My two pence

Let’s assume the new material is behaving itself, in the mechanical sense. Let’s also assume you are in luck, and that the aesthetic appearance of the material is the same as the old – a dull matte black. Of course, you can’t just have a hard stare at it yourself and declare that it’s good to go – you will need objective colorimetry and reflectivity or ‘glossiness’ measurements. You will also have to get a sample part blessed by your friendly design department, with their finely calibrated eyeballs signing it off against the original master plaque of Dull Matte Black #57A….

So the new part works, and it looks good. To make sure that it keeps on doing both for many years to come, you now need to navigate an obstacle course of testing that makes the Twelve Labours of Hercules look like a fun day out. Chemical resistance to every fluid you might imagine and a few you might not; resistance to UV degradation and scratching. Washing machine resistance – yup, it’s a key fob, remember. It will definitely, definitely, be forgotten in a jeans pocket and thrown into the wash. Drop tests. Thermal cycle tests. Salt spray tests. Dust resistance tests. Heat and vibration tests; you get the gist…

Have you got the test reports for all these, duly signed off by the supplier(s) and filed away in the right archives to ensure document traceability in a decade or two? Terrific. Let’s continue.

Now, how about radio performance? The key-fob is a mini radio transmitter after all, and the new, cheaper, plastic may not have precisely the same RF or radio-frequency permittivity (yes, that is a word, I checked – ed) as the old one. So you need to arrange a battery of RF tests in an electromagnetic chamber. And by the way, this is a regulation item: the results have to be submitted to the authorities that control the air-waves – in every region or country where the car is sold. Lots and lots of paperwork.

Oh, speaking of regulations, did you remember to check it’s REACH compatibility? Yes, the sparkily named Registration, Evaluation, Authorisation and Restriction of Chemicals law? Ooops. Better get on to that. This is the legislation that restricts the use of nasty elements like lead, hexavalent chromium (familiar to anyone who’s watched Erin Brockovich) and vinyl chlorides, and you need formal certification from the Tier 2 supplier that they have not used any of these nasties in making the new material. More documentation…

Now that you’ve got it working, tested it to death and knocked down a couple of forests in certification documentation, surely you can pull the trigger on this bloody change? Not quite. You’ll need to think about part interchangeability and modification synchronisation.

Excuse me?

Interchangeability is pretty simple – it’s whether the new part is compatible with the previous one. It comes in two flavours – forwards and backwards compatibility. Forward compatibility means that the new part – let’s call it ‘B’ – can be applied to all cars from now on…but it will not function on older cars, built with original part A. So both parts A and B need to be maintained in production, to service older cars.

Backwards compatibility means that new part B will work with all cars: the existing fleet, and those yet to be built. The supplier can then phase out part A and simply replace it with B from now on. Make an error on this detail and you may not only stop a whole production plant – an expensive, not to mention career-limiting thing to do – but also create a huge problem for potentially millions of cars already on the road. Not too tricky in the case of our little key fob example (it’s almost certainly backwards-compatible) but mind-numbingly complex in the case of parts like electrical wiring harnesses or instrument packs.

Modification synchronisation, however, is most certainly an issue that you, key fob guy or gal, must consider very carefully. Because your part does not exist in isolation. Its radio signals are picked up by antennae connected to the BCM or Body Control Module, which in turn communicates with the car’s engine control unit and immobiliser systems. These systems all share a distributed, unique key-code as part of the car’s security system, and hence form what’s known as a ‘matched set’: any modification to one needs to be accompanied by matching changes to all the others in that set.

And get this – these linked modifications must happen not just vaguely in the same month or week, not even on the same day or hour. They must happen precisely in the 55-second window when a single, very specific vehicle enters the production line – the car with the VIN number that will forever mark the ‘before’ and ‘after’ of this modification. The logistical magic required to manage this defies comprehension. This is the work of your colleagues in Production Control and Logistics – there are more of these unsung heroes of the automotive world who deserve stories of their own on another day.

Long story short, you need to phase your Design Change Approval with various other colleagues. To get your £0.02 cost saving, you will need to persuade them to raise matching, synchronised modifications, and work closely together to make sure they happen at precisely the same time.

Believe it or not, I’ve actually skipped a lot of detail here. I’ve glossed over the endless meetings and financial calculations. I’ve mercifully spared you the tedious administrative detail of the actual sign-off and approval processes.

Oh, and I also glossed over who gets the two pence saved. Well, in an ideal world, if you work for a half-way ethical car company, it will get divvied up. A little sliver will hopefully go to the supplier whose idea it was, to encourage them to come up with more of the same. Another sliver will go to us, the end customers – not directly in reduced sticker prices, mind, but indirectly in the form of more equipment and higher specs on future models. The rest will go into the car maker’s coffers to shore up their – probably low single-digit – profit margins.

And you? Well, you get your paycheck, a pat on the back from your boss if he or she remembers to do so, and the satisfaction of having successfully modified a part that no one will ever know or care about: except you. Every time you pick up one of those modified key fobs, you will know that it’s got a tiny bit of you in it.