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Time Study. Summer Training Industrial Engineering Department. Work Measurement Tools. Time Study Work Sampling Standard Data Predetermined Time Systems Physiological Measures. Time Study. Establishment of Time Standards Estimates Historical records Standards. Estimates.
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Time Study Summer Training Industrial Engineering Department
Work Measurement Tools • Time Study • Work Sampling • Standard Data • Predetermined Time Systems • Physiological Measures
Time Study • Establishment of Time Standards • Estimates • Historical records • Standards
Estimates • Original method • Increasing competition requires fact rather than judgment • Unfair due to variability among estimators • Looking at a job and judging the amount of the time needed
Historical Records • Based on the record of similar, previously performed jobs • Measures time over entire job with no consideration of delays • Better than estimates (or lack of a standard)
Time Study • Establishes a standard for a given task • Measures work content, allows for fatigue, personal and unavoidable delays • Increases the efficiency of the equipment and personnel
“A Fair Days Work” • The amount of work that can be produced by a qualified employee when working at a normal pace and effectively utilizing their time where work is not restricted by process limitations
Responsibility • Notification • Proper cutting tools, lubricants, materials, feeds & speeds, knowledge of procedure • Normal pace, no introduction of new movements • Union support
Equipment • Stopwatch • Decimal minute watch – 100 divisions (.01 minute) • Provides continuousorsnapback timing • Electronic watch – accuracy of .001 second (600 times more accurate) • Provides bothcontinuousand snapback timing • Computer Assisted Electronic Stopwatch
Equipment (con’t) • Video cameras • Time study board • Time study forms (TP) • Time study Software • Training equipment
Time Study Elements • Watch operator for several cycles • Break task down into fine elements • Look for natural breakpoints using both sight and sound • Record elements in proper sequence • Do not repeat identical elements descriptions, just reference the previous #
Timing • Record only what is necessary to rebuild later (TP) • Two Methods • Snapback: Watch is reset after each breakpoint of an element • Continuous: Watch is allowed to run for the entire job being evaluated
Snapback Method • No clerical time needed to subtract from the previous observations as in continuous (TP) • Read and record Observed Time (OT) directly • Short element times are difficult to time • Possible cycle time lost during the snapback (N/A to electronic watch)
Continuous Method • Presents a complete record for the entire observation period • All delays and foreign elements are recorded • Better adapted to record short element times • Clerical work required
Figure 9-7 Continuous Study
Missed Breakpoints • Immediately mark an “M” in the W column • If operator omits an element, draw a dash (-) through the applicable space in the W column
Foreign Elements • Things that are external to the process that delay the work moving forward • Include: Supervisor interruptions, power losses, defective parts, leaving workstation, tool breakage, etc… • Occurring during an element, write A, B, C, etc…In the NT block (TP)
Number of Cycles to Record • Tabulated data (TP) • Statistical methods • Confidence • Accuracy
Ratings • Normalize the readings to the “average operator” • Can be for the entire element or individual cycles • NT=OT x R/100
Allowances • Typically about 15% • Personal interruptions • Fatigue • Unavoidable delay • Standard Time (ST) = NT (1 + allowance)
Study Calculations • Start time, Finish time, Elapsed time, Time elapsed before study (TEBS), Time elapsed after study (TEAS), Total check time, Effective time, Ineffective time, Unaccounted time, Recording error (should not exceed ~ 2%)