Page 81 - DMGT206_PRODUCTION_AND_OPERATIONS_MANAGEMENT

Production and Operations Management

Notes 4.3 Analytical Tools

Quality has became a very serious issue in mass production systems because no longer are the
parts hand-built and individually fitted to the product. Mass-produced parts have to function
properly in every product built. Management wants as little total variation in a process as
possible—both common cause and special cause variation.

Reduced Variation

1. Reduced variation makes the process more predictable with process output closer to the
desired or nominal value.
2. The desire for absolutely minimal variation mandates working toward the goal of reduced
process variation.

Product or Service Inspections

1. Product or service inspections generate data on variations of characteristics, processes and
products.
2. Several ways are used to generate data by the measurement of specific characteristics of
the product or process.

Once the specific data has been collected, valuable techniques, such as check lists, bar charts, scatter
diagrams, Pareto analysis, fish-bone diagrams, etc., can be used to analyze and find ways to reduce
process variation, communicate quality issues, etc. Each of the tools may be used independently,
but their power grows if they are combined or used together. In solving a quality problem,
managers often shift data to clarify the issues involved and deducing the causes.

The analytical tools discussed below are used in traditional quality improvement programs.
They are also used in Six Sigma, though their application and integration in a corporate wide
management system is in some ways unique.

4.3.1 Checklists and Tally Charts

Two common methods to capture the data are (a) checklists, and (b) tally charts.

Checklist

A checklist is a form used to record the frequency of occurrence of certain product or service
characteristic related to quality, and is often the first step in the analysis of quality problems.

Figure 4.5: Checklist

Tally Chart

A tally chart is, similarly, a quick way of counting how many occurrences there are in each
category. These are counted in order and a mark put in the correct place. When you get to 5, put
a mark across, i.e., the fifth mark is the crossing line.

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