- Field-assisted sintering technology (FAST), also well-known under the term spark-plasma sintering (SPS), is a grown process technology to produce parts made of a powder material. The process itself has the advantage of carrying out compaction, sintering and cooling with high temperature rates in one process step. This is done using an electrical current, which heats the graphite tools and, accordingly, the powder within the die itself. The theoretical description itself is very complicated caused by the fact of having electro-thermomechanical coupling effects, large deformations, contact problems for each field, but the essential point are the amount of experiments required to determine the parameters of the model. In this article, the required experiments to obtain the electrical, thermal and mechanical properties of both materials are discussed, a constitutive model of compressible thermo-viscoplasticity for copper powder is proposed, and aspects of material parameter identification are addressed.