System and method of making a crankshaft with alternate materials

A system for manufacturing a crankshaft having alternate materials, the system comprising:

• a molding unit arranged to form a negative sand cast mold of the crankshaft, the mold comprising at least one molded cavity having a pattern with dimensions of the crankshaft, the crankshaft comprising:
• at least four main journals aligned on a crankshaft axis of rotation defining a centerline;
• and
• at least three pin journals, each pin journal being disposed about a respective pin journal axis and positioned between the main journals, each of the respective pin journal axes being oriented parallel to and spaced radially from the crankshaft axis, each of the pin journals being joined to a pair of crank arms for force transmission between the pin journal and the pair of crank arms, each pair of crank arms being joined to a respective main journal for transmitting torque between the pair of crank arms and the respective main journal, each of the main journals, pin journals, and crank arms being arranged to be of a first metallic material,
• at least one of the crank arms arranged to have an over-molded counterweight, the over-molded counterweight being arranged to be over-molded by the at least one of the crank arms and metallurgically bonded thereto, each over-molded counterweight arranged to be disposed opposite a respective pin journal relative to the centerline for balance and stability, each over-molded counterweight arranged to be of a second metallic material, the second metallic material being arranged more dense than the first metallic material for mass efficiency,
• wherein the at least one over-molded counterweight is disposed in the at least one molded cavity;
• a furnace for melting the first metallic material at between 1400 degrees Celsius (° C.) and 1600° C. to define a molten metallic material;
• a pouring mechanism for pouring the molten metallic material in the negative sand cast mold at between 1350° C. and 1450° C. such that the at least one over-molded counterweight is over-molded by the molten metallic material;
• a cooling area for solidifying the molten metallic material in the negative sand cast mold such that the at least one of the crank arms is formed to over-mold the at least one over-molded counterweight, the at least one over-molded counterweight being metallurgically bonded to the at least one of the crank arms defining the crankshaft;
• a separation unit for separating the crankshaft from the negative sand cast mold, the crankshaft having a weight ratio of the second metallic material to the first metallic material of between 0.20 to 0.50;
• a controller in communication with the molding unit, the furnace, the pouring mechanism, and the separation unit, the controller configured to control the molding unit, the furnace, the pouring mechanism, and the separation unit;
• and
• a power source configured to power the molding unit, the furnace, the pouring mechanism, the separation unit, and the controller.

A method of manufacturing a crankshaft having alternate materials, the method comprising:

• providing a negative sand cast mold of the crankshaft, the crankshaft comprising:
• at least four main journals aligned on a crankshaft axis of rotation defining a centerline;
• and
• at least three pin journals, each pin journal being disposed about a respective pin journal axis and positioned between the main journals, each of the respective pin journal axes being oriented parallel to and spaced radially from the crankshaft axis, each of the pin journals being joined to a pair of crank arms for force transmission between the pin journal and the pair of crank arms, each pair of crank arms being joined to a respective main journal for transmitting torque between the pair of crank arms and the respective main journal, each of the main journals, pin journals, and crank arms being arranged to be of a first metallic material;
• at least one of the crank arms arranged to have an over-molded counterweight, the over-molded counterweight being arranged to be over-molded by the at least one of the crank arms and metallurgically bonded thereto, each over-molded counterweight arranged to be disposed opposite a respective pin journal relative to the centerline for balance and stability, each over-molded counterweight arranged to be of a second metallic material, the second metallic material being arranged more dense than the first metallic material for mass efficiency;
• disposing the at least one over-molded counterweight in the negative mold of the crankshaft;
• melting the first metallic material at between 1400 degrees Celsius (° C.) and 1600° C. to define a molten metallic material;
• pouring the molten metallic material in the negative sand cast mold at between 1350° C. and 1450° C. such that the at least one over-molded counterweight is over-molded by the molten metallic material;
• solidifying the molten metallic material in the negative sand cast mold such that the at least one of the crank arms is formed to over-mold the at least one over-molded counterweight, the at least one over-molded counterweight being metallurgically bonded to the at least one of the crank arms defining the crankshaft;
• and
• separating the crankshaft from the negative sand cast mold, the crankshaft having a weight ratio of the second metallic material to the first metallic material of between 0.20 to 0.50.