I am a massive believer in the application of 1st Principles, particularly when it comes to machine breakdowns and faultfinding. It has rescued me time after time on all sorts of problems, in all sorts of places.

One of the first elements is being sure of exactly what the machine is supposed to do. There have been occasions where I have been asked to consult on a machine problem and have found that the ‘problem’ is actually something the machine isn’t designed to do. I might be able to enable it to do so but that’s a different story.

So number one of my 1st Principles is to assess exactly what the machine is supposed to do. Secondly is to observe in detail what it is actually doing. There are all sorts of pressures on those with day-to-day responsibility for a machine. They can be production targets, impatient management or a, not too uncommon belief, that machines are possessed by spirits and can be fixed by some bizarre combination of actions that only make sense to people under pressure. This all leads to clouded judgement about the real nature of the problem and where an independent view can make the difference.

I was asked recently to visit an Irish bottling plant that was having problems with one of their machines. It had been working perfectly well and then suddenly went wrong. Here I spent the best part of the first morning observing the machine going through its paces and checking the diagnostics. The key components were a motor, gearbox and associated tooling.

The first step was to take off the motor and test that separately. Does it work? Does it do what we expect it to do? If it doesn’t then adjust until it does so we know then that that component is not the problem. Next we attached the gearbox that again needed some adjustment before it was conforming to spec. Then we added the tooling, which again after some adjustment, was working to spec. Having given these components a clean bill of health we remounted them on the machine and tested it. It failed. Now the task was to identify what was different when mounted on the machine. The answer was air pressure. This was confirmed when the machine was run without air and performed to spec.

Having identified air as the problem we then focussed in on when and where the problem was caused. We identified this as being when the tooling gripped a bottle cap as part of the process and when air pressure in the system was at its peak. This was causing a seal to leak air preventing it consistently reaching the operating level. It was then revealed that the seal had been replaced shortly before the problems started. The currently available seals are of a slightly different spec to the original. The answer was a slight reduction in air pressure and the machine performed as required.

These are 1st Principles in practice.
What is it supposed to do?
What is it actually doing?
What has changed?
Is the expectation correct?
Step by step test and correct until the fault is flushed out.

© 2012 Tim Oxtoby Ltd / Terms and Conditions