3D printing, also known as additive manufacturing, is a newer technology to create molds without using a pattern. A commonly used technology in this field is called binder jetting 3D printing that can directly create sand molds. This technology jets binder into the powder bed of sand to create 3D printed foundry molds.
During this jetting process, a binder is printed onto the bed of foundry sand using inkjet printing head. This forms one thin layer of the part. After printing this layer, the foundry sand powder bed is lowered and another thin layer of the powder is spread over the already printed layer. Then the printing heads print another layer by using the same method. This layer by layer printing leads to complex 3D printed foundry molds.
3D printed foundry molds provide a mean to offer a flexible method for traditionally designed casting. However, a more pronounced benefit of this technology is the ability to create complex geometries that cannot be created through traditional casting methods. Furthermore, this process of printing layer by layer gives the designer a flexibility to integrate sprues, vents, and runners directly into the 3D printed mold design. Moreover, when the final part is created, large metal geometries can be created through the binder jetting and casting process chain. This way, even multiple molds can be printed and fitted together afterward to pour large metal castings.
Any casting foundry considering 3D printing of molds should also consider the effect of material used to print these 3D molds. Although experts at most foundries know the effects of traditional materials like silica sand, synthetics, and natural minerals in the molds, they might not know the effects of the material used in the 3D printing of molds.
There are some studies available to view the effects of different materials used in the 3D printing of the molds, but one must rely on experience to know the exact effects.