Foundry processes in metal mold and The pressure foundry
High Pressure Die Casting is the process of injecting the liquid metal at high speed (50 m / s) and applying a very high pressure (80 to 100 MPa) during solidification. This process is mainly used to make secondary aluminum parts (AlSi9Cu3, AlSi12, AlSi10Mg ...), magnesium alloys (AZ91) or (more rarely) lead alloys. Two types of molding sites are used: cold room presses (aluminum, magnesium, brass, lead) and so-called hot chamber presses (zamak, magnesium). The pressure foundry has many advantages: high productivity (short cycle time, high automation), parts with high dimensional accuracy (near-net-shape) and low thickness. This is the most economical foundry process for large series. This process has for major outlet the automotive market for aluminum (engine blocks, oil pan) and magnesium (steering wheel) but is more diversified in the customer markets for other alloys. Aluminum Die Casting Supplier is good way to get high quality died product at reasonable rates. Shell molding Historically older than die casting, Aluminum Die Casting by Aluminum Die Casting Manufacturer involves gravity filling of a steel mold (single or multi-cavity). This process can be practiced on a static site or a carousel (large automobile series) with 5 to 6 identical tools. Shell molding is used to cast primary aluminum alloys with low iron content (AlSi7Mg0.2, AlSi13 ...), but also copper, various alloys (tin, lead, magnesium). The good quality of the parts (low amount of porosity included) makes it possible to carry out thermal treatments and thus to increase the mechanical characteristics (Rm, Rp0.2, elongation). Shell molding, the second foundry process in metal molds (after die casting) It is used in the automotive sector (parts requiring or requiring cores) but is also used for stressed mechanical parts (mechanical, hydraulic, etc.). Compared to the pressure foundry, the cost of the tools is more limited, which makes it possible economically to produce smaller series (a few hundred pieces). Centrifugation Centrifugation consists in rotating a hollow shell (usually cylindrical) and pouring in the liquid metal, which, via the centrifugal force, then be pressed against the walls of the mold where it will solidify. The inside of the shell can be left unprotected ("LAVAUD" process) or covered by a thin layer of refractory silica (WET SPRAY process). If the process is not very widespread, the tonnage produced is considerable because it is the process used for the production of large cast iron pipes for the supply of water.
In addition to this very important market in tonnage, other alloys can be transformed by centrifugation (steel, cuprous ...).
The axis of centrifugation can be horizontal (the most common) or vertical (less common). The quality of the parts is very good because the centrifugation makes it possible to compress the metal naturally. In addition, this process makes it possible to produce CMMs (Metal Matrix Composites) if the heavier particles are pressed towards the walls of the mold. The main limitation of centrifugal molding is related to its low latitude to make parts apart from simple forms of revolution.
