Selective heat sintering (SHS) and selective laser melting (SLM) are two common types of 3D printing used in the manufacturing industry. While not as popular as fused deposition modeling (FDM), they offer many advantages for commercial applications. With SHS and SLM, the raw material isn’t deposited. Rather, the raw material is “selectively” joined via heat. What’s the difference between SHS and SLM exactly?
What Is Selective Heat Sintering?
SHS is a 3D printing process developed by a team of doctors at the University of Texas (UT) in the 1980s. It involves the use of a specialized 3D printer with a thermal head that projects heat onto a bed of raw material, such as powdered thermoplastic. As the thermal head moves over the bed, it beams heat down onto the raw material. Exposure to this heat causes the raw material to bind together.
SHS is distinguished from traditional 3D printing processes, including FDM, by the way in which it builds objects. traditional 3D printing processes build objects by depositing raw material onto a bed. SHS, on the other hand, builds objects by heating up raw material that’s already present in the bed. The print bed is filled with powder particles, after which a thermal print head moves over to selectively heat up certain areas. Only the powder particles exposed to the print head’s heat will bind together.
What Is Selective Laser Melting?
SLM is a 3D printing process developed by German researchers in the mid-1990s. Like SHS, it involves the use of a specialized 3D printer to heat up raw material. With that said, SLM 3D printers are more powerful than their SHS counterparts. They apply more heat so that the raw material doesn’t just stick together; it fuses together.
The print heads used in SHS and SLM also differ. SHS uses a thermal heat that’s designed specifically to project heat, whereas SLM uses a laser print heat that’s designed specifically to project laser light. The laser light is still hot. In fact, it’s hotter than a thermal print head. Once exposed to this laser, the raw material fuses together.
Because it uses a laser print head, as opposed to simply a thermal print head, SLM 3D printers typically cost more than SHS 3D printers. However, SLM 3D printers are better suited at creating strong and durable objects with accurate dimensions. The laser print head doesn’t just bind the raw material together; it fuses them together under extreme pressure.