*2.2.2 SLS RapidSteel*

Just as a cavity can be produced directly by stereolithography, the laser sintering method can also be used to construct tool cavities directly. Digital core and cavity geometry models are developed and sent to a Sinterstation manufacturing device in RapidSteel powder with DTM's RapidSteel (also known as RapidTool, earlier similar methods are known as Indirect Metal Selective Laser Sintering). This material comprises of mild stainless-steel particles that are covered with a thin layer of a material for a polymer binder. The Sinterstation generates green components that fire in a furnace afterwards. The furnace removes the polymer binder and by capillary action infiltrates bronze into the inserts of the mold. This method generates a completely thick tool consisting of approximately 60% steel and 40% bronze. Then the inserts are completed, drilled for ejector pins, and fitted to the base of the mold.

The technique generates a durable mold that can be used as well as die-casting apps for injection mold tooling. Hundreds of aluminum, zinc, and magnesium components were casted using RapidSteel molds. The technique enables complicated geometries, and molds from RapidSteel can resist injection molding circumstances. RapidSteel, however, needs finishing and polishing that can take time scheme of the SLS process can be seen in **Figure 3** [6].

#### *2.2.3 Copper polyamide tooling*

The DTM (Austin, Texas) copper polyamide tooling method is consisted of selective laser sintering of a matrix of copper and polyamide powder to manufacture

#### **Figure 3.** *DTM SLS Sinterstation 2500 plus [8].*

a tool. All sintering process happens among the polyamide powder particles. This technique provides improvements in toughness of items unlike some of the other smooth tooling techniques and heat transfer. The copper is not only appropriate for these properties but also can offer some advantages to users like operating a device with pressure and temperature settings which are closer to the environment of the process. The main inconvenience of it is the material's low resistance [7].
