Cost Accounting (14th Edition)

QUALITY AS A COMPETITIVE TOOL 677
Number of Times Defect Observed
700
600
500
400
300
200
100
Copies are
fuzzy and
unclear
Copies are
too light
or too
dark
Paper
gets
jammed
Copies
are not
square
on
page
Toner is
smudged
on page
Paper
is not
feeding
properly
Exhibit 19-4
Pareto Diagram for
Photocopying
Machines at Photon
Corporation
Type of Defect
cause-and-effect diagram describing potential reasons for fuzzy and unclear copies. The
“backbone” of the diagram represents the problem being examined. The large “bones”
coming off the backbone represent the main categories of potential causes of failure. The
exhibit identifies four of these: human factors, methods and design factors, machinerelated
factors, and materials and components factors. Photon’s engineers identify the
materials and components factor as an important reason for the fuzzy and unclear
copies. Additional arrows or bones are added to provide more-detailed reasons for each
higher-level cause. For example, the engineers determine that two potential causes of
material and component problems are variation in purchased components and incorrect
component specification. They quickly settle on variation in purchased components as
the likely cause and focus on the use of multiple suppliers and mishandling of purchased
parts as the root causes of variation in purchased components. Further analysis leads
them to conclude that mishandling of the steel frame that holds in place various components
of the copier such as drums, mirrors, and lenses results in the misalignment of these
components, causing fuzzy and unclear copies.
The analysis of quality problems is aided by automated equipment and computers
that record the number and types of defects and the operating conditions that existed
at the time the defects occurred. Using these inputs, computer programs simultaneously
and iteratively prepare control charts, Pareto diagrams, and cause-and-effect diagrams
with the goal of continuously reducing the mean defect rate, μ, and the standard
deviation, .
Poor training
New operator
Inadequate
supervision
Human Factors
Flawed
part design
Incorrect
manufacturing
sequence
Methods and
Design Factors
Exhibit 19-5
Cause-and-Effect
Diagram for Fuzzy and
Unclear Photocopies at
Photon Corporation
Poor maintenance
Multiple suppliers
Poorly
machined parts
Incorrect speed
Inadequate
measurement
tools
Machine-Related
Factors
Variation
in purchased
components
Mishandling
of purchased
parts
Incorrect
component
specification
Materials and
Components Factors