Sealing technology forms a critical component for many applications across multiple industries. From engine gaskets in automobiles to hydraulic systems in airplanes to medical seals in healthcare, seals play a versatile range of essential functions that make an array of technological achievements possible. These achievements in turn depend on sealing technology, which is always advancing through research and development to keep up with the needs of the various industries it serves. Here are three recent innovations in sealing technology that are helping promote important advances in other fields.
3-D Printing
One of the most significant recent innovations in sealing technology is the way seals are made. O-rings, for instance, have been produced through injection molding, which involves injecting hot material into a mold; or compression molding, which involves placing the material in a mold and then subjecting it to heat and pressure. Both of these methods are considered subtractive manufacturing, meaning that materials are formed by cutting away from raw material, resulting in significant waste and expense.
Three-dimensional printing in contrast is an additive process, where the printer adds the material in layers until the final product is formed. This reduces waste and cuts costs, while speeding up the prototyping and production process. Additionally, because 3-D printing works from a digital blueprint with a printer, virtually any substance can be used as printer ink, and products can be printed in any shape or size. For instance, o-ring manufacturer Apple Rubber is able to offer over 8,000 sizes of o-rings in stock, made from numerous customized rubbers such as Viton, nitrile and fluorosilicone, suitable for use in specialized applications such as automotive and aircraft engines and medical seals. The application of 3-D printing to o-ring production is helping propel the global gaskets and seals market to a compound annual growth rate of nearly 5 percent, putting it on track to gain $11.29 billion in incremental growth between 2017 and 2022.
PTFE Radial Shaft Seals
Another important innovation in sealing is the emergence of radial shaft seals (rotary lip seals) made from polytetrafluoroethylene (PTFE), better known as Teflon. Made from fluorocarbon, PTFE has a low-friction coefficient that gives it a characteristic nonstick quality. It is also resistant to changes in temperature, electrical effects and corroding reactions.
These properties prove useful when sealing objects that rotate, such as shafts and bores. In this type of seal, the seal has a lip on its inner diameter to fasten onto the shaft, along with metal casing on its outer diameter to press into the bore for an interference fit. A gasket is placed between the can and the layers of sealing lips in order to prevent leaks. Using low-friction PTFE for this allows the seal to function at higher surface speeds than would otherwise be possible.
FFKM Sealants
The sealing industry is also benefitting from the development of sealants made from FFKM, popularized under brand names such as Kalrez. The chemical structure of FFKM includes more fluorine and less hydrogen than other fluoroelastomers. This raises its ability to resist temperature and chemical conditions, combining the strength of elastomers with the chemical stability of Teflon. FFKM can resist temperatures up to 600 degrees Fahrenheit, and can resist corrosive chemical effects that would damage most elastomers. It also resists deformation from continuous load strains better than Teflon.
These qualities allow FFKM to be used for aerospace applications involving conditions that would be too extreme for other materials. For instance, FFKM has been adopted by jet manufacturers to provide sealant for gearboxes and bearing chambers.
FFKM sealants and PTFE radial shaft seals are two examples of how innovative materials are allowing an expanding range of sealing applications. Three-dimensional printing is making it easier for manufacturers to produce sealing devices made from these and other high-tech substances. Sealing innovations such as this are empowering manufacturers to explore new applications that were not previously possible, laying a foundation for future breakthroughs.
