Pöppelmann K-TECH® has recently started using injection moulding of 2-component liquid silicone rubber (LSR) for components with very high sealing and temperature requirements. The process shows excellent properties in the compression set test, as well as good weathering, ageing and UV resistance. This fully automatic process is recommended for high production volumes and high economic efficiency. Because LSR is so robust, it is an optimal solution for use in battery technology of electric vehicles, which requires very high temperature-resistance and reliable protection against moisture and chemicals.
The 2C LSR technology enables moulding of different materials onto each other in one reliable and fully automatic process. For this production process we use a high-precision tool with different temperature levels for the hard component (thermoplastic) and the soft component (LSR). Precise temperature control ensures that the silicone vulcanizes at the optimum time and that both components form a covalent bond. No further assembly steps are required.
The changeover from several processes to a fully automatic, single-stage process not only saves time, but also achieves a particularly high level of economic efficiency at large quantities.
Our K-TECH® team carried out a Quick Check in the beginning of a joint project in the field of battery technology – a component housing cover for a rectifier – for a long-standing and well-known customer in the automotive industry. Our review showed that the use of the innovative LSR process leads to the best possible solution because LSR seals reliably even at high temperatures of up to 250°C without problems.
With regard to the process flow for the component housing cover, a number of improvements have been achieved using the 2C LSR process: In a single-stage production process, the LSR seal replaced the bonding of six separate silicone pads, which was previously necessary. The chosen combination of materials enabled the required chemical bond between thermoplastic and LSR. As for the hard component, an improved material selection was also able to minimize warping.
Overall, we were able to shorten production times and reduce costs. Thanks to automation, the project was characterized by high process reliability and high technical cleanliness. The optimized design also contributes to noise and vibration reduction.