Summer Training Industrial Engineering Department Time Study Summer Training Industrial Engineering Department

Work Measurement Tools Time Study Work Sampling Standard Data Predetermined Time Systems Physiological Measures Historical data provides a rough estimate of past production, IE’s are more concerned with a more scientific measurement process. From the early days of Taylor and the Gilbreths to today, IE’s have been developing and refining the procedures used to measure work. Purpose of the tools: Develop Production Schedules Determine wage payment plans Estimate manufacturing costs Baseline for estimating production increases Identify employee training needs Appraise employee performance Justify additional production capapcity

Time Study Establishment of Time Standards Estimates Historical records Standards Time study is the oldest type of work measurement performed. Technology advances have refined traditional devices, but the procedures remain the same.

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 If standards are accurately established, they can increase the efficiency of the equipment and personnel. Poorly established standards result in high costs, labor dissension, possibly failure of an enterprise.

“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 Do you see any problems? What is meant by these terms? Broad terminology, flexible Basically saying employee should give a full day’s work for the time he or she gets paid w/reasonable allowances for personal, unavoidable delays & fatigue. Pace is representative of all-day performance by experienced, cooperative employee.

Responsibility Notification Proper cutting tools, lubricants, materials, feeds & speeds, knowledge of procedure Normal pace, no introduction of new movements Union support Communication from Analyst to Supervisor to worker to union steward to ensure everyone is on the same page and knows what is going on. EXAMPLES FROM ScriptPro, EMS

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 Computer Assisted Electronic Stopwatch Figure 9.1 on page 378 shows a decimal minute watch. Mechanical watch about $150, electronic about $50 and the price is dropping. Therefore, mechanical watches are quickly disappearing.

Equipment (con’t) Video cameras Time study board Time study forms (TP) Time study Software Training equipment Video Cameras – record operators’ methods and time; also use to train new analysts Board – to hold form and stopwatch Forms – method, tools utilized, admin information Software – Datawriter (captures electronically, download to PC), Programs for PC’s and PDA’s These eliminate much of the drudgery of data entry and improves accuracy.

Figure 9.4 – Snapback Method

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 # 0.04 min is the limit for an element…..0.02 if preceding and succeeding are long. Example: finished piece hitting a container

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

This table shows how to record data for a continuous study This table shows how to record data for a continuous study. The clerical work comes in subtracting to determine element times.

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) Both avoidable delays and unavoidable delays. Examples include: … Foreign Elements enter time into W1 and W2 block. <= 0.06 min, include in the element and circle reading.

Number of Cycles to Record Tabulated data (TP) Statistical methods Confidence Accuracy Confidence – probability an interval about a sample statistic actually includes the population parameter. Accuracy – Closeness of agreement between an observed value and accepted reference value 2 ways to determine number of cycles: specify confidence and accuracy ahead of time OR collect data, choose confidence or accuracy and calculate the other. Z test versus t test (sample < 30) Work Example.

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%)

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