Maintenance: surely one of the aspects of engineering most likely to conjure up the image of mechanics, wrenches, oily rags and overalls, and the whistling intake of breath through the teeth that heralds the conversion of the estimate into the final bill. Sometimes, though, it really isn’t the parts and it really is the labour.
Let’s make some sweeping generalisations about cultures, industries and design engineers. Let’s say, for example, that European cars are less reliable than Japanese cars, but are easier to repair and the parts are cheaper (1) (2). Let us also say that the same holds true for trains manufactured in Europe and Japan (3). Why do we think this (admittedly exaggerated) situation has arisen? The answer lies in whether you are designing a product for reliability or maintainability.
The Europeans like to design for maintainability. You assume that certain components are going to fail at some point, so you make sure you can replace them in the shortest possible time, with the minimum amount of people, and with standard tools. Your suppliers in turn make systems highly modular, so you can quickly replace the offending sub-system and get back to earning money with your valuable assets.
The Japanese, people would have us believe, design for reliability. If you invest in development and testing and have high levels of confidence in the performance of your components, why should you need to spend time designing easy-access covers and making sure maintenance technicians can operate comfortably in the equipment bays?
If you are in the business of providing complex equipment, take a moment to think where your company sits on the line between these two extremes.
Often it comes down to what the customer wants and what they are willing to pay for. When delivering large projects, a company’s experience from similar products, coupled with contractual requirements that specify minimum reliability performance, will drive them to either design a product that lasts, or one that can be easily repaired.
But things are changing. In the case of the Intercity Express Programme, there are contractual requirements for availability of the trains, but not an actual number of trains. This means the supplier can chose how many trains to supply, as long as the right number of trains are available to go into service every day. This only works because the supplier of the trains is also responsible for their maintenance for 27 years, and has to put their money where their mouth is. The procurement of the UK Search and Rescue (helicopter) service is set up in a similar way, with the emphasis on providing a service in the right time at the right place.
Engineers will increasingly have to balance the triple constraint of Reliability, Availability and Maintainability when working on large contracts. Depending on your company’s current philosophy, that might mean some significant changes, to make sure a technician can wield a torque wrench comfortably during maintenance.
In the case of my car, I just wish the headlights were slightly easier to replace.
References:
(1) author’s experience from owning a Dagenham-built Ford Fiesta Mk4 and a Japanese-built Honda Accord Mk7.
(2) JP Power survey 2012 - 5 of the top 10 cars are Japanese
(3) an experienced colleague’s summary from working on the Hitachi Class 395 and various European fleets.
