Direct Metal Laser Sintering (DMLS) from EOS involves the direct processing of metal powders in a laser sintering machine.
Typically, the machine is used for the production of tool inserts, but it also is possible to produce metal components. Two materials are available for the DMLS process: 1) bronze-based materials, which are used for injection molding of up to 1,000 parts in a variety of materials, and 2) steel-based material, which is useful for up to 100,000 plastic injection molded parts.
This process was used to produce injection mold tooling for a Germany appliance manufacturer. Seven mold inserts were produced in 20 hours using the bronze-based material. Several thousands molded parts were produced in 30 percent glass-filled polyamide. The tool took two weeks to produce compared to 10 weeks for a machined tool and cost about $6,800 compared to $8,200 for the machined tool.
DMLS offers good feature definition, although the surface definition of the steel-based powder needs improving. Also, the steel material builds slowly.
Direct metal laser sintering (DMLS), also called selective laser sintering (SLS), is a type of metal additive manufacturing or 3D printing. It’s used for both for rapid prototyping and mass production of metal parts.
The method is very similar to selective laser melting (SLM), also called direct metal laser melting (DMLM), but on a molecular level, the powder is only sintered (not melted) together. This results in parts that are more less porous than the melting method. The advantage to this is that you can easily print from alloys containing materials with different melting points. You can even combine metal and plastic materials. A good example is Alumide, which is a mixture of nylon powder + aluminum powder.
Another difference between sintering and melting in these two processes is the temperature used to fuse the metal powder. SLM heats the metal powder until it fully melts into a liquid. DMLS does not melt the metal powder, so less energy is needed. Sintering heats particles enough so that their surfaces weld together.
The working material for this 3D printing process is finely powdered metal. Typically the manufactured size of the metal particles is 20 – 40 micrometers. The particle size and shape limit the detail resolution of the final part. Smaller metal particle size and less variation allow better resolution.
Other resolution limits in this technology are the layer height and the size of the laser spot. Like other 3D printing processes, the model is divided into many fine layers, which are then printed one-by-one to build the final part. Printable layer heights are approximately the maximum size of the metal powder used.
The DMLS story begins in the 90s with the invention of selective laser sintering (SLS), as described by Carl Deckard‘s now expired patent. In parallel, EOS, a company in Munich, Germany, was also developing additive manufacturing technologies, including laser sintering for plastics and metals.
Advances of the technology continued with associated licensing agreements (and legal battles) until EOS ultimately gained the worldwide rights for SLS. The company then proceeded to champion DMLS (nee SLS) technology, producing the first commercial DMLS printers in 1995. EOS continues to be the leader in DMLS technology today.
Thank for you describe this concept well, But 3D printing is coming