WEINHEIM, Germany—Freudenberg Sealing Technologies has developed a seal that can monitor its wear, measure forces and perform other functions by arming it with magnetic properties.
The firm's smart seal integrates a conductive filler material into its elastomer mixture or a microchip into the seal. The first makes it possible for the seal to be used as a sensor or actuator, as rubber in its pure form cannot process signals.
Freudenberg stressed that regardless of what solution is used, the basic sealing properties are not compromised. Its smart seal still maintains a high tolerance for temperature fluctuations and a good media resistance, so its primary sealing function is not impaired.
“In some industries like the process industry, they want to make sure that there are no contaminations from small pieces of rubber that wear off during the application into the goods being sealed,” said Boris Traber, head of advanced material development for FST.
“So this is an area where these kinds of sealing materials could be used and potential contamination tracked with an X-ray. But it is important to remember the primary function is a sealing function, and additionally it can be detected by X-ray.”
Demand for sensoring has existed for awhile. Traber said the firm has spent the last 15 years compiling its portfolio. Because industries such as automotive, oil and gas, and food processing demand more self-communication systems, the company projects that demand for these kinds of materials will continue to increase.
Traber said the firm is looking at all industries, with more direct demands from the general industry. However he added that Freudenberg is presenting the potential of this technology to an automotive customer.
“We think that sealing can also play an important role in this development since the sealing decides whether the system leaks or not, and this is very important to the function of the entire system,” Traber said.
He said the firm can vulcanize a sensor into the sealing material, and that sensor could have many possibilities—ranging from data storage or any list time prediction. The second way would be to co-vulcanize sensors into an existing product—for instance a sensor in the plug and seal.
He added that because Freudenberg develops and mixes its own materials, the firm has developed a portfolio of materials that can be used as smart materials, including permanent magnetic, magnetizable, electrical conductive and di-electrical.
The key challenge, though, is balancing loading the material with fillers without losing the sealing properties of the elastomer. Traber said that while loading more filler increases the electrical conductivity and magnetism properties of the seal, at the same time the sealing properties of the elastomer worsen.
Determining which materials are chosen is a matter of product design and application.
“The trick is to get both properties optimized,” he said. “We have some options from the compounding side that will already allow us to optimize some properties. On the other side, we need to know the final application to know which properties are important and which ones can be neglected.”