Views: 240 Author: Wendy Publish Time: 2023-04-17 Origin: Site Inquire
The more well-known of the two primary die casting techniques is hot-chamber die casting, sometimes referred to as gooseneck casting or hot casting. The injection mechanism's cylinder chamber is submerged entirely in the molten metal bath throughout this procedure. The molten metal is drawn into the die cavity by a gooseneck metal feed system. In comparison to the cold-chamber procedure, this method is more conducive to greater rates of part manufacturing.
While rapid and simple mold injection is made possible by direct immersion in the molten bath, this practice also increases corrosion susceptibility. Due of this, applications that use metals with low melting points and great fluidity are best suited for the hot-chamber die casting method. Lead, magnesium, zinc, and copper aluminum are suitable metals for the hot-chamber die casting technique.
Hot-chamber die casting and cold-chamber die casting are extremely comparable processes. The molten metal is automatically or manually ladled into the injection system using a design that prioritizes reducing machine corrosion above production efficiency. As a result, the injection mechanism is no longer required to be submerged in a bath of molten metal.
The cold-chamber method can be a great substitute for applications that are too corrosive for the immersion design of hot-chamber die casting. Among these uses is the casting of metals with high melting points, including aluminum and its alloys.
Low pressure die casting: what is it? The greatest candidates for low-pressure die casting are aluminum parts with symmetrical rotational axes. Wheels for vehicles, for instance, are frequently made using low-pressure die casting. In this kind of procedure, a riser tube connects the mold, which is positioned vertically above the molten metal bath. The metal is drawn up and into the mold when the chamber is pressured (often between 20 and 100kPa). High casting yields are achieved by doing away with feeds in this low pressure aluminum casting process.
A relatively recent die casting technique that produces parts with greater strength and less porosity is vacuum pressure casting (VPC). With the exception of the positions of the molten metal bath and the die-cast mold being switched, this procedure is comparable to low-pressure die casting. Vacuum buildup inside the cylinder chamber might push the molten metal into the mold cavity. Turbulence is lessened and the number of gas inclusions is constrained by this design. Applications intended for post-casting heat treatment benefit most from vacuum die casting.
For casting metals and alloys with poor fluidity, squeeze casting was developed as a practical option. Molten metal is poured into an open die during this procedure, which is then squeezed shut, pushing the metal into the recesses of the molding. The squeeze casting method produces incredibly thick products and works in conjunction with later heat processing. The procedure is utilized in applications that require fiber reinforcement and is most frequently connected to molten aluminum.
Semi-solid die casting, sometimes called Thixoforming, is another process that delivers minimal porosity and maximum density. A machine cuts the workpiece into smaller slugs, and then heated. Once the metal has reached the phase transition between solid and liquid, resulting in a somewhat slushy texture, a shot sleeve forces it into the mold cavity, where it hardens. The benefit of this is improved precision. Non-ferrous metals such as magnesium alloy and aluminum alloy are most often used with the semi-solid die casting process.