A traditional Quality Assurance Inspection Plan can be very expensive and is not typically as effective as an organization might think.
Quality Assurance (QA) Engineering may create quality assurance testing of a product based on acceptance quality level (AQL) testing or some other product testing variation. In addition, an organization’s Quality Assurance Surveillance Plan (QASP) or some other agreed-to product performance document may be based on this quality assurance plan.
However, as W. Edwards Deming in his book, Out of the Crisis book states, “Inspection does not improve the quality, nor guarantee quality.
AQL testing is an example of Deming’s “inspection does not improve quality” point. In addition, AQL testing has some fundamental technical issues that those in QA Engineering and others involved with this quality assurance test approach do not typically appreciate.
A Traditional Quality Assurance Inspection Plan and Associated Costs
A traditional quality assurance inspection plan may look like:
The cost of implementing such a plan can be huge. For example, an organization can utilize two or more inspectors to execute this plan for only a couple of products, resulting in $50,000 – $100,000 annually expense. In addition, with the above traditional inspection plan, there is no focus on improving the product manufacturing process, so future products have improved quality; i.e., the annual inspection cost can have little value-add for the organization as a whole.
What an organization should strive to achieve in time is improved product quality so that no inspection is required; however, to accomplish this desire, something needs to be done differently.
An Integrated Enterprise Excellence (IEE) Quality Assurance Testing and Process Improvement Plan
A traditional quality assurance inspection plan focuses on assessing a lot to determine if it is ″good enough.” Often with AQL testing, if a lot failed its test, but if the same lot were tested again, it could pass because of the statistical probability of AQL test-lot sampling. This statistical probability reality is a fundamental problem with AQL and other similar forms of lot-sampling testing.
Traditional quality assurance inspections do not focus on the fact that individual lots are the result of the process that created the product. Because of this, it is more critical to conduct inspection plans (and their reporting) from a process output point of view, as opposed to individual product-lot testing.
Traditional Process Capability Statement Reporting Problems
Another point that needs emphasis is that an organization or its customers may establish process capability indices requirements that have fundamental problems, as described in the article “Process Capability Problems And Solutions: Resolving Process Capability Index Issues For Cp, Cpk, Pp, Ppk.” In addition, Cp, Cpk, Pp, and Ppk metrics are difficult to understand throughout an organizational chart.
This article also describes the benefits of a 30,000-foot-level metric reporting alternative, which has many advantages over traditional process capability Cp, Cpk, Pp, and Ppk reporting.
Measurements Reporting from a High-level Viewpoint with Easy-to-understand Process Capability Statement Wording (In One Chart)
When inspection plans are created from a 30,000-foot-level process-output point of view, a predictive statement is provided at the bottom of the chart if the process (from a high-level viewpoint) is considered stable. When a predictive statement is deemed unsatisfactory, this futuristic expectation would “pull” to execute enhancements to the metric’s associated process.
In 30,000-foot-level reporting, the capability of a process report out is much easier to understand units than with process capability indices of Cp, Cpk, Pp, and Ppk. A 30,000-foot-level report-out would provide an estimate for the expected non-conformance rate when a specification exists at the bottom of the chart. For example,
A Quality Assurance Inspection Plan that Reduces Costs while Improving Long Lasting Product Quality
The following could be edited and used to replace the traditional shown organizational inspection plan for the product requirement shown above.
- Create a 30,000-foot-level chart for each critical product/process measurement. An app is available for creating 30,000-foot-level charts for a variety of process-output-response types. There are educational videos and reference instructions available on this link that can be used to develop 30,000-foot-level charts for a variety of dataset types. Also, free one-on-one assistance is available by scheduling a ½ hour Zoom meeting or contacting Smarter Solutions, Inc. via e-mail or phone.
- Examine the response of each tracked quality-assurance-inspection-plan response to determine if action is required or not.
- No action is required if the 30,000-foot-level statement is stable and the prediction statement is satisfactory.
- Action Type 1: Resolution to a special cause signal(s) can be appropriate when a measurement(s) is beyond an individuals 30,000-foot-level chart control limit(s).
- Action Type 2: Process improvement action can be appropriate if a 30,000-foot-level predictive common-cause statement (bottom of the chart statement) is not considered satisfactory relative to the achievement of internal or external customer requirements.
Automatic Reporting of Product Metrics
Automatic reporting of quality-assurance-inspection-plan metrics can be accomplished through the Integrated Enterprise Excellence (IEE) system and its Enterprise Performance Reporting System (EPRS) software, which could be installed behind an organization’s firewall.