There is no way around the use of simulations in the development of plastic components. They are optimized with practical tests. Technology & Innovation (T&I) is making a crucial contribution to a project to refine a Freudenberg-developed digital simulation tool used in the development of thermoplastic parts. Toolmaking at Laudenbach, Germany, played a key role in the process.
The use of plastic is on the rise. The trend to lightweight design has been clear for years, and electric mobility is now giving it another boost. Lightweight thermoplastic components are replacing heavier metal counterparts and increasing the range of e-vehicles. Complex plastic parts also have the ability to combine multiple functions into a single component. Housings are often made of plastic. The parts often provide sealing protection, shield electronics, and take measurements with integrated sensors. They also offer cost advantages, especially at high volumes.
With its special plastics lab, T&I has enhanced the expertise of Freudenberg Sealing Technologies (FST) for the development of new plastic solutions. The core of the effort is an advanced injection molding machine for the production of near-series samples and test specimens. Its special feature is an FST-developed master mold system. “We don’t have to produce a complete tool for every new test specimen. The master mold always stays the same. Only the mold insert varies, which means we are only changing component-specific cavities. This allows us to accelerate and reduce the cost of tool design and manufacture, benefiting the entire development process,” said Matthias Hauer, a specialist in plastics processing at T&I.
Forecasting Operating Life
In this case, the pieces are called multiload test specimens, and 150 copies have been produced. One of the process’s unusual features is that it was developed solely for internal purposes and not for an external customer. The client was Freudenberg Technology Innovation (FTI) as part of a “common project” that spanned several Freudenberg business groups. Above all, FST’S goal is to build up its thermoplastics expertise to the level that it has had in elastomers for decades – and develop plastic parts that are just as complex.
Digital simulations are a crucial factor in the development and design of plastic parts, especially for determining strength and durability. “You need a digital tool to simulate your materials in the component,” said Hauer. Reliable forecasts of a component’s useful life are the goal. The more precise a simulation model is, and the more fully developed it is, the more reliable the forecasts of operating life. The finite element method (FEM) comes into use here.
The 150 multiload test specimens developed and manufactured by T&I have the sole purpose of giving the Freudenberg simulation model a reality check. “Like a sparring partner, the parts provide verification of the predictions from the simulations,” Hauer said. The test specimens are pulled, bent, pressed, twisted, sometimes statically tested, and sometimes made to oscillate with increasing and decreasing swelling in dynamic tests. “The material characteristics, metrics and parameters then flow into the simulation model to optimize it. We are laying valuable groundwork. We need to have these kinds of meaningful simulation models in-house to design components that employ our new, uniquely developed materials and to develop new product groups and areas of application.”
The multiload test specimen (right) emerged from a tool manufactured in Laudenbach.
Mapping The Entire product Development Cycle
Hauer touched on one of T&I’s great advantages for such internal projects as well as those for customers. “For the development of plastic parts, we map the entire product development cycle from the idea to the part falling out of the mold – and we do it here. Our areas of expertise include materials technology, product development, production and process technologies. They span the entire value creation chain.”
The work has included cooperation on tool design with the FNGP Regional Office in Malaysia (MRO), whose employees are familiar with T&I’s master form system for injection molding machines. T&I’s own toolmaking capabilities are another advantage for plastic-part development. “The part geometry of the multiload test specimen, which has pockets and ribs, is complicated, and the tool is correspondingly challenging. Its production requires the entire range of mechanical processing. So it is all the more remarkable that it worked right from the start: the very first test specimens came out of the mold without difficulty. The team in Laudenbach really did a great job,” Hauer said.
