Page 401 - Design for Six Sigma a Roadmap for Product Development

370 Chapter Ten

recommended for specific items in the customer manual, if any. In
this category, customers expect less frequency and more ease. Under
the pressure of minimum life-cycle cost, many companies are pushing the
scheduled maintenance tasks to standard operations and “Do it yourself”
procedures. A sound scheduled maintenance procedure should call for
better reliability and durability, minimum tools (e.g., single standard
fastener size), and easy removal paths. In repair service, ease of repair
is key. This objective is usually challenged by limited accessibility
space and design complexity. Repair service can be greatly enhanced
by employing some sort of diagnostic system, repair kits, and modular
design practices. Repair issues can take a spectrum of possible causes
ranging from type 1 to type 2 errors in diagnostics systems, tools and
parts logistics issues, and repair technicality.
3. Practice the DFS approach. If the serviceability requirements have
not been serviced by now, the DFSS team is encouraged to use design
mappings by employing the zigzagging method between serviceability
FRs and its DPs. Once the team has identified all serviceability map-
ping, they can move to consider design alternatives. These alternatives
may occasionally be inapplicable. In other cases, they may seem in con-
flict with one another. Nevertheless, the DFSS team should review the
entire process to determine whether a Six Sigma–capable and rounded
design is to be established in all requirements, including those related
to serviceability. A serviceability set of FRs usually includes proper loca-
tion, tools and parts standardization, protection from accelerated fail-
ure, ergonomics considerations, and diagnostic functions.
The DFSS team should generally perform the following steps to
devise a sound DFS approach:

1. Review assumptions, serviceability customer CTSs and FRs from the
QFD, serviceability types, customer segments, and Six Sigma targets.
2. Check datum designs and use the data available as a way to predict
their design performance from datum (data) historical database(s).
The team should also benchmark best-in-class competition to
exceed customer satisfaction.
3. Identify types of service needed (e.g., standard operation, scheduled
maintenance, or repair) and map them to appropriate customer seg-
ments.
4. Understand all service procedures in the company core books,
including steps, sequence, and potential problems.
5. Estimate time of labor. Labor time is considered the foundation of
serviceability quantification for warranty assessment purposes. It
is the sum of repair recognition time, diagnostic time, logistic time,
and actual repair time. The team should aim to beat the best-in-
class labor time.