Process charts used in method study


1. Outline process chart:

An outline process chart records an overall picture of the process and records only the main events sequence-wise. It considers only the main operations and inspections.

2. Operation process chart:

The basic process chart, called an operation process chart, is understood as a graphic representation of the points at which the materials are introduced into the process and of the sequence of inspections and all operations except those involved in materials handling. It includes information considered desirable for analysis such as time required to carry out the operation and the location.

3. Flow process chart:

Flow process charts are graphic representations of the sequences of all operations, transportation, inspections, delays, delays and storages occurring during a process or a procedure and include information considered for analysis such as, time required and distance moved.

The flow process chart could be of three types namely,

(i) Flow process chart material or product type.

(ii) Flow process chart – man type.

(iii) Flow process chart machine type or equipment.

Material or product type flow process chart records what happens to the material or product i.e. the changes the material or product undergoes in location or condition (includes operation and transportation). Man type process chart records the activities of worker or operator i.e. what a worker or operator does, whereas equipment or machine type flow process chart records the manner in which an equipment or machine is used.

Two handed process chart:

In this chart, the activities of a worker’s or workers’ or operator’s both hands or limbs are recorded chronographically.

Multiple Activity Chart:

In this chart, the activities of more than one subject worker, machine or equipment are recorded on a common time scale to show their inter-relationship.

The man machine chart or worker-machine chart:

This is a variation of multiple activity charts and illustrates the operation and delays of the operator and the machine which he operates. An example of man machine chart may be one worker running two machines simultaneously.

Flow diagram:

The flow diagram is a drawing or diagram drawn to a scale to show the relative position of a machine or equipment, jigs and fixtures, gangways or aisles and shows the path followed by materials or machines.

String diagram:

It is scale plan or model on which a string or a thread is used to trace and measure the path of workers, material or equipments during a specified sequence of events.

SIMO chart:

Therbligs indicate the basic motions consisting of three parts, viz.,

(i) When the motion begins.

(ii) The nature of the motion.

(iii) When the motion ends.

The simultaneous motion cycle chart (SIMO) is a type of two handed process chart in which the micro motions (therbligs) of both hands are recorded.

Motion Study:

Motion study is the science of eliminating wastefulness, resulting from using unnecessary; ill-directed and inefficient motion. The aim of motion study is to find and perpetuate the scheme of the least waste methods of labor.

Micro motion study provides a valuable technique for making minute analysis of those operations that are short in cycle, contain rapid movements and involve high production over a long period of time. For example, sewing of garments and assembling small parts. Micro motion study may be used for the following purposes in addition to its primary use for job-analysis work:

(i) To study the inter-relationship among the members of a work group.

(ii) To study the relationship between an operator and the machine which he operates.

(iii) To obtain the time for an operation.

(iv) To establish a permanent record of the method of doing a job.

The usual procedure of performing a micro-motion study is to take motion picture of the operations, analysis the film and to prepare a SIMO chart from the results of the film analysis. In analyzing the film, very small time values (commonly 1/2000 minute) may be obtained by reading a clock (micro-chronometer) that appears in each of the motion pictures.

The film is analyzed by breaking the job cycle into micro motions or therbligs which indicate the basic body motions of the workers.