4. Conclusions
A rheological characterization of hard metal mixtures, using experimental
equipment, produces viscosity values according to the shear rate
necessary to design an extrusion die for carbide rods with inner helical
holes. Furthermore, FE simulations are carried out by using LS-DYNA
code, in order to predict the evolution of the material in the extrusion
process. To correctly-simulate of the process, it is important to choose
properly the various parameters, especially geometric ones, and to
enter the data related to the rheological characterization of the mixtures.
The simulations show the correct design of the extrusion die, because
it reaches the appointed purpose: to assign a proper twist to the
paste in the extrusion process. Additional FEM analyses are performed
in order to validate the correct rheological parameters used in FE
model. This operation is fundamental in order to realize the helical
holes in the extruded product. In the final phase of the study, the die
is manufactured and extrusion tests are conducted. These tests confirm
the result predicted from FEM analysis.