By: Gilberto Jimenez, SQA Field Engineering Director

How many times have we heard this solution to a firefighting situation: “Let’s add an inspection point to ensure the customer does not receive bad product.” As logical as this may sound, it is not a valid solution. Adding inspection is costly and can only lower the risk of shipping bad product. It does not mean bad product will not be shipped.

Setting an inspection point involves two major decisions. The first is selecting the inspection plan to be used. When falling into a critical or firefighting situation, companies often do not select the ideal inspection plan because they do not have the historical data to support the selection. Therefore, in most cases, 100% inspection is selected. However, this unnecessarily increases the cost and resource requirements, and this in turn generates larger risk due to the lack of training necessary to achieve adequate inspection — the inspectors are not necessarily masters of the process.

The second decision involves selecting the inspection method. Since the inspection is typically not clearly defined nor formally analyzed through a detailed pFMEA, dFMEA, or any other risk or failure analysis method, there is no true understanding of whether the inspection point is correct or ideal. This potentially makes an inspection both an ineffective and costly exercise.

It is for these very reasons that SQA has established the concept of inspectioneering. This term indicates studied and planned inspections. Root cause analysis and planning are addressed before inspection activities are initiated.

Inspectioneering is based on failure mode data, which is basically failure data sorted by type of failure. Root cause analysis is performed on each failure incident to characterize the incidents by failure mode. While this may be difficult and even appear costly up front, it is a key part of any serious effort to understand, model, project and improve components, improve system reliability, and create an effective inspection plan. With this analysis, a true AQL or sampling plan — one that depends on the criticality of the characteristic to be inspected — may be selected.

Inspectioneering then focuses on closing the Deming circle. Once the inspection system is planned and checked, the action is monitored on a daily basis through meetings or GENBA, for day-to-day outcomes on the inspection line. This enables direct feedback to the quality engineers that can be used for training follow-up with the inspectors.