How to make 12 million pistons a year

I love a good factory visit, and yesterday’s visit to the Federal Mogul facility in Nuremberg was very good.

The factory opened in 1924 and now produces 12 million pistons a year for the likes of Audi, BMW, Mercedes and Porsche.

Every piston starts with molten metal, so there’s a lot of melting in a lot of furnaces. Every day Federal Mogul melts 60 tonnes of the stuff to 830 degrees in seven gas-fired furnaces for casting in the foundry upstairs.

It’s rather incredible to stand next to several hundred kilos of molten aluminium and feel the heat as deft robots collect the material in crucibles and pour it into the molds.

Of the 36,000 pistons that are cast here each day, 80% are for diesel engines including those for BMW’s six-cylinder 3.0-litre diesel. This, we are told, is the most stressed piston in the world.

Once cast and cooled, the machining lines await. The multi-stage process takes around twenty minutes and creates ultra-smooth surfaces, precise combustion bowls and carefully located cooling galleries around the top of the piston.

More nimble robots whir and spin in a dizzying dance that carefully passes each part down the line. A piston is produced every every 14 seconds, seven days a week.

For those destined for life in engines working at high temperatures and pressures – up to 400 degrees and more than 200 bar – the edge of the combustion bowl is also re-melted with a TIG process that Federal Mogul calls DuraBowl.

This reduces the size of the particles in the metal by ten times and improves lifespan by between four and seven times.

Every single piston is subjected to a battery of non-destructive tests on the line, including UV scans which look for correct gallery position and near surface defects. Coating thickness and tolerances are measured on each, while a final six lines weed out any other imperfections.

The Nuremberg tour came off the back of a conference that the $6.9 billion company held to look at the solutions to the challenges presented by engine downsizing and what they mean for the aftermarket. Look out for that on Catmag.co.uk, and in CAT Magazine, soon.