Prior to final design, a complexity analysis of the
selected design concept should be performed. The purpose is to identify those
attributes of the design that may be overly complex or that may require overly
complex manufacturing and assembly procedures. The intent is to attempt, if
possible, to eliminate all such features. If they cannot be eliminated, then the
analysis can form the basis for identifying additional efforts that may be
necessary to ameliorate manufacturing and assembly difficulties. This analysis
is most beneficial when performed by an independent team.
An example of reducing part count with the objective of
reducing complexity is shown in Figure
3.4. In this redesign of a conference
badge clip, a ten part assembly with fifteen assembly operations has been
reduced to a single part. Reducing part count may result in beneficial
reductions in assembly time and assembly errors and may prevent a possible
assembly work stoppage due to missing parts. However, the manufacture of single
part badge holder might introduce other complexities such as the need for a new
and/or poorly defined process or a difficult operational sequence and may, in
the end, result in a more expensive product whose cost cannot be justified. An
independent assessment of complexity is often necessary to determine the best
course of action.
Case Studies 34, 35,
presented in Appendix D
provide additional insight into the reduction of complexity on a variety of
different products in a number of industries.
Complex design attributes or features may require the
acquisition of new machinery, processes, or personnel capabilities. Complex
designs may cause schedule problems and cost overruns, as they present
significant risk areas and may cause impact on production by requiring an
unplanned, last minute, modification to the product or process. The complexity
analysis can result in simplifications to the design and recommendations to
reduce manufacturing and assembly difficulties.
Staff: The formal
complexity analysis should be conducted by a team of independent experts in all
disciplines associated with the product and should include at least one
producibility engineer who is expert at complexity analysis.
Once the preliminary manufacturing plan (3.4 ) has been
developed, a complexity analysis of the product and the processes should be
performed to attempt to prevent manufacturing cost and schedule problems. The
analysis should be conducted by an independent team of experts who are familiar
with complexity analysis.Steps in conducting a complexity analysis
1. Assemble the independent review team.
2. Determine complexity metrics to be assessed (design attributes or features, part count, process required, schedule, cost, tooling, etc.).
3. Analyze design against complexity metrics.
4. Recommend modifications to the design, as appropriate, and, as needed, to the manufacturing plan to incorporate the recommendations.
5. Document all assessments, analyses, and recommendations.
The recommendations of the complexity analysis team
should be presented to the IPT in a formal transmittal both orally and in
writing. It should be noted that the IPT does not have to follow all the
recommendations of the review team. In the end, the IPT is responsible for the