Page 101 - Six Sigma for electronics design and manufacturing

Six Sigma for Electronics Design and Manufacturing
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1. Manufacturing variability measurement and control (Section 3.1).
Statistical process control (SPC) is the key to maintaining and im-
proving the manufacturing process variability. The tools for SPC
are presented, with emphasis on control charts and their proper
use in the manufacturing environment. These tools can be used
collectively for improving quality by collecting and analyzing de-
fects data to determine the most probable causes of defects and
counteracting them.
2. Control of variable processes and its relationship to six sigma (Sec-
tion 3.2). The control of variable processes involves taking periodic
or daily actual measurements of the quality characteristic and
comparing the measurement to historical values. This section is fo-
cused on X and R charts. the statistical basis of these charts are ex-
amined, as well as their mathematical relationship to six sigma
concepts, including various methods of relating the two concepts,
with detailed discussions and examples. In addition, the issues of
managing the variable control charts and recalculating the chart
data are also presented.
3. Control of attribute processes and its relationship to six sigma. In
Section 3.3, various types of attribute charts are presented, togeth-
er with their underlying distributions and relationship to six sigma
concepts. Calculations of chart data and their mathematical rela-
tionship with six sigma are also presented with formulas and ex-
amples. The C chart is shown to be well suited for six sigma appli-
cations.
4. Using TQM techniques to maintain six sigma quality in manufac-
turing (Section 3.4). In factories approaching six sigma quality, the
need for sampling techniques such as control charts to maintain
and monitor quality are diminished. Individual defects can be ana-
lyzed and corrective action taken accordingly on a daily basis.
TQM tools can be used in these factories to maintain and even im-
prove quality beyond six sigma. This section presents the TQM
tools, their major functions, and how they can be used in the cor-
rective action process.
3.1 Manufacturing Variability Measurement
and Control
Control charts have been traditionally used as the method of deter-
mining the performance of manufacturing processes over time by the
statistical characterization of a measured parameter that is depend-
ent on the process. They have been used effectively to determine if the
manufacturing process is in statistical control. Control exists when