Page 215 - Six Sigma for electronics design and manufacturing

Six Sigma for Electronics Design and Manufacturing
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fect at the customer is estimated by a monetary value of the expected
level of customer dissatisfaction with that defect. The strategy is to al-
low for a shipping tolerance at the factory narrower than the adver-
tised specifications.
One of the obvious difficulties of the QLF strategy is the monetary
estimate of customer dissatisfaction. It is larger that the cost of re-
pairing or replacing a defect at the customer, since it includes the cost
of removing the defective unit as well the loss of the use of the product
and customer dissatisfaction.
A practical quality and cost approach is to use six sigma and its as-
sociated tools to calculate the potential number of defects in design
and manufacturing. The result will be added to a cost model as fol-
lows:
The quality level will be used to estimate the number of defects to
be found in the product based on its current configuration.
The defective parts will be replaced and the replacement cost added
to the manufacturing operation cost.
The defects generated will have to be removed through testing and
inspection, and an estimate of the removal cost will be added to the
model depending on the type of test performed.
The model can be used to monitor the cost trade-offs in the selec-
tion of alternate design methodologies, materials, and manufactur-
ing processes, as well as different test methodologies.
6.3 Electronic Products Cost Estimating Systems
Typically, PCBs account for 90% of the total material cost of an elec-
tronic product. Developing PCB cost models can vary depending on
the accuracy level needed. Consumer products are sensitive to cost
variation, whereas new technology products are less sensitive.
The electronic design cycle and its implementation in PCBs is divid-
ed into several steps. For most current electronic design activities,
computer aided engineering (CAE) is used to document the design
and provide the basis for electronic analysis and iterations of the de-
sign. Its function is also to physically partition the design into distinct
electronic groupings or models that are then incorporated into each
PCB. It also acts as a data source for further steps in the cycle. Figure
6.5 shows the steps involved in the PCB design cycle which are:

The logical design phase of matching the product specification re-
quirements by completing the electronic circuits design, selecting
the components, and documenting the circuit connectivity.