Calidad

Metrics That Trigger Actionable Discussions: Prioritize Process Improvements Using Gauge R&R and SPC Capability
by Govindarajan (Govind) Ramu
If a typical process engineering review meeting at your organization involves engineers staring at scores of presentation slides and feeling overwhelmed, you may want to consider the metrics you’re using. High-level metrics like throughput yield and scrapmay seem like logical choices for regular product reviews, and they are useful at a business level; however, they tend not to trigger actionable improvement discussion. In contrast, the same powerful tools that engineers use in their everyday product development and process management applications can have enhanced benefits when put to work for broader decision making about improvements.Integrating tools like failure mode and effects analysis (FMEA), gauge repeatability and reproducibility (GR&R), and statistical process control (SPC) provides a quality improvement framework that organizations can use to monitor process health, prioritize improvements, and assign resources to actions that warrant most attention. Figure 1 shows how FMEA, GR&R, and SPC can be analyzed in the context ofrelationships between critical to quality (CTQ) and critical to process (CTP) parameters, leading to creation of a “process health card.” In eight steps, you can build your own process health card and begin using it at your engineering review meetings. With your focus strongly on metrics of practical interest to product and process engineers—GR&R results, SPC stability status, and the potential riskto the organization of rejecting good parts or accepting bad parts (misclassification) which impacts the organization’s cost of poor quality—you should find it easier to engage in the actionable discussions that the meeting should foster. Step 1: Identify CTQs and CTPs It is not unusual for the different product lines in any business unit’s portfolio to have many quality characteristics in commonand others that are entirely unique. Defining and documenting quality characteristics for each product line is a crucial activity that should be the responsibility of crossfunctional teams. First, assemble a team consisting of product line management; account management; and research and development, quality and manufacturing engineering, and customer representation. Where customer representationis not practical, the quality department, marketing, sales, or account management should provide support on behalf of the customer. This team is assigned with critical to quality (CTQ) characteristics identification. For the same product line, assemble a second team for the purposes of critical to process parameter (CTP) identification related to the CTQs. Include manufacturing, quality,equipment, and production engineers, and invite R&D engineers where applicable. It is beneficial to maintain the team members of R&D, quality, and manufacturing engineering from the CTQ team in the CTP identification exercise. The team assigned with the task of identifying the critical to quality characteristics should use resources like voice of the customer tables, customer surveys, scorecards, marketneeds, engineering specifications, and contracts to identify basic and perceived requirements and delighters for the product. The team should further brainstorm any new expectations for the product. (This exercise will yield critical to quality characteristics that are both qualitative and quantitative, but this article focuses on the quantitative.)
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Figure 1. An Integrated Model for Quality Improvement
This eight-step model begins with CTQ and CTP identification and leads to the creation of a process health card. Integrating tools like FMEA, GR&R, and SPC provides a quality improvement framework for monitoring process health, prioritizing improvements, and assigning...