Analysing Powder Injection Moulding of a Helix Geometry Using Soft Tooling

Freeform injection moulding is a novel technology for powder injection moulding where a sacrificial 3D printed mould (i.e., a soft tooling) is used as an insert in the injection process. The use of 3D printed moulds enable a higher geometrical design flexibility as compared to the conventional injection moulding process. However, there is still very limited knowledge on how the sacrificial soft tooling material and powder suspension handles the increased geometrical complexity during the process. In this study, a stainless steel powder suspension is injected into a geometrically challenging sacrificial mould (viz. a helix structure) that is produced by vat photopolymerization additive manufacturing. Computed tomography is used to quantify the geometrical precision of the mould both before and after injection. In addition, a new numerical model that considers the suspension feedstock is developed to investigate the powder injection moulding process. The numerical results are found to be in qualitative good agreement with the experimental findings in terms of pinpointing critical areas of the structure, thereby highlighting a new pathway for evaluating sacrificial inserts for powder injection moulding with a high geometrical complexity.

Enabling Micro Injection Moulding Using a Soft Tooling Process Chain with Inserts Made of Mortar Material

The manufacturing of inserts for micro injection moulding made of mortar material is presented in this work. The fabrication of the mortar insert described in this publication relied on a versatile and relatively fast rapid prototyping process based on soft tooling. The mortar insert has a QR code with micro features on its surface, which was replicated in acrylonitrile butadiene styrene (ABS) polymer by the micro injection moulding process. With this approach, it is possible to fabricate hard inserts for micro injection moulding purposes that are able to compete with conventional-made inserts made of tool steel.

High cadmium and nickel contents in sunflower kernels

High cadmium and nickel contents in sunflower kernels intended for human consumption are reported. The cadmium contents of 55 samples from North America and Europe were 0.25-0.69 mg/kg with averages from different countries of 0.32-0.54 mg/kg. The contents in kernels from bird seeds (i.e. animal feed) from China and Egypt were much lower. The cadmium content of sunflower kernels for human consumption might pose a risk to human health. Danish authorities recommend the Danish consumers do not eat large amounts of sunflower kernels for a long period of time. The nickel contents of 25 of the samples of kernels for human consumption were 2.3-5.3 mg/kg. This is comparable with that found in different kinds of nuts with high nickel contents.