Page 51 - Six Sigma for electronics design and manufacturing

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The Nature of Six Sigma and Its Connectivity to Other Quality Tools
1.11.1 Process mapping
Process mapping is a structured approach focused on improving
processes to deliver the highest quality and value of products and
services to the customer. It is based on structured analysis (SA) and
structured designs, which were tools that were developed for the soft-
ware industry as a means toward hierarchical decomposition and de-
scription of software modules. Structured analysis and design were
developed to replace the traditional tools of flowcharting as software
projects and programming complexities increased.
The advantage of process mapping is the presentation of informa-
tion flows between different systems and departments in a graphical
manner. Using a hierarchical approach, process mapping allows for
easy understanding of a complex system or process. Process mapping
has been used successfully in management information systems to de-
sign the information and data flows for manufacturing operations. It
could also be used to describe the complex marketing, sales, manufac-
turing, and quality systems that are used to develop and introduce
new products to manufacturing and the marketplace.
Structured analysis uses few symbols and techniques to present a
complex system or operation. The top-level boundary of the system be-
ing described is called the context diagram, and the decomposition of
the system into smaller, more detailed units is called data flow dia-
graming. This process, known as “top-down partitioning,” occurs
when data flow diagrams are decomposed from a very high level and
general view of the system, to a very detailed view of specific opera-
tions.
A data flow diagram may be defined as a network of related func-
tions showing all data interfaces between its elements. These ele-
ments are:
The data source or destination, represented by a rectangular box. A
source is defined as an originator of data and a destination is de-
fined as the target for data receipt. Sources and destinations are
used to determine the domain of the study of the system, such as
departments, suppliers, and customers.
The data store is represented by two parallel lines or an open box.
It represents a repository of information. Data can be stored in
electronic files or in physical locations such as file drawers. The
name of the file or the storage system should be written alongside
the symbols. In complex diagrams, the same data stores might be
drawn at different locations to minimize nesting of the lines. In
these cases, another vertical line is added to the symbol to indicate
that it is repeated elsewhere in the diagram.