Time for a change?

Zuken's specialist application engineer, Jeff Taylor-Jackson explains how the company's electrical E³.series E-CAD software can help save time and reduce risk by managing change in complex electrical aerospace projects.

While there is zero tolerance for error when it comes to getting the change process right in the electrical design process of complex aerospace projects, the reality is that failures can and do occur. Being able to get projects back on track can be very time-consuming and risky. How can engineers and project managers deal with unexpected problems in the most efficient and time-effective way?

As with any good design process, the analysis of potential failures or failure modes is a prerequisite. This is normally performed by using Failure Mode and Effects Analysis (FMEA), which attempts to prioritise the failures into seriousness and the degree of impact it has. Also, the analysis tries to predict the frequency of the failures and eliminate later detection during the manufacturing process.

Should a failure be detected, the decision has to be made whether it is due to the design, manufacturing process, or fatigue. The priority should be that the design does not change, and if modification is necessary then the design should be amended in one place at any one time, to provide time to test and analyse the effect of the individual design change. Should a design be manipulated in too many different places, there is potential for failures to develop faster than engineers can detect them. This methodical approach ensures a more reliable product output.

Methods of detection

How do you detect a failure during the manufacturing process? One method is to use failure testing, which involves testing a product to destruction to ensure that it will not fail under extreme conditions, such as mechanical stress, temperature, vibration or electrical stresses. Then continual failure testing, even after a product is developed, ensures manufacturing processes are as optimal as possible and improves the product.

In the case of failure testing, when the product or a component fails, examination should reveal what caused the failure. This will help to improve not only the overall products reliability, but also improve the manufacturing process.
Accepting failure in parts of the product development process and implementing a design process that allows you to easily and efficiently overcome these is critical. If a design failure occurs in a component used in a large project, the time to search every instance and update it with a new component can be very significant. It pays to have a design documentation structure that allows you to capture all instances of a given component and update them all at once.

In a large and complex project there will inevitably be huge amounts of documentation in the form of design schematics, test and validation procedures and results. A failure - or change - anywhere in the design or process will involve all departments involved with the product or project. In effect, the whole manufacturing process would have to start all over again.

Engineers need to be able to manage this change in an efficient way. If one single component failure has been detected, how does the engineer know where else in the design that component is also used? Maybe that component is part of an assembly and the design elements could be placed on many sheets in the design. The engineer shouldn't have to search through hundreds of components or sheets to find where the component occurs. What the engineer needs is a design tool like Zuken's electrical E-CAD software E³.series, i.e. object oriented so that the tool should easily identify the component by its class, attributes, or data model. Any change made anywhere in the design will then occur on every instance throughout the design.

www.zuken.com