Apr 11 2013
Oil spots on the driveway are largely a thing of the past, thanks to advanced elastomeric sealing materials.
But changes in powertrain technology, lubricants, durability standards and consumer expectations are driving new compatibility requirements in today's cars and trucks, and Freudenberg-NOK Sealing Technologies (Freudenberg-NOK) is at the forefront of helping its customers navigate this evolving material landscape.
Two Freudenberg-NOK materials experts will participate in 2013's SAE World Congress April 16-18 at Cobo Center in Detroit, Mich., and discuss the challenges associated with today's advanced industrial materials. Dr. Sai Sundararaman, scientist specialist, Technology, will present the results of an organizational study evaluating the effects of temperature on material wear. Joseph Walker , director of Material Development and Chemical Regulatory Compliance for the Americas, will discuss emerging material compatibility issues during a roundtable forum with industry experts.
"Advances in vehicle technology have made material compatibility absolutely key today," Walker said. "Rubber component manufactures incur risk every time their materials are subjected to new fluids. Compatibility is really about management of risk. In fact, the very definition of 'compatibility' needs to be challenged since it is dependent upon application and design and is about functional intent. It's no longer about standard evaluation methods."
Indeed, standard materials compatibility testing – the "dip and dunk" process of emerging components in lubricants to analyze how their properties may respond over time – are no longer robust given today's advanced powertrains and transmissions that pack smaller spaces with electric motors and multiple gear packs and clutches. New axle technology – the result of rising consumer preferences for all wheel drive vehicles – also present harsh new material challenges.
"The enemy is heat," Walker said. "Today, we are packing so much into power transfer cases that you may only end up with a cup of lubricant. We need to know how materials will respond to these new temperature extremes being generated in smaller, sealed environments."
Test protocols have not kept pace with advances in elastomeric technology and increased industry durability standards, Walker noted. And because they rely upon the use of factory-spec fluids, they may not accurately capture the real environmental challenges that critical sealing components face once exposed to the oils and coolants consumers routinely use in their vehicles. To further complicate the vehicle environment in which materials function today, alternate fuels such ethanol, methanol and compressed natural gas bring their own unique set of sealing requirements to the equation.
"Our goal is to supply our customers with a material that works regardless of the design and application challenges," Walker said. "But today's compatibility testing may not always guarantee a spot-free driveway because the measurements are too crude to take into account design and application uses.
"With today's virtual manufacturing, we actually have the tools such as FEA (Finite Element Analysis) to model the effects of design and application on materials. That's what Freudenberg is doing. We are studying where today's materials fall short and what we need to do to take them to the next level. We are doing this up front, upstream, before finished parts are dunked and dipped," Walker added.
Sundararaman's presentation will parallel Walker's in emphasizing the importance of controlling temperature during testing. Current ASTM 3702 wear test standard does not specify temperature control in test parameters.
"Material properties, especially for plastics, are temperature dependent," Sundararaman said. "So wear rates for engineered plastics are also temperature dependent. Temperature controlled wear tests provide an improved means of rating materials for wear performance and temperature control by ensuring that the failure of the thermoplastic material is due to wear and not melting. Freudenberg-NOK has developed a method for controlling temperature during wear testing. This will be a significant benefit to our customers."
The 2013 SAE World Congress theme is "Achieving Efficiency." Efficiency is essential to the success of the next generation of automobiles, the organization said. Understanding material compatibility issues, Walker and Sundararaman said, will play a critical role in achieving this efficiency. To lean more, please go to sae.org/congress.