There are many types of rapid manufacturing services on markets, for example, SLS, SLM, and DMLS. They all refer to 3D printing technology, but they are slightly different. They primarily differ in materials. The materials used for SLS printing are plastic, glass, ceramic, while SLM or DMLS as the most popular metal 3D printing technologies use metal powder. Besides the difference in materials used, their processes though are very similar still have some differences. SLS vs. Metal Printing Technology: let us see what they are in common and what they differ from each other.
SLS vs. Metal Printing Technology: Their Similarities
SLS and metal printing technologies like SLM, DMLS are, in essence, the same thing with an extremely similar process.
Here is the process: firstly, a thin layer of powder is deposited by a laser sintering 3D printer on the build platform. A feeder chamber that is located either above the build platform or on the side distributes the power and an automatic scraper and roller are used to smooth the layer. Then, a laser beams into the powder, printing the shape of the printed object on the first layer and solidifying the printed layer. The build platform moves down and the printer repeats the process layer by layer. A powerful bond is created between each layer. The major difference between the processes of SLS & metal printing is in their solidify methods.
SLS vs. Metal Printing Technology: Their Differences
In SLS（Selective Laser Sintering）process, the method to solidify the powder is by using a focused laser beam. With this method, at the molecular level, the powder is sintered together instead of melt. Using this method, at the molecular level, the powder is sintered together instead of melt together. This means the final 3D printed objects are more or less porous. The good part of this solidifying method is that it is easier to print alloys that contain materials with varying melting points. And you can also print from a mixture of plastic and metal materials. For example, using the mixture of aluminum powder and nylon powder, which is called Alumide, you can get printed parts of high stiffness and good thermal performance.
Common 3D printable materials for the SLS process offered by most rapid manufacturing services providers are as followed: Nylon, Glass-filled polyamide, Alumide, Carbon-filled polyamide, etc.
As for the metal printing process, it also uses the focused laser beam to solidify the powder. But the power is melted together. The result is a more homogeneous printed part. This makes it possible to melt the pure metal because it has only one melting point, not the variety you would find in an alloy.
Ideal printable materials for metal printing process are pure metal materials such as titanium, alloys including stainless steel, copper alloys, nickel-based alloys, titanium alloys, aluminum, and precious metals like silver, gold, platinum.
In addition, generally speaking, printing parts from plastic materials do not require any sort of support structure. However, using metal 3D printing, the support structure is required as the power is melt. You need support structures to make sure the part does not move when printing and to conduct excessive heat away from critical places.
Which to go for between these two types of rapid manufacturing services? In a nutshell, if you want printed parts made from an alloy of some sort, you can go for SLS and one of metal printing technologies - DMLS. And if you want parts printed from pure metal, SLS is not suitable any longer. In this case, you might opt for another metal printing process - SLM. (>>>> Metal 3D printing is on its rapid rise)
When to Use SLS & Metal Printing
In additive manufacturing, printed parts are built up layer by layer instead of cutting and removing materials. Thus, SLS, SLM, DMLS, and other 3D printing technologies are most used for creating products with complex geometries and internal details, such as nested cores and spiral vents, or printing objects from precious metals which can be rather expensive to machine using traditional manufacturing processes. What’s more, 3D printing technologies might also be a more effective and economical option for producing a small number of parts or option for projects with a tight deadline.
However, if you are looking for producing a medium or large quantity of parts, 3D printing methods whether SLS or metal printing can be more expensive than traditional manufacturing processes such as CNC machining. And compared to printed parts, CNC machined parts have finer detail and smoother surface finish. Thus, if this is your case - large quantity production and superior surface finish, other manufacturing methods like CNC machining might be more suitable for your project, technically and economically.
If you have a product want to manufacture or an idea want to prototype, no matter you are working with metal or plastic, partnering with an experienced and professional rapid manufacturing services provider like Tuowei, you can get access to the best manufacturing technologies including SLS, metal printing technologies, CNC machining, and injection molding for your needs.