Root Cause: It may take some digging to find it

Quality programs, such as QS 9000 – common to the automotive industry, use the concept of root cause analysis in problem solving. The person new to the system is frequently tempted to quickly jump at the answer without depth of investigation.  A quality review that discovers quick assumptions being made by management will take this as weaknesses in company operations.

  Quality programs have been the way of life for operations in the aviation manufacturing business since WWII, but it has spilled over into other industries in modern times. Quality companies seeking certification under quality programs such as ISO 9000 will have to learn the discipline of digging for the root cause. For example, an airliner crashes, and on the surface it appears to be pilot error, frequently the first assumption made by the FAA. The crash investigation team knows better. There is much digging to be done.

  In the industrial setting, a quality certified operation demands the discipline of root cause analysis.  For example, a manufacturer of car seat actuators was challenged by an annual cost reduction challenge, which is common to automotive operations. The cost reduction challenge was passed down to the gear manufacturer, a subcontractor, and the gear manufacturer sought ways to reduce material cost. One common approach is to go offshore with material and/or manufacturing requirements. Since changing the source of material and manufacturing requires prequalifying the new source, samples of the offshore products need to be cycled through the engineering, manufacturing, and quality operations. Testing, similar to the original qualification testing, needs to be repeated. This is the normal course of events when developing alternate sources.

  If the new parts performance measure up to original parts performance, then the new source is qualified, and parts can now be sourced from off shore. The other possible outcome is that there are significant shortcomings in the new parts, and the offshore source needs to be sidelined until quality issues are cleared up. Proceeding without prequalifying testing could cause havoc in the field. The following is a possible scenario that reflects lack of quality discipline.

  The new source of gears is accepted without prequalification testing, and the new parts are built into the product. The seat actuators are shipped worldwide, and they are installed into sedans and vans representing the spectrum of vehicles all the way up to luxury cars. Then there is a rash of part failure across the board – in some cases with serious injuries resulting.  The sales outlet CEO is screaming; the parent organization officers are screaming; the domestic original product manufacturer is embarrassed, and they are eager to help.

  Root cause analysis is brought into play. The new products are collected and sidelined for belated qualification testing. The original source production line is reactivated to produce qualified products, and the pipeline is filled with originally qualified products. Meanwhile, the new assemblies made from unqualified parts are cycled through the qualification testing series. Notable differences are found in the performance of new actuators, and the new source is condemned. The chain of events can be summarized as follows: 

Seat failure > actuator failure > gear failure > unqualified source > failure to prequalify:  ROOT CAUSE                 

  This case is fairly transparent, but most of the time the root cause of failure is elusive, and it takes detective work to get to the source of the problem. It could require a cycle of analysis / testing / re-analysis, etc. In most real world situations it requires a team effort to clear up a problem. It’s worth every effort because the future of the company and jobs is at stake. It is not for the faint hearted.