Agreement and argument

Ray Bardsley, head of sales & marketing at SMC Pneumatics (UK) brings his own perspective to the propositions and pitches.

Engineers must look closely at the total cost of ownership. Building a machine cheaply will no longer impress a customer if it translates into costly running that wipes out any savings in months.

It is also true that fitness for purpose is most important. Quality is always worth investing in, but over-specifying is not. It may put a smile on a salesman’s face. It will not satisfy your customers.

There is no need to buy `the best’, if by that you actually mean better than the application requires. The criteria for selecting the most appropriate equipment include long-term considerations – reliability, maintenance, and energy costs.

So do not compromise on quality, but do not overspecify; do all the calculations to reach the right decisions. This means not taking figures in isolation. Can lowering filtration standards really yield a saving of £50/cylinder/year? Without seeing the detailed calculations, it seems unlikely! Even if there are savings, they need to be put into context, specific to your application.

Most manufacturers would seriously question anyone recommending lower filtration standards in order to save money. Why have the vast majority of pneumatic manufacturers world-wide selected 5 micro m filtration as standard?

Not because they are out to make a fast buck – the capital cost of 5 micro m filtration is comparable to 40 micro m. And not because their equipment cannot cope with lower standards of filtration. Many components operate reliably even with poor filtration – for example, most SMC cylinders and valves can operate in suitably dry air filtered to 40 micro m.

So why the international standard of 5 micro m? Reliability. Even if 40 micro m filtration may save money on energy, it can definitely lose many thousands in extra maintenance and unscheduled line stoppages. True, 35 micro m particles might not interfere with the operation of some of your cylinders, but what about all the other components? Valves and instrumentation could be at particular risk. Why unnecessarily incur the likelihood of breakdown?

Major compressor and drier/filtration manufacturers have focused product development to produce clean dry air for line filtration below 20 micro m, which makes choosing to spend money on fitting 40 micro m filtration seem a rather perverse decision!

Why prejudice your calculations towards 40 micro m? To select a filter properly, the first considerations are input flow and anticipated pressure at the filter. Then, taking into account all the equipment and piping being installed in line after the filter, determine the range of maximum allowable pressure drop and finally the pressure required by the cylinders at the end of the system. Then you can select a properly sized filter with the correct allowable pressure drop, and assess the tolerances of all the components. To try to introduce 40 micro m filtration as a preferred option into the calculations any earlier is not good practice.

We would also challenge the notion that engineers should invest more in diagnostic products. Diagnostic capabilities can be valuable – but whether it is cost-effective or not, in terms of both capital investment and lifetime ownership costs, depends on your specific application.

`Intelligent’ products carry a premium that is well worth paying for some applications. However, choosing to pay over the odds for diagnostic components as an insurance policy because you have introduced problems from poor filtration hardly seems an `intelligent’ solution!