In order to support the continued development of the
enterprise in its quest to improve producibility, the development of design
guidelines is strongly recommended. Such guidelines contain the rules and
procedures for improving producibility. They are based on expert knowledge and
lessons learned from previous product development efforts. They form a unique
knowledge base for the enterprise.
These guidelines may range from very simple
recommendations to quantified requirements including specific methods and
metrics. By setting metrics and measuring performance against those metrics,
quantitative data that can highlight areas for design improvement and indicate
areas of technical risk are developed. This quantitative information can support
the development of additional guidelines as well as revisions to current
The guidelines are a tool for both the experienced
engineer and designer as well as the novice. They provide the parameters within
which the design engineer should operate. However, it should not be a rigid rule
book. The intent is to provide guidance and to avoid repeating known mistakes,
not to hinder innovation and restrict resourceful improvements.
Design guidelines are applicable at every phase of the
product development, from concept to detailed design. They are particularly
important during concept development as they set the stage for the top-level
requirements that flow down from conceptual and detailed design to the
manufacturing processes for the final product.
Guidelines can also be used to incorporate changes in
design parameters and tolerances to facilitate ease of production during a
particular manufacturing process. Specific guidelines such as these must be
individually developed and be based on specific capabilities. This assumes
that the techniques of product simplification, standardization, and component
selection have been incorporated (see 3.5 and 4.2
). This is a systematic
customizing effort aimed at maximizing production efficiency through product
design. To support this activity, some organizations develop tailored,
product-specific, design guidelines that are based on their general
Case Studies 11 and 12 in Appendix D provide additional
insight into the importance and use of design guidelines.
The establishment and maintenance of design guidelines
provide the organization with the ability to avoid past mistakes and take
advantage of the best knowledge available for addressing producibility. Design
guidelines can be viewed as a risk mitigation action that assists in the
considerations of producibility in every aspect of development and design.
(See the discussion on implementing a risk management program in 1.3
design guidelines requires personnel capable of collecting lessons learned and
translating the information to a specific set of design guidelines as applied to
a functional specialty. This should be done by a corporate team, not a product
specific team, that should be composed of experts in design, manufacturing, and
customer support. This design guidelines team should function similarly to an
IPT but should be focused on the entire enterprise and not on an individual
Tools and Techniques: A Database Management System can serve as a good
repository of the lessons learned. An overview of database management systems
is presented in Appendix F.1.3.
Decision Support Tools are useful for extracting information from database
systems, analyzing the data, and displaying the results in useful formats (Appendix F.1.4). Knowledge-Based
Systems can provide a means for gathering, cataloging, and retrieving the
knowledge of experts (Appendix
F.1.10). In addition, the application of Root Cause Analysis (Appendix F.1.19
may be useful for identifying the causes of manufacturing problems to support
the development of design guidelines.
functional specialists may require training in the process of converting a known
problem to its root cause and then developing specific guidelines. As necessary,
training may be needed in the use of Database Management Systems, Decision
Support Tools, Knowledge-Based Systems, and Root Cause Analysis.
Design guidelines can come in many forms, from published
checklists and standards to case-based reasoning incorporated in the designer's
workstation. Whatever their form, producibility guidelines must be readily
available and user friendly, and designers and engineers must know that they
exist and must apply them. Management must be committed to the development and
implementation of the guidelines and must provide the resources needed.
Management should establish a corporate design guidelines team with the
responsibility of collecting and maintaining the design information.
To develop and maintain these guidelines, time and
resources must be allocated for collection, classification, continuous
updates, and storage. Sources of information for developing guidelines
include: product requirements, material properties, risk analyses, lessons
learned from similar products, process variances, assembly process analysis,
process and design failure mode and effects analyses (FMEAs) (Appendix F.1.7), design
of experiments (DOE) (Appendix
F.1.6), published checklists, experience, employee surveys, and
consultants. Information gathered in 2.1
on current processing capability and from the measurement of processes and
products during production (see 5.1 and
) are essential elements of the guidelines. Instituting a
discipline of post-mortem analysis following disruptions to the manufacturing
process or test failures ensures that real-time lessons learned are collected