Virtual dimensioning of challenging LSR processes
Sigma Engineering Hall A5 Stand A5-5105
At Fakuma 2018, the German company Sigma Engineering GmbH, Aachen, will present in a joint project the real and virtual production of a complex silicone part with EMDE MouldTec GmbH and Momentive Performance Materials GmbH. The focus is on the early design and optimisation of mould and processes. Sigma accompanied the whole development process of the pot cloth and assisted to determine the ideal configuration for production.
At the trade show, Sigma Engineering will demonstrate the latest application of its Sigmasoft Autonomous Optimization. As a consistent further development of the Sigmasoft Virtual Molding technology, Autonomous Optimization not only offers users the opportunity to perform virtual design of experiments (DoE), but the software also determines automatically the optimum process configurations to achieve the given target: e.g. short cycle time or balanced part filling with low pressure requirement, with the help of a fully automatic optimisation.
The capability of the technology was used during a joint project with Momentive, Leverkusen, Germany; EMDE, Oberbachheim, Germany; Wittmann Battenfeld GmbH, Kottingbrunn, Austria; and ACH solution GmbH, Fischlham, Austria, for the design of a pot cloth from LSR (liquid silicone rubber). In the process, the simulation was used alongside the whole development of part, mould and process starting from the part design phase. In the further course it helped to answer important questions, such as what is the optimal connection via the cold runner or how to design an appropriate heating cartridge concept to achieve a homogenous temperature distribution.
The pot cloth is a complex part with a shot weight of 95 g and a flow length of 135 mm with a predominantly maximum wall thickness of 1 mm. A uniform part filling without the premature start of a curing reaction is therefore critical to part quality. Due to this fact, at first the number as well as the best positions for the cold runner nozzles were determined in a virtual DoE. With this approach any number of variants can be calculated in a single simulation and afterwards can be compared and evaluated on the basis of predefined target values, e.g., pressure requirements and risk of air entrapments. In the further course of the project, not only the ideal process settings were determined with the help of Sigmasoft Virtual Molding, but also the complete heating concept of the mould was optimised. Based on the results of the virtual analysis the mould was then built by EMDE (stand A4-4307).
At Fakuma 2018, interested parties will not only experience the complete design and virtual production at the Sigma stand, but will also be able to follow the real production of the pot cloth. The realised mould will run live at the Momentive stand A4-4307. It will be produced with Silopren LSR 2650 on a Smartpower 90/350 Unilog B8 machine of Wittmann Battenfeld (stand B1-1204), who also provide the handling system. The mould and cold runner block from EMDE are combined with a pump and mixing unit MaxiMix 2G from ACH (stand A4-4307).