Time study, Steps in making a time study, Breaking the job into elements, Sample size, Recommended cycle for time study, Stop-watch procedure

Time study

Recording the times of performing a certain specific job or its elements carried out under specified conditions, and analyzing the data so as to obtain the time necessary for an operator to carry it out at a defined rate of performance

Equipment required for time study

• A stop-watch (mechanical and electronic)
• A study board (placing the time study forms)
• Time study forms (recording of substantial amounts of data)

Selecting the job

• The job in question is a new one, not previously carried out.
• Change in material or method and a new time standard is required.
• Complaint has been received about the time standard for an operation.
• Particular operation appears to be a "bottleneck" holding up subsequent operations
• Standard times are required before an incentive scheme is introduced.
• A piece of equipment appears to be idle for an excessive time or its output is low, and it therefore becomes necessary to investigate the method of its use.
• The job needs studying as a preliminary to making a method study, or to compare the efficiency of two proposed methods.
• The cost of a particular job appears to be excessive

“Make sure first that the method is right”

Steps in making a time study

• Obtain and record all the information available about the job, the operative and surrounding conditions

• Record a complete description of the method, breaking down into "elements".

• Examine detail breakdown to ensure, the most effective method and motions are being used, and determine the sample size.

• Measure with a timing device (stop-watch) and record the time taken by the operative to perform each "element"

• Assess the effective speed of working of the operative relative to the observer's concept of the rate corresponding to standard rating.

• Extend the observed times to "basic times".

• Determine the allowances to be made over and above the basic time

• Determining the "standard time" for the operation

Obtaining and recording information

• Information to enable the study to be found and identified quickly when needed
• Information to enable the product being processed to be accurately identified
• Information to enable the process, method or machine to be accurately identified
• Information to enable the operative to be identified
• Duration of the study
• Working conditions

Breaking the job into elements

 An element is a distinct part of a specified job selected for convenience of observation, measurement and analysis

• To ensure that productive work is separated from unproductive activity

• To permit the rate of working to be assessed more accurately

• To enable the different types of element to be identified and distinguished

• To isolate elements involving high fatigue & allocate fatigue allowances accurately

• To enable a detailed work specification to be produced

• To enable time values for frequently recurring elements

- Repetitive element (picking up)
- Occasional element (machine setting)- Constant element (switch on machine)
- Variable element (push parts-Distance)
- Manual element (performed by worker)
- Machine element (automatically)- Governing element (longer time)
- Foreign element (part before study)

Deciding on the elements

• Should be easily identifiable, with definite beginnings and endings
• Should be as short as can be conveniently timed by a trained observer
• Elements — particularly manual ones — should be chosen
• Manual elements should be separated from machine elements
• Constant elements should be separated from variable elements.
• Small batch jobs which occur infrequently (require less detailed descriptions)
• Movement from place to place (require less description than hand & arm movements)

Sample size

Where,
n = sample size we wish to determine,
n' = number of readings taken in the preliminary study,
£ = sum of values,
x  = value of the readings.

 Timing each element: Stop-watch procedure

 There are two principal methods of timing with the stop-watch:

• Cumulative timing (watch runs continuously throughout the study Started at the beginning of the first element & not stopped until the whole study is completed)
• Flyback timing (stopwatch are returned to zero at the end of each element and are allowed to start immediately, the time for each element being obtained directly)