Selective Laser Sintering (SLS) is a powder based Rapid Prototyping method. The process uses a layer system of building up a part with each layer of powder being sintered separately by a laser. As each layer is sintered it slowly constructs the part step by step. There are various grades of materials used each with there own characteristics but each are used the same way within the SLS machine. The SLS machine basically consists of 3 Powder beds and a Laser. Two of the powder beds hold the feed powder and the third bed holds the part. The part bed is middle of the beds with the laser acting directly perpendicular to this bed. A roller is used to push the layers of powder over the part bed and all three beds have their own heater source. The process itself is a very simple repeatable one. The building of the parts is a repeatable two step process.

Step 1

A roller is positioned beside one of the feed beds. This feed bed then raises a set amount (Usually < 0.1mm) and the roller pushes the raised powder across, covering the part bed with a Powder Layer.

Step 2

With the layer of powder present the laser starts to etch out the desired shape of the part in the powder in effect melting the powder. Once this is done the part bed drops down the set amount and the process continues from the opposite side with the other feed bed raising and the roller distributing another layer of powder over the part bed and the laser etches out the shape. The part is built up in slices with each layer of powder representing a single slice of the part. As the laser melts/sinters the powder each layer fuses together to give a full solid part. Because of the fact that the part is made up in slices very complex shapes and designed can be manufactured that would otherwise be impossible by conventional means.

Selective Laser Sintering (SLS) is a process by which Laser Sintering.com manufactures 3D prototypes. SLS machines fuse or sinter thin layers of powdered thermoplastic materials or metals using a laser beam to create three dimensional functional prototypes. The SLS process has the widest selection of material properties of any Rapid Prototyping process. Sintered parts will be exceptionally durable, and they'll also maintain their material properties long after they're built. Producing a pre-production durable SLS of a part can significantly enhance the geometric visualization of a product, as well as communication among project team members. This physical model can be use for photo-optic stress analysis as well as dynamic vibrational analysis, which further extends engineering design capabilities.

Direct Metal Laser Sintering, also known as Selective Laser Melting, is a relatively new metal powder-based, additive manufacturing process. Like SLS & SLA, the process builds in layers; however the build layer thickness in DMLS is built at either 20 or 40 microns. Also, unlike SLS, support structure is required to build DMLS parts since the weight of the parts in its sintered state is heavy. An absence of support structure in the appropriate areas will cause parts to severely warp.

In the process, a 200 Watt Yb laser traces (essentially welds) the geometry in the X and Y axes from the data in an .stl file. The build tray platform then descends vertically, allowing the Z axis to be built. Before any of the part geometry is sintered, support structure is built to the tray and then the bottom of the part before building the part from the bottom up. Once a layer is completely built, a roller then evenly adds a new 20-micron thin layer of powder over the top of the previously cured part. The process is then repeated until the part is complete.

The build tray is 9.85” x 9.85” x 8”, however parts taller than roughly seven inches may require the machine to be paused while new material is added. This may result in a faint-looking notch in the part. New materials are currently being beta tested, including aluminum and Inconel 625 and 718. With the exception of Ti4 and aluminum, parts can are built in a nitrogen-based environment. All others must be built in an argon-based environment .

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Selective Laser Sintering Investment Castings is a dual process by which Laser Sintering.com generates finely detailed and accurate 3D prototypes. The SLS Investment casting machines fuse or sinter thin layers of traditional waxes or other material using a laser beam to create three dimensional prototypes. The wax assembly is now dipped multiple times in a ceramic slurry, and the desired metal is poured into the hot ceramic shell. The parts are individually removed after the shell is removed and the mold cools. The SLS/IC process has a wide selection of materials including Aluminum 319, 356 & 380; Bronze 421; Magnesium and ZA-12 (Zinc).

Investment Castings are common in the fields of electronics, avionics, aerospace, automotive, pump and valve applications and military command equipment. Sintercasted parts are a wise investment because they are exceptionally durable, and they'll also maintain their material properties long after they're built. Producing a pre-production durable casting of a part can significantly enhance the geometric visualization of a product, as well as communication among project team members. This physical model can be use for photo-optic stress analysis as well as dynamic vibrational analysis, which further extends engineering design capabilities.