Characterisation and replication of metallic micro-fluidic devices using three different powders processed by hot embossing

Abstract

Abstract This study presents the results of micro-replication of different powder feedstocks samples. The feedstocks of metal powder and plastic binder with various solid loading in the range from 40% to 75% were prepared. The different feedstock comprises 316 L stainless steel, Fe Ni 8%, or WC-Co and a multi-component binder system. Suitable polymers/powder formulations for the hot embossing were chosen and characterised by thermogravimetric analyses (TGA), mixer measurements and capillary rheology testing in order to check and quantify the viscosity and homogeneity of all the developed feedstocks. The photoresist (SU-8) was used as a structural material that was deposited onto the Si wafer to obtain the micro-fluidic systems with low roughness. Then the elastomeric mould was obtained using casting with one face that contains all the details of the original master, very well defined and smooth sidewalls. The objective of the paper is to develop metallic micro-structured die mould cavities with higher quality using hot embossing process with various different powder loaded polymers. However, a rapid prototyping process was adapted for fast and cost-efficient manufacturing. This study compares the capacities of three different metallic powders to emboss of the metallic replications by hot embossing, the dimensional stability, the mechanical strength and particularly hardness of sintered components. The results show that the feedstock can be used for the manufacturing of the micro-fluidic die mould cavities with a low roughness, proper dimensions and good shape retention.