FDM vs SLS 3D Printing

3D printing is an awesome technology that is changing the world in which we live in. This is a form of manufacturing that blows away other types in quite a few aspects; it is just significant! I want to compare and contrast two different styles of 3D printing. I’m going to cover Selective Laser Sintering (SLS) methods, as well as Fused Deposition Manufacturing (FDM). Before I do that, let me cover a “universal” process that all 3D printing processes hold to, as well as the general underlying message in all 3D printing methods.

Before anything can be manufactured through 3D printing, it has to be designed! This means there needs to be an engineer or a 3D designer working on the computer with 3D software developing a blueprint for the machine to use. All forms of 3D printing involve a CAM system, or a computer-aided-manufacturing system. This means that whether it be a jet, laser, or nozzle, all methods of this technology involve a computer telling the material dispenser where to go. This is definitely not done by hand on the fly! When it comes down to any form of additive manufacturing, there is an underlying process that applies to virtually all styles of manufacturing. A product will be manufactured one layer at a time. The material will be fused somehow at each individual layer, not matter how small. These layers could be just a few microns, or it could be a couple millimeters. (a human hair has a diameter of 20 microns) Regardless, 3D printing involves the layer by layer assembly of materials by a computer aided manufacturing method. Let’s compare both.

Fused Deposition Manufacturing (FDM) is a form of 3D printing that is a little bit simpler than other methods. It typically deals with thermoplastics for the most part, as the process involves a very basic melting process. Essentially, a nozzle will be hooked up to a spool of material in string form. This material could consist of polymers, ABS plastic, or whatever. The nozzle itself will be very hot, and as the material is pushed through the nozzle, it will be melted on top of the product. The material will be quick to solidify, but layers of melted materials will be stacked on top of each other to yield a final product. Think of a hot glue gun laying down layers of glue which quickly solidify, and stacking each layer of glue into a final product. The pros of this method are the simplicity. The machines capable of doing this are very simple compared to other printers, and are very inexpensive compared to others. Printers could go for $50,000 to $500,000 pretty easily. Some FDM printers go for less than $1,000. They are cheap! The downside, is that they can only make very small parts. On top of that, the parts are very low resolution. Finally, the process takes much more time than other methods. Finally, FDM methods require support materials when building. It turns into a “you get your money’s worth” kind of situations.

Selective Laser Sintering is a great method of manufacturing that really stands out. As you know from earlier, 3D printing involves the layer by layer stacking of material until a final product is produced. With SLS, each layer involves a layer of material being spread over the entire build envelope, or section where products can be assembled layer-by-layer. At each individual layer, a laser will melt the powder material together into a solid, and then another layer of powder material will be laid down – just to be laser melted again. A laser will melt material together per each layer, until a final product is yielded. The pros of this method would be that virtually anything can be made, as support material isn’t needed. This printer is much quicker than FDM. The parts are usually very high resolution, and high quality. This type of 3D printing is quite a bit more expensive on the downside.