The Design for Six Sigma Process
In contrast to DMAIC, there is not a single methodology that has been widely adopted for conducting DFSS projects. Many companies, consultants and trainers have developed their own versions, but they largely include the same elements.
The most common framework is DMADV, which sounds similar to DMAIC because the first three phases have the same names, but differs in terms of the goals and tasks associated with those phases.
During the Define phase, the project team produces a detailed project charter, which clarifies the business need for the new process or product and establishes the project parameters. The business need portion of the charter incorporates a description of the problem or gap in offerings that the project will address, and a statement of the opportunity that exists for improved revenue, customer satisfaction, or market share should the gap be successfully bridged. An effective charter also spells out the project schedule, deliverables, and budget, and clarifies roles and responsibilities for team members and other stakeholders.
Once the charter is complete, the project team should also assess the culture of the organization in relation to the type and amount of change that is likely to result from creating a new process or product. An assessment of readiness for change at the organizational level and the individual stakeholder level provides valuable information about resistance the team may encounter. A communication plan and risk management plan are also critical elements in the Define phase.
The DFSS Measure phase focuses on understanding customer needs and translating them into design requirements. The project team may already have some data available to give them insights on what potential customers expect, but usually has to gather more using surveys, interviews, focus groups, or other techniques. Participants are asked for their input on the features and functions a product should have, the level of performance they expect from a service or product, and the criteria they would use to judge its quality and effectiveness.
One challenge in this phase is that potential customers of a new product or service may state certain needs, but may not state others that they either are not consciously aware of, take for granted, or do not think of during the feedback session. Team members can improve the quality of the information they gather by letting participants know that all input is valuable, and by using specific techniques such as contextual inquiry that can help uncover latent needs.
Once the project team has gathered sufficient customer input, members need to translate statements of customer need into specific metrics known as critical to quality (CTQ) metrics. A CTQ clarifies not only what it is that customers want, but how that characteristic can be measured and what target must be reached to satisfy them.
In the Measure phase of the Design for Six Sigma process, the project team determined the qualities of the new product, process or service that are critical to customer satisfaction. In the Analyze phase, the team uses that information to describe the functions that the new entity must incorporate, and brainstorms different high-level design options. They then use various assessment tools to determine how well each option meets customer and business needs. Teams generally use a combination of brainstorming techniques and benchmarking to come up with high-level design concepts and estimate their potential performance and success. Finally, the team uses a decision-making tool such as a Pugh matrix to evaluate the options and select a final design.
Once the DFSS project team has selected a high-level design, it is time to do detailed planning. Components of the design may include a physical product, a manufacturing process or service delivery process, supporting technology, and human resource support. Also important are decisions about materials and supplies, facilities, and equipment. For example, when creating a new software program, the team would address not only the details the program itself, but also related concepts such as how it will be sold, how support will be provided, where it will be manufactured, what technology is needed, and what type of packaging will be used.
With a preliminary designed worked out, the team needs to begin testing to ensure the design will meet customer and business requirements. Techniques include failure modes and effects analysis (FMEA) and computer simulation. The FMEA process gives teams a chance to identify potential risks, determine which are highest priority, and either alter the design or develop a mitigation plan. Simulation allows teams to work more fully through the processes and details and understand the process inputs and results. This phase ends when the team has a solid design plan for a new process, product or service that will meet customer requirements and business needs.
In the Verify phase, the team rolls out the new design and verifies that it does indeed perform as expected. Typically they start by conducting a pilot, which is a small-scale implementation. It may be a limited production run of a product, a limited service offering, or a short-term test of a new process. The project team uses the results of the pilot test to modify the design and process before initiating a full rollout. In both phases, they should create a detailed process map, develop detailed process documentation and instructions, and establish formal roles and responsibilities. At the end of the project, as in a DMAIC project, the team ensures that the process is ready to turn over to business leaders. As part of this, they should provide process documentation and a process monitoring plan. Finally, the team leaders complete project documentation, communicate the project outcomes and celebrate project completion.