TOPS (Team Oriented Problem Solving): A core requirement for problem solving and process improvement efforts. It is adopted for usage in the d2σ process without significant changes, but operator involvement is a must.
Cost Systems: Cost of Quality (prevention, appraisal, internal failures, and external failures) with additional input from standard cost accounting systems, emphasizing Juran’s Language of Money. Also adopted without significant changes.
MSA (Measurement System Analysis): The standard calculations are applicable to the d2σ process, but the implementation is more stringent than normal. If d2σ conditions are achieved, traditional measurement systems frequently become the primary limiting factor of process optimization efforts.
SPC (Statistical Process Control): SPC remains critical for process monitoring, but d2σ process control charts may not demonstrate a state of statistical control. This results when a gaging system cannot discern variation in d2σ manufactured product.
Process Paths: Determination of process paths, or streams, and knowledge of the inherent variation that they can introduce into a process is required. More than process mapping or simple flow charting, the path concept examines the process in detail.
DoE (Design of Experiments) and SNR (Signal to Noise Ratio Analysis): Taguchi Methods and Signal-to-Noise Ratio Analysis are used in the pursuit of d2σ processes. The inclusion of “noise” in process analysis steps enhances the ability to establish stable manufacturing processes and the application of SNR techniques is critical to identify the causal factors of process dispersion.
MRATs (Multiple Response Analysis Tables): The practical use of this technique enables the selection of process inputs at levels that will improve targeting, minimize dispersion, and minimize overall manufacturing costs for the greatest number of output characteristics concurrently.
It should not be a surprise to discover that d2σ and Six Sigma do have some common elements. The original Six Sigma goal was, after all, achieving ±6σ processes. Small wonder then, that d2σ also starts with some of the same elements that have been a part of process control and quality improvement efforts for decades.