Tilt Pouring

Tilt pouring, also known as tilt casting, is one variation of the gravity die-casting. Tilt pouring is a process with the unique feature of transferring the liquid metal into a mould by simple mechanical means under the action of gravity, yet without surface turbulence. The goal is to reduce porosity and inclusions by limiting turbulence. It therefore has the potential to produce very high quality castings.

In tilt pour casting process, the molten metal is poured into a mould by tilting the mould. This tilting of the machine is performed at the controlled speed so the metal enters the mould cavity at the controlled speed and with the minimum air intake that results in the inner casting purity. Figure 2 illustrates the tilt pouring casting process. In this process, once the metal is poured into the pouring cups, the mold is slowly rotated to the vertical position. Under gravity, the metal slowly fills the mold cavity at a constant rate. The most critical part of metal transfer is when the tilt angle is close to the vertical one, where the rate of rotation must be minimum. Solidification starts as soon as the metal enters the mould.




In traditional tilt-pouring the mould parting line is perpendicular to the floor during the solidification phase, while in reverse tilting the parting line is parallel to the floor. Turning the parting fine allows the casting to be center-fed similar to the way a casting is produced in the low-pressure process. This feature makes reverse tilting a cost-effective alternative to capital-intensive low pressure casting.

The reverse-tilting process is ideally suited for radial type castings, such as wheels, hubs, compressor housings, automotive structural castings, and cookware, but the process is not limited to radial casting and has been used to cast high-performance brake calipers.

Applications:

1. This process is used for casting materials with a high propensity to oxidation and foaming, such as aluminum gravity die casting, and aluminum-bearing copper alloys, in particular brass gravity die casting.

2. Industrial applications that benefit from tilt pour permanent, mold casting include: air cylinders, base castings, cold plates, couplings, compressor bodies, differential housings, gear box housings, pistons, suspension components, valve bodies, hydraulic cylinders etc.

Advantages:

1. Homogeneous casting structure is possible.

2. Repeatability of process parameters is possible.

3. It can produce castings with improved surface finish.

4. Tighter tolerances are achieved than conventional sand castings.

5. Metal yield is better as the wastage of metal is minimal.

6. Pouring parameters are more stable.

7. It has low mould costs comparing to the high pressure casting moulds.

8. High automation level is possible.

Disadvantages:

1. Size of the part produced is limited to usually less than 10 kg.

2. It is not possible to produce complex shaped parts.