At Fakuma 2024, ELMET, the LSR manufacturer Momentive and Sumitomo (SHI) Demag joined forces in developing, producing and processing liquid silicone rubber (LSR). The result of this was the Drip Guard spoon holder that stops drips from landing on the work surface while cooking. The demo object will be produced live at the Momentive stand (A4-4307) and distributed to visitors as a useful give-away.
Key takeaways:
- The material is characterised by low viscosity, high reactivity and good mechanical strength.
- Momentive simulated the injection moulding process using Sigmasoft Virtual Molding software from Sigma Engineering.
- ELMET was responsible for the concept, design, construction and the TOP 7000 Pro dosing system.
- The Drip Guard tool is mounted on an all-electric IntElect 130 injection moulding machine from Sumitomo (SHI) Demag.
ELMET
The moulded part with a shot weight of around 55 g is made from the two-component liquid silicone rubber Silopren LSR 2670 from Momentive Performance Materials. The material is characterised by low viscosity, high reactivity and good mechanical strength. Thanks to these properties, it has established itself in applications with highly resilient parts in the automotive, electrical engineering and consumer goods market segments. Its adapted reactivity made it possible to reduce the curing temperature by around 20°C and still achieve consistent cross-linking.
Momentive simulated the injection moulding process using Sigmasoft Virtual Molding software from Sigma Engineering to determine and optimise the exact production parameters in advance. This involved carrying out filling studies and determining the required curing times at adjusted mould temperatures. The newly available specific material data of Momentive's liquid silicone rubbers also enables the precise prediction of the expected shrinkage behaviour of the moulded parts.
ELMET was responsible for the concept, design and construction. Injection takes place via a SMARTshot P valve gate cold runner system. A pneumatic drive ensures precise movement of the nozzle needle during injection of the liquid silicone rubber into the cavity. The nozzle of the SMARTshot cold runner system can be calibrated to precisely balance the filling process.
Also from ELMET is the TOP 7000 Pro dosing system, which sets a benchmark on the market with its precise adherence to the mixing ratio between A and B components and additives, as well as its exceptional cost-effectiveness. Thanks to the innovative pump unit, the amount of LSR located in the system is extremely low. This significantly reduces the cleaning volume when changing materials. Thanks to the optimised follower plate geometry, less than 0.4 % residual quantity remains in the drum, which has a particularly cost-saving effect. The drums are changed fully automatically (from the edge of the drum), which increases ease of use and reduces the amount of training required.
The Drip Guard tool is mounted on an all-electric IntElect 130 injection moulding machine from Sumitomo (SHI) Demag, which is up to 80% more efficient than hydraulic machines and characterised by its small footprint. Highly dynamic direct drives ensure maximum precision, and large bar spacing increases flexibility. Including an LSR machine package, SHI provides a complete solution for liquid silicone processing with LSR injection unit, robot, vacuum, heating, cooling and interfaces to peripherals.