“Change is good” and “Change is a part of life” are two frequently repeated platitudes. However, for engineers, ranging from product designers to quality-assurance specialists, change can cause massive problems, and these are usually unanticipated and challenging ones.
As soon as an automotive component is designed-in and the total product is completely vetted, the last thing a vendor expects is to receive reports of field failures. Locating the root cause of the issue is frustrating, time-consuming, and expensive in terms of both the money and hours spent—that is evident. But what if the root of the problem is not a manufacturing or design fault such as incorrect mounting or adhesive curing, but a small, probably unremarkable change in a supplied component?
It is a known fact that cars have extended life these days; the average life of a car on the road in the United States is 11 years. Although a car of that vintage is not likely to be failure-free, a component problem can manifest itself early on, such as in the early-on three-to-five-year window, while a vehicle is still in the warranty period. Much worse, certain failures can result in mandated recalls even if the vehicle has crossed the warranty period.
How to Deal with Unavoidable Changes in Passive Automotive Components
Since change is unavoidable, together with the hazards involved, the automotive sector and its component suppliers have formulated standards and procedures for evaluating the effect of even the slightest changes to a component, by building on the preliminary design-in qualification standards. The AEC-Q200 qualification matrix for inductive products (magnetics) (shown in the table below) reveals the level of detail and meticulousness in the assessment that any change demands.
Even an apparently insignificant change in the base materials, fabrication, processing, or test of a component can have an impact on dependability, usually in unexpected ways. These changes could be down to production changes, logistics issues, the determination to lower costs, or even a customer’s request for enhancement in one or more performance specifications.
Moreover, the industry-wide transition to lead-free components in recent years, compelled by the RoHS and REACH directive, meant that numerous components with long histories and firm track records had to be re-qualified to AEC-Q200.
The AEC-Q200 standard defines where a stress test should be opted for because of a variation in process, materials, or design. Keep in mind the cautionary note at the top: “For a given change listed below, the supplier should justify why a suggested test does not apply for the given part(s) under consideration. Collaboration with their customer base is highly recommended.”
Certain automotive customers follow a substitute to the AEC approach, instead choosing the similar German-based ZVEI (Zentralverb and Elektrotechnik- und Elektronik industrie e.V.) standard. Their “Product/Process Change Notification Method in Automotive Electronics” offers an official set of notification brochures and forms part of the Product and Process Changes Notifications (PCN) procedure.
Regardless of the reason for the alteration in a passive component, there are proven, formal procedures for guaranteeing the impact is plainly understood, and is, with a bit of luck, zero or minimal. As electronics progressively permeate the design and operation of automobiles and vehicles, the need for passive automotive components is also increasing at a significant rate.
Regardless of the extensive use of custom and application-specific integrated circuits (ICs) and discrete active devices at the center of several of these vehicle functions, there is no alternative for what these passive components—capacitors, resistors, and magnetics—do as part of a circuit’s functions.
That is why any variations in their design or fabrication are carefully evaluated in relation to both long-term reliability and elementary performance specifications. Consequently, the industry has set up tough procedures to document and itemize the effects of even small variations to these less-glamorous yet essential components.
This information has been sourced, reviewed and adapted from materials provided by TT Electronics plc.
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