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Industrial Engineering
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INSY 3021Time Study
Auburn UniversitySpring 2005
Establishment of Time Standards
Estimates Historical records Standards
Estimates
Original method 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 previously performed similar jobs
Measures time over entire job, with no consideration of delays
Better than estimates (or lack of a standard)
Time Study
Develops a time standard for performing a 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 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 continuous or snapback timing Electronic watch – accuracy of .001 second
(600 times more accurate) Provides both continuous and snapback
timing
Equipment (con’t)
Computer-Assisted electronic stopwatches Video cameras Time study board Time study forms (TP) 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)
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
Continuous: Watch is allowed to run for the entire job being evaluated
Presents a complete record for the entire observation period
All delays and foreign elements are recorded Clerical work required
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)
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
Number of Cycles to Record
Tabulated data (TP) Statistical methods
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%)
Questions & Comments