Work Measurement: Direct Time Study

Direct Time Study

• A method of observing and recording the time taken to accomplish a task using a stopwatch or other timekeeping device.
• Five steps in Direct Time Study:
  • Define and document the standard method
  • Divide the task into work elements
  • Time the work elements to obtain the observed time
  • Rate the worker's pace to determine the normalized time
  • Apply allowances to compute the standard time

Define and document the standard method

• Reasons for defining and documenting the standard method:
  • Provide work instructions for future batches
  • Distinguish if the worker has made method improvements
  • Use as a reference document to settle disputes and complaints
  • Provide data for a standard data system
• Information to be obtained:
  • Study number, sheet number, name of the analyst, date of the study, and name of the person approving the study
  • Information about the product or part being processed
  • Information about the process, method, plant, or machine used
  • Information about the workplace layout
  • Working conditions (temperature, humidity, lighting, etc.)

Divide the task into work elements

• An element is a distinct part of a specified job selected for convenience of observation, measurement, and analysis.
• Types of elements:
  • Repetitive element: occurs in every work cycle (e.g. picking up a part prior to assembly)
  • Occasional element: does not occur in every work cycle, but may occur at regular or irregular intervals (e.g. adjusting machine settings)
  • Constant element: basic time remains constant whenever performed (e.g. measuring diameter)
  • Variable element: basic time differs in relation to some characteristics of the product, equipment, or process (e.g. sawing wood with a handsaw)
  • Manual element: performed by a worker
  • Machine element: performed automatically by a machine or process
  • Governing element: occupies a longer time within a work cycle than any other element being performed concurrently
  • Foreign element: does not form part of the operation being studied (e.g. sanding the edge of a board before planning has been completed)

Time the work elements to obtain the observed time

• Two methods:
  • Snapback timing method: start and stop the watch at the beginning and end of each element
  • Continuous timing method: zero the watch at the beginning of the first cycle and allow it to run continuously throughout the study

Rate the worker's pace to determine the normalized time

• Performance rating: necessary when the worker is performing the task at a pace different from the organization's definition of standard or 100% performance.
• Performance rating converts the observed time into the normal time, which is the time that would be required at 100% performance.

Apply allowances to compute the standard time

• Add allowances for personal time, fatigue, and delays to the normal time to obtain the standard time.

Sample Problems

• Various examples of direct time study applications, including manual tasks and worker-machine tasks.### Work Measurement and PMTS
• Work Measurement is a technique used to establish the time required to perform a specific task or job.
• PMTS (Predetermined Motion Time Systems) is a work measurement technique that deals with microdata analysis of human motions.
• PMTS does not use a stopwatch to measure time, reducing inaccuracy.
• It works on the assumption that all manual work in an industry is comprised of basic individual motions, which are common in all jobs.

Objectives of PMTS

• Compare the time for alternative, proposed methods to examine the economics of proposals before production.
• Use time values to construct any time-scale, methods analysis charts, and methods improvement procedures.
• Compute an estimate of manpower, equipment, and space requirements prior to production.
• Develop tentative layouts for assembly lines prior to construction to minimize subsequent rearrangement and rebalancing.
• Determine job time standards.

Steps in Collecting PMTS Data

• Select a large number of workers doing various jobs under normal working conditions in industries.
• Record job operations on film (micro-motion study).
• Analyze the film, note the time taken to complete each element, and compile the data in a table or chart.
• Use the table or chart to estimate the time taken for basic motions in a new product.

Methods Time Measurement (MTM-1)

• It is a procedure that analyzes any manual operation or method into basic motions required to perform it.
• It assigns a predetermined time standard to each motion, determined by the nature of the motion and the conditions under which it is made.
• MTM-1 data are the result of frame-by-frame analyses of motion picture films of diversified areas of work.

Maynard Operations Sequence Technique (MOST)

• It is a simplified system of MTM developed by Zandin (1980) and originally applied at Saab-Scania in Sweden in 1967.
• Analysts can establish standards at least five times faster than with MTM-1, with little sacrifice in accuracy.
• MOST is used primarily in industrial settings to set the standard time for a worker to perform a task.
• MOST levels: Maxi MOST (higher level), Basic MOST (intermediate level), and Mini MOST (lower level).

The Learning Curve Theory

• The theory proposes that as the total quantity of units produced doubles, the time per unit declines at some constant percentage.
• Typical rates of learning are: 70-80% for large or fine assembly work, 80-90% for welding, and 90-95% for machining.
• The learning curve is a power curve of the form y = kxn when linear graph paper is used.
• Counterintuitively, 70% is the highest rate of learning, characteristic of a very manual operation, while 100% would be no learning, for fully automated operations.### The Learning Curve Theory
• The learning curve is represented by a curve on log-log paper.
• To find the slope of the curve, use the formula: n = Δy / Δx, where n is the slope, Δy is the change in y, and Δx is the change in x.
• In the example, n = -0.4152, which means the learning curve is 75%.

Wages and Wage Incentives

• To generate highly productive and satisfied workers, a company must reward and recognize employees for effective performance.
• Experience shows that workers do not give extra or sustained effort unless some incentive, either direct or indirect, is provided.
• Only about 25% of manufacturing employees are currently on incentives, and doubling this figure could lead to large increases in productivity.

Types of Wage Incentives

• Day work plans: compensate employees based on the number of hours worked times an established hourly base rate.
  • Build healthy employee attitudes and stimulate employee morale.
  • May not directly increase productivity.
• Flexible compensation plans:
  • Include individual incentive plans and group incentive plans.
  • Relate worker compensation to output.
  • Examples: piecework plans, standard hour plans.
• Piecework plans:
  • Standards are expressed in money, and operators are rewarded in direct proportion to output.
  • Day rate is not guaranteed.
• Standard hour plans:
  • Offer advantages of piecework and eliminate major legal problems.
  • Operate under a day work plan up to 100% productivity, and under piecework beyond 100% productivity.

Employees and Motivation

• Industrial engineers must understand psychological and sociological reactions of employees' attitudes toward methods, standards, and wage payment.
• Three key points to recognize:
  • Most people do not respond favorably to change.
  • Job security is a top concern for most workers.
  • People have a need for affiliation and are influenced by the group they belong to.

Maslow's Hierarchy of Human Needs

• Physiological needs: corresponding to survival, food, water, and health.
• Safety needs: security, physical and psychological.
• Social needs: attention, friendship, social belonging, and meaningful relationships with coworkers.
• Self-esteem needs: competence, achievement, self-respect, and ego satisfaction.
• Self-fulfillment needs: personal fulfillment, ego satisfaction, and varying individual needs.

Work Study and Measurement

• Question 1: Determine the normal time and standard time for a cycle using the snapback timing method.
• Question 2: Determine the normal time and standard time for a cycle using the continuous timing method in direct time study.
• Question 3: Create a MOST calculation for an activity (putting a thumbmark on a prepared document).

MOST (Maynard Operations Sequence Technique)

• A method for analyzing and improving manual and repetitive tasks.
• Example: calculating the time for an activity (putting a thumbmark on a prepared document).

Note: MOST is a method for analyzing and improving manual and repetitive tasks. It is not a part of the original text, but it is mentioned in the example question.