Benefits of Gravity Die Casting

Gravity die casting is basically used to fabricate metal alloys with dense, high-quality mechanical attributes. At times it is also referred to as permanent mold casting. This process includes pouring molten metal into molds with the help of a ladle and it even relies on gravity alone to fill them. The gravity method led to various benefits which include faster production times, smoother surfaces, and exceptional dimensional accuracy.

In this particular process, the molten metal is poured directly into a semi-permanent or permanent die with the help of a ladle which then can be fully automated.

Compared to other processes gravity die casting process also tends to be more cost-effective. It is because it does not need any large or complex machinery to inject the metal into the molds. Along with that, the molds themselves are reused indefinitely. It then reuses the wasted time and resources which are required to constantly produce new dies. This method then produces high-volume, quality casts that need very little finishing.

Alternatives to Gravity Die Casting

Rather than gravity dies casting aluminum die casting is often used for larger production orders. The use of sand casting is in creating three-dimensional hollows and complex molds. It usually has higher tooling costs.

Materials & Process of Gravity Die Casting

This method typically works best with non-ferrous alloys like aluminum and copper. It is performed manually but in certain circumstances, it can also be automated. This is a simple process: at first, the mold undergoes heat treatment, and then the coating is given with a lubricating die release, which then is easily removed after it has cooled. Then, into the cavity, the liquid metal is poured and allowed to flow.

Automotive Industry & Gravity Die Casting

Gravity die casting manufacturers invest in well-designed, significantly tooled permanent molds, which results in valuable consistency. Due to the long-term reusability of the molds surface details are reliably reproduced. It is formed using durable materials like stainless steel, grey cast iron, and graphite. Although for simply shaped, single-part molds gravity casting works best. It even produces more complex casts effectively. 

Attributes of Permanent Mold Casting

Permanent mold casting aluminum is similar to the process of sand casting and in this method to the pouring of molten metal is done in a metallic mold without external pressure. Molds are prepared from cast iron or steel which after every casting are not destroyed or rebuilt. The process is called Permanent mold casting as these molds last for long periods.

Usually, they are made of non-ferrous alloys, grey cast iron (having high resistance to thermal shocks), or alloy steels (for very high temperatures and withstanding surface erosion. With a refractory, the inner surfaces of the mold are coated first and then with lamp black or core oil. This is performed to reduce the chilling effect on the cast metal and to facilitate the removal of casting, and prevent the adherence of the molten metal to the mold.

In this permanent mold aluminum casting process, there is no application of external pressure but for the casting of metal in the mold hydrostatic pressure created by the risers is mainly responsible. This process is sometimes called gravity die casting as no external pressure is applied.

For hollow castings, the molds provide facilities for setting cores and ejector pins for ejecting out casting from the mold. In two halves the molds are generally made which are then hinged at one end and the other end has provision for clamping.

Because of fast conduction through the metallic mold, the heat of the molten metal is removed very rapidly. The metal shrinks very fast and then leaves an air space between the mold surface and casting.

On a sliding carriage, the two halves of the mold may be mounted where on one side one half is fixed and the other half is movable along a horizontal bed.

For hollow casting and depending upon the shape of the hollow portion required either metal cores or dry sand cores can be used. The dry sand core is used for complicated shapes having varying diameters by the permanent mold casting aluminum manufacturer. If the metallic cores are used, before the metal starts solidifying, they have to be withdrawn.