Hairnets, gloves, cleanroom shoes and special anti-static clothing are all items I wear every day for my work. I don’t work in a canteen or an operating theatre, but hygiene is a basic requirement in my workplace – the 212 m2 cleanroom at Marklkofen. It has existed since 2009 and it is the largest cleanroom at MANN+HUMMEL. Work here is a bit of a mystery to many of our colleagues though. Seen from outside through one of the many glass windows, the work that goes on in the cleanroom can, admittedly, look slightly strange, with people dressed in white lab coats and hairnets moving gingerly from A to B and going about their business, entering and leaving the room through a type of airlock. What’s that all about?  

Special cleanroom conditions

Well, first of all it’s important to understand what exactly a cleanroom is. In simple terms, it is just a very clean room. The official definition, however, is rather more complicated: Depending on the requirement, only a set number of free-floating particles may enter the room. To ensure that this number is not exceeded, the supply air to the cleanroom has to be filtered. In our case, this means climate control and a constant air temperature of 21 degrees Celsius, as well as a need to keep the air humidity at the same level. Our ventilation system really has to be reliable. There is an overpressure of 15 pascals in our cleanroom. That means you notice a slight breeze when you enter the room as air pours out. This ensures that dirt particles don’t end up in the cleanroom. Ceilings, walls and floors all have a conductive coating.

More demands on suppliers

One of the reasons for us having cleanroom production is so we are able to meet the ever-growing demands for extremely clean products. In modern injection systems, for example, the high pressure at which fuel is injected can cause even the smallest particles to act like projectiles and damage the injection nozzle or block a line. That’s why we need complete cleanliness even at the stage when parts are being produced.

The same applies to our suppliers too of course. The individual parts are pre-cleaned and delivered free of contamination, being packed with several layers to start off with. The closer these get to the cleanroom, the more layers are unpacked, before finally reaching the production area suitable for a cleanroom environments. After installation, welding and final assembly, we ensure the modules are packaged in contamination-proof packaging before forwarding them to our customers.

Here at Marklkofen, we produce fuel filter modules in series. This kind of production process takes ten minutes per filter element on average. 20,000 parts pass through the cleanroom every day. We have a three-shift rota, with staff working from 23:00 on Sunday to 14:30 on Saturday. As you can see, working in a cleanroom provides both variety and excitement.