Analysis of function oriented surfaces of electrical discharge machined moulds
For thin-walled injection moulded parts with high aspect ratios, the achievable flow path length and, consequently, the required injection pressure are critical factors. Studies at IKV have shown that, compared to milled and polished mould surfaces, eroded mould surfaces can achieve a longer flow path. This is attributed to the incomplete moulding of the eroded, crater-shaped mould surface, which creates micro air pockets between the melt and the mould surface. The air pockets have an insulating effect at the interface and inhibit heat transfer from the melt to the mould. The influence of eroded mould surfaces on the flow behaviour of thermoplastics will therefore be further analysed in the project „Analysis of function-oriented surfaces of injection moulding cavities manufactured by electrical discharge machining“ (AOS).
The aim is to predict and thoroughly describe how the surface replication and thus the heat transfer depend on the material, the flow path and local melting properties such as pressure and temperature. These results can then be used in simulations to improve our understanding of the flow behaviour of plastics in structured injection moulds. First, the existing model for the surface replication is to be further developed. This involves transferring the results obtained so far for semi-crystalline thermoplastics to amorphous moulding compounds. Furthermore, the moulded part thickness will be varied within the range of values commonly found in the packaging industry, since wall thickness significantly determines the achievable flow path. In addition, the influence of active venting and variothermal temperature control on surface replication will be investigated. Results from these investigations will then be used to develop a simulation model.
© IKVProject data and funding
We would like to thank the DFG for funding the project (funding code HO 4776/63-2) within the and the project partners for their cooperation.
Project start: 01.08.2025
