One of the many thorny problems engineers have faced in the design of mechanical packaging systems has to do with radial shafts. In order to ensure a consistent end product every time and eliminate waste due to damaged packaging or products, (which is after all one of the aims of mechanizing production processes in the first place), these shafts have to have a rotation which is entirely free of eccentricities. Eccentric rotation may be fine for planets, but in the manufacturing environment, it's nothing short of disastrous.
Shaft seals were the solution developed by engineers to eliminate eccentric radial shaft rotation, enabling many routine production tasks formerly performed by hand to be automated. These seals have allowed manufacturers to dramatically increase production outputs, reduce costs and save untold hours of manual labor in the process while also greatly reducing waste.
A well designed shaft seal needs to provide a perfect fit which not only maintains steady rotation but also prevents friction due to relative motion of these two parts. To the layperson, this may not sound like much, but it makes a great deal of difference - this friction can greatly shorten the life of shafts and shaft seals alike, cause a higher operating temperature on the production line, increase the energy usage of the process and even lead to burned products and small fires which pose a safety risk and necessitate the shutdown of the entire line while maintenance is performed. Shaft seals may be just one small part; but they're vital to the smooth operation of a wide variety of production processes.
