Problem solutions

Citation

Loughlin, C. (2006), "Problem solutions", Industrial Robot, Vol. 33 No. 2. https://doi.org/10.1108/ir.2006.04933baa.001

Problem solutions

Problem solutions

In recent years there have been a few notable failures in composite structures in the yachting press. One was a revolutionary design of catamaran that was sponsored by Philips and headed up by Pete Goss, and more recently a series of cruising yachts manufactured by Bavaria.

The Philips' catamaran went through a number of well publicised disasters before finally falling apart in the North Atlantic while the Bavaria yachts suffered the catastrophic and in one case, fatal, capsize and sinking when the keels fell off.

Whether these problems were caused by faulty design or faulty construction I do not know. Probably it was a combination of both – perhaps a design that did not allow enough for normal manufacturing variations or manufacturing variations that were simply too great.

Both serve to highlight the difficulties in composite manufacture. If you have a vat of molten metal or plastic and pour it into a mould then, provided you got the basic ingredients correct and let it cool at the correct rate, you can be pretty confident that the resultant material will behave itself. However, in the case of composite fabrications that are built up of numerous layers, and in many cases applied by hand, then the opportunities for the introduction of faults are legion.

Delamination is one of the more common defects; another is thickness variation and inhomogeneous variations in the mixture of resins and fibres.

This all sounds like bad news for the composites industry and indeed it is, but composites structures can also be fantastically efficient and display strengths and strength to weight ratios that are pretty well impossible by other means.

So composites are here to stay and we need to overcome their occasional deficiencies as we would any other engineering problem. The biggest source of error is manufacturing variation and one way to make progress in this area is by the use of automation. Consistency and automation go hand in hand. Automation is only possible if your component parts are consistent, and consistent high quality products can only be made using automation.

However, although automation can give you consistency it cannot guarantee you quality. If you consistently do something wrong then your only cause for solace may be that at least all your parts will fail in the same way.

Carbon fibre, Kevlar, glass and epoxy resins are all wonderful materials but their individual qualities should not blind us to the care that needs to be taken in their application.

It is not sufficient to simply automate a process that is currently performed manually and expect all your problems to go away. Anyone who has ever worked with glass fibre and resins would agree that it ticks all the “Dirty, Dull and Dangerous” boxes and is crying out for robotisation, and I would encourage companies that are still doing this manually to consider automation – however, as with any problem the correct solution is born from a thorough understanding of what caused the original problem. If the problem is delamination caused by insufficient resin then simply adding extra layers only serves to hide the problem even deeper.

Clive Loughlin