Elastomer molded parts with a consistent degree of crosslinking
The goal of the AiF project is to investigate the dielectric analysis method with regard to its ability to detect the crosslinking process during elastomer injection molding.
© IKVThe mechanical properties of injection-moulded rubber parts are largely determined by the degree of curing. Up to now, a qualitative or quantitative determination of the component properties is only carried out after production with a large time lag, during which rejects may have already been produced. A determination of the cross-linking state of moulded rubber parts integrated into the moulding tool as a new quality parameter can significantly minimise this risk. Dielectric analysis (DEA) is a method for determining the degree of cure that is established in epoxy resin processing but not yet verified for elastomer applications.
© IKVThe aim of the AiF project is therefore to investigate the dielectric analysis with regard to its ability to record the cross-linking process during elastomer injection moulding. To this end, the influence of temperature and pressure on the dielectric properties is being investigated in particular. Natural rubber and EPDM compounds as well as a silicone rubber are examined in order to represent a broad spectrum of materials. With an offline measurement test rig, different process conditions can be simulated in a targeted manner in order to be able to evaluate the penetration depth in addition to the aforementioned temperature and pressure dependency of the measurement signals. The results are then transferred to an in-mould sensor concept. Through process engineering investigations, it is necessary to clarify which positioning in the cavity appears to be sensible, how high the load capacity of the sensor is with regard to the shear and pressure loads that occur and whether general design guidelines can be derived.
If the DEA proves to be suitable, components can be demoulded on the basis of the DEA signal with a defined degree of cross-linking to ensure a consistently high component quality. By avoiding heating times that are too short or too long, material waste and energy can be saved, which enables cost savings in the production of moulded rubber parts.
Project Data and Funding
We would like to thank the AiF for funding the IGF research project (funding code 22803 N) and the project partnersfor their cooperation.
Project duration: 01.07.2023 – 30.06.2025
Project Partners
