignity and respect. Try to make the sample representative of the population. Select experienced rather than inexperienced workers. Select average or typical workers. Vary the times and days of studies. 7

Timing techniques n Stopwatch ¨ Use snapback mode. ¨ Use electronic watches. ¨ Avoid using continuous mode. n Videotape ¨ Provides a permanent record of the method. ¨ Analysis can be done by person other than camera operator. ¨ Elements can be performance rated. ISE 311 - 23 8

Snapback recording ISE 311 - 23 9

Statistical approach – pg. 492 n Number of observations depends on: ¨ Accuracy desired ¨ Confidence desired ¨ Data variability n Example: A time study is being planned. A preliminary sample of 20 times is shown to have a mean of 16 seconds and a standard deviation of 0. 4 seconds. If a relative accuracy of 10% and a 95% (round to 2 ) confidence interval are desired, how many observations are required? ISE 311 - 23 10

Statistical approach – example (cont. ) n Standard deviation method: n Alternatively, use range method (see box 25. 1) ISE 311 - 23 11

Importance-of-decision approach n Number of observations depends on: ¨ Importance of accuracy of the time standard ¨ Cycle time ¨ Activity/year ¨ Cost of an inaccurate standard n See table 25. 2, pg. 493 ISE 311 - 23 12

Irregular and foreign observations n Irregular elements: operator activity that the observer did not anticipate ¨ include like other elements ¨ determine how often per unit produced ¨ example: clear hopper, change blade, etc. n Foreign elements: operator activity that is outside normal work ISE 311 - 23 13

Delays n Avoidable delays will not be included in standard. ¨ Drinking coffee ¨ Chatting with coworker n Unavoidable delays will be included in standard. ¨ Talking to supervisor about work ¨ Waiting for supplies ¨ Breaking a tool ISE 311 - 23 14

Recording technique for unusual events n Missed readings ¨ ‘M’ n Omitted elements ¨ ‘-’ n in time slot Elements out of order ¨ see n columns 6 -8, next page Unexpected elements ¨ code events (A, B, C, etc. ) ¨ explain code elsewhere in short (1 -3 word) note ISE 311 - 23 15

ISE 311 - 23 Sample time study form (fig. 25. 2, pg. 495) 16

Rating n n n Ensures that the standard is based on the method, not the operator. To improve rating accuracy, study an average operator. Studying average operators also improves worker acceptance of the standard. ISE 311 - 23 17

Normal pace n n ISE 311 - 23 Normal pace must be defined prior to observation. Define motivated productivity level (MPL) first. Acceptable productivity level is within expectancy of MPL is the work pace of a motivated, skilled, physically fit worker. 18

Motivated productivity level ISE 311 - 23 19

Rating techniques - problems n Micromotions change their proportions of the total task as the pace changes. ¨ Low-skill micromotions change less than the overall task. ¨ High-skill micromotions change more than the overall task. n Levels of methods detail Level 1: Level 2: Level 3: ISE 311 - 23 Management-controlled Management attempts to control Operator-controlled 20

Rating techniques: solutions Pace rating: Observer estimates the pace. Objective rating: n n 1. 2. 3. Observer rates the speed. Observer estimates task difficulty. Observer multiplies speed factor by difficulty factor to get pace. Improve accuracy n ¨ ¨ ¨ n ISE 311 - 23 number of observations skilled operator observer skilled at job Train raters 21

Setting allowances n n n Personal and fatigue allowances are set from tables. Delay allowances are set from delays actually occurring on the job. Delays during a time study may provide estimate for the delays to allow for the standard. ISE 311 - 23 22