“Mind the Gap: Fill it with Testing.”

That’s the advice on Testing within collaborative development projects from Andrew Newton, MD at Magnet Schultz Ltd.

 

Here’s Andrew’s article for respected engineering publication, Control Engineering.

As an astute outsource partner for electromechanical development teams, we supply specialist technology expertise, typically to customers for whom this function of their development project is just one small part.

Our collaborations usually proceed smoothly from the outset with prototype designs sailing through the test process. But occasionally, a test initiative will reveal something vital. Take some recent projects: a powerful access ramp solenoid bolt on a hovercraft; an ingenious locking mechanism for cash-in-transit security cases; and a lock for a fridge onboard a prestigious sports boat. In each case, our engineers created a specification from the customer’s brief. That brief included all known aspects of the application: operating environment, life expectancy, etc.

Solenoid functionality is often oversimplified. We’re experts, so a gap between our understanding and the customer’s is to be expected. From experience, we recognise gaps in the brief and draw out requirement details: things like FMEA and risk-based analysis. But we can’t imagine every eventuality – which bring us to testing.

Testing is the one development process that shouldn’t be underestimated. It needs to be taken seriously. The danger of testing inadequately or in a way not representative of the application is that system limitations or weaknesses may not be revealed before production parts are ordered and installed.

When our customers engage with us, they get testing as part of the development support package. Initially, it’s a lab bench test. We can soak test for the million cycles required by the spec, confirm voltage ranges, check power consumptions or verify solenoid stroke forces meet the spec. But we cannot replicate the end-use environment – and that’s critical.

Real-life testing fills the gap that inevitably arises during development – that gap between our deep and practical knowledge of solenoid and actuator capability, and the customer’s understanding of the challenges faced in the application’s environment. When collaborative testing is undertaken thoroughly, it brings both parties together in an exercise that everyone understands. We often uncover things we would’ve liked to know sooner but forgot to ask, or that the customer neglected to mention.

In the sports boat example, we designed a robust electric lock mechanism for a drawer-style onboard fridge. Bolt strength was a key feature. We couldn’t quantify the true forces in the lab, and nor could the customer prior to taking the craft to sea. During the real-life test (a sea trial) with the boat wound up to around 50 knots, our prototype lock gave way under the pounding of the hull over the water. The test resulted in a stronger bolt design, meaning that all production craft are fitted with a proven lock that protects the owners’ refreshments at sea.

With the cash-in-transit case lock, our ingenious design met stringent usability conditions, delivered the impregnable security required and exceeded all criteria in the brief. The live test programme comprised extensive field trials with security operatives using the new case, fitted with pre-production lock units. Reports soon surfaced of some cases springing open when dropped. That G-force hadn’t been factored into the brief, but careful planning and execution of the field trial picked it up. We were quickly able to put it right.

Sometimes an application’s environment can change through unexpected third-party behaviour. During sea trials of the hovercraft, it was noticed that the maintenance crew routinely sprayed everything visible with a Waxoyl-type substance to inhibit corrosion. It began to clog the solenoid locking bolts causing them to stick. (Ironically, our stainless-steel design is corrosion resistant and doesn’t need coating – that’s an obvious requirement for constant salt water spray exposure). Thanks to the test, we could prevent that occurring by advising the maintenance crew and recommending new procedures.

MSL is a service company. We like to roll up our sleeves and go out on-site to observe and advise on live test procedures: that’s where we learn the most. There’s no charge – our goal is to make things work and we know how to do that properly. When customers augment our bench tests and engage with us for real-life testing, we work together to sign off the design and get the production product right.

I’m certain these experiences parallel those of other specialist outsource partners. My advice to the customers of those expert companies is to Mind the Gap: recognise that collaborative testing is vital and make use of all the test expertise on tap.

Andrew Newton, MD of Magnet Schultz Ltd.