ABSTRACT

To reduce the lead time and costs for developing short run production injection moulding tools the potential of additive manufactured mould inserts is investigated. These hybrid moulds are compared to conventional steel-based moulds, considering mechanical and thermal differences. For part production and insert material, respectively polypropylene and polyamide12 manufactured by Multi Jet Fusion (MJF) are chosen. Moldex3D simulation results show that lower clamping forces and injection pressures are sufficient upon using MJF inserts due to a 20 times lower thermal diffusivity compared to conventional steel, resulting in thinner skin layers and increased solidification times. Practical injection moulding parameters have been optimized by reducing the cooling time with 75 seconds (60%) using forced convectional cooling at 15 °C. Core and cavity inserts show a deviating cooling behaviour linked to the higher amount of insert material and presence of steel. The wear of the mould inserts is minor after producing 360 parts. .

摘要

为了减少开发短期生产的注模工具的交货时间和成本，研究了增材制造的模具嵌件的潜力。考虑到机械和热学差异，将这些混合模具与常规钢基模具进行了比较。对于零件生产和插入材料，分别选择了Multi Jet Fusion（MJF）生产的聚丙烯和聚酰胺12。Moldex3D仿真结果表明，使用MJF刀片时，较低的夹紧力和注射压力就足够了，这是因为其热扩散率是传统钢的20倍，从而导致了更薄的表皮层和更长的凝固时间。通过在15°C下进行强制对流冷却，将冷却时间缩短了75秒（60％），从而优化了实用的注塑参数。型芯和型腔镶件显示出不同的冷却性能，这与较高数量的镶件材料和钢的存在有关。在生产360个零件之后，模具插件的磨损很小。。