Checking out the metal parts casting processes, there are several different types of techniques that may be used. Two particular ones are sand casting vs. centrifugal casting. Each process has its strengths based on the types of parts they are most suitable for, as picking the right process ensures the part will work for your application.

Centrifugal Casting

Centrifugal casting processes consist of a cylindrically shaped die. This die rotates on either a vertical or horizontal axis. Molten metal is poured into the preheated spinning die and distributed in the mold under controlled pressure to produce a casting with superior internal soundness. The horizontal centrifugal casting process has a die rotating about the horizontal axis, typically producing tubular parts with a length significantly longer than its outside diameter. The vertical centrifugal casting process involves a die rotating about the vertical axis, which generally produces ring-type and cylinder-type parts with the height of the casting less than twice the width.

Sand Casting

The sand casting process involves the use of a sand mold. Molten metal is poured into the mold and allowed to harden into the desired shape. Cores may be placed into the mold to create internal structures and walls. These cores are taken out after the sand mold is broken apart, as the sand cores are shaken out.

Sand casting may be used to produce a variety of simple and complex shapes, including those that may not be achieved through the use of other casting processes. The process also may be used to produce parts in various sizes, with the technique especially helpful for larger parts. The surface of the part undergoes machining to make the desired finishing and to reach dimensional specifications.

Sand Casting vs. Centrifugal Casting

When comparing these two processes for a project, keep in mind the part’s specifications. Sand casting is more suitable when a customer needs intricate parts in various shapes as well as parts with complex internal structures. Centrifugal casting is limited in its ability to produce special shapes and certain lengths compared to sand and other casting methods. Centrifugal casting techniques are typically reserved for symmetrical parts such as tubes and cylinders with limited I.D. features as shrinkage and impurities tend to occur around the I.D. area and need to be removed by machining post casting.

The sand casting process involves multiple steps and a longer solidification time after pouring; as a result, the casting may contain unwanted impurities. If the purities may impact the use of the part for specific applications, centrifugal techniques may be adequate.

When casting the part, the molten metal tends to shrink when cooling. Sand casting techniques take this into account by making a slightly larger mold than the part’s size and incorporating a gating system to optimize molding filling. However, shrinkage cannot be eliminated entirely for sand casting. The same shrinking process also occurs with centrifugal casting. However, centrifugal casting does not experience centerline shrink.

If you need parts manufacturing processes and desire sand casting techniques, reach out to Impro for more information.