Vforge’s proprietary knowledge is based on integrating the combination of horizontal cold chamber diecasting machines with a customized horizontal continuous casting system designed to produce the thixotropic microstructure needed to practice semi-solid thixocasting. This combined approach significantly reduces operating costs, allows for onsite recycling, and facilitates the development of specialty alloy combinations targeted for specific applications. Raw material is certified for chemistry, microstructure, gas content, and suitability for semi-solid thixocasting.
Vforge has been using horizontal cold chamber diecasting machines for semi-solid thixocasting aluminum alloys since 1999. This picture shows one of Vforge’s semi-solid thixocasting machines. It comprises an approximately 400 US ton clamp casting system coupled with a carousel 8-station heating system. This system is currently used to produce parts weighing from less than one ounce in multi-cavity tooling to a maximum of approximately 2 lbs.
Initially employing raw material supplied by several suppliers, in the late 2000’s, Vforge acquired an electric melting furnace and coupled it to a horizontal casting machine capable of simultaneously casting up to three strands of bar at diameters from 2” to 5”. This represents an ability to generate shot weights from roughly 0.5 lbs. to almost 20 lbs.
The Vforge electric melting furnace is shown to the left. The furnace is equipped with a spinning nozzle degasser dispensing a fine distribution of nitrogen bubbles to entrap and expel gases and a porous ceramic filter through which the alloy flows just prior to entering the casting mold. Filtered and degassed liquid aluminum alloy flows under gravity from what is conventionally referred to as the dip-well of the furnace through a horizontal trough into a casting tundish. Underpouring in this manner maintains metal quality as the aluminum flows quiescently under the surface which is undisturbed.
From the bottom of the tundish, liquid aluminum then flows through a ceramic connection tube (nozzle) into the casting mold. The Vforge proprietary casting mold design produces the required semi-solid microstructure as it transforms the metal from liquid to solid.
