Page 63 - Design for Six Sigma for Service (Six SIGMA Operational Methods)

44 Chapter Two

Step 1: Measure the Current Process Performance Levels Based on
Process Performance Metrics

For example, in the restaurant service case, if the performance metrics for
the kitchen workflow process are
• Time from ordering to meal delivery
• Taste of food
Then the time from ordering to meal delivery can be measured by a
stopwatch; a sample (such as 50) of such time measurements can be taken
and recorded. The mean, standard deviation, and range can be used as the
basic statistical estimates for performance evaluation. The histogram of this
data set can be used as the basis for simulation model parameters. The taste
of food can be measured by a scaled taste evaluation.

Step 2: Determine Performance Requirements That Meet
These Customer Needs
In this step, the required target values for all process performance metrics
should be established. These target values could be based on competitive
benchmarking. The DFSS tool used in this phase is basic statistical analysis.

2.4.3 Phase 3: Analyze

The objective of this phase is to analyze the existing design and generate
alternative process design options to meet the performance needs. This
phase has the following steps.

Step 1: Perform a Process Diagnosis for the Current Process
The goal of process diagnosis is to identify the key weaknesses of the
process and provide the guidelines for process redesign and improvements.
The following approaches are often used in process diagnosis:
1. Value stream map analysis: A value stream map can expose non-
value-added activities and process efficiency problems. By using lean
operating principles to analyze the current state value map, possible
improvement ideas can be generated.
2. Process map analysis: A real detailed process map may expose
“hidden factories,” that is, unnecessary loops and steps. This process
map analysis may help to generate process improvement ideas.
3. Process analysis based on process types: The knowledge outlined in
Sec. 10.3 can also be used to analyze the possible weaknesses of the
process. For example, if we find that our process is an office process
but we use a job shop type of layout, then we can immediately know