There’s been a lot of buzz lately about 3D printing metals like steel and bronze – but how does it work? 3D printing with metal has a plethora of applications in industries like jewelry, medical, dental, and manufacturing. Although most of these applications are focused on corporate use cases, there are companies working on making it possible for consumers to 3D print with metal on their desktop printers. Here’s how the technology behind 3D printing metal works:
Top 3 Methods For 3D Printing Metal
1. Metal binder jetting 3D Printing with metal starts out like any other printing process – with an awesome 3D design and a slicer that tells the printer where the print head should deposit material. Instead of plastic being extruded, however, metal powder is deposited or rolled on in thin layers and a glue-like binding substance is ejected from the print head on top of each layer. The alternating layers of powder and binder fuse together and begin to build upwards to create the object. Some printers have overhead heaters that further allow the layers to dry and the binding solution to melt the powder in the areas where it was deposited. This process is repeated until all the layers of the object are complete from the bottom up. This process can take several hours.
Picture from Loughborough University
Powder around your design that is not fused acts as the support and is separated from the model once it’s complete. At this point, the model is quite fragile as most of it is filled with air and very porous. You can then place the finished model in a curing oven where it is kept at 350 Fahrenheit for 24 hours. This heat evaporates any moisture and hardens the glue binding the layers of metal powder together. After it’s fully hardened and cooled, it can be filled with material like bronze filler which gives the model strength. Without filling the inside with another metal substance, the model is still quite weak and is not recommended for creating functional parts. The binder jetting does allow for colour printing and also works with polymers and ceramic material. The process is fairly fast compared to other additive manufacturing methods but post processing can take up a lot of time.
2. Powder bed fusion The process of powder bed fusion is very similar to metal binder jetting except instead of a binder being deposited to fuse layers of metal powder together, a high temperature laser or electron beam is used. The laser increases the temperature of the powder in the areas where the design is being built, fusing the metal powder and creating a solid layer. This process continues until the entire model is complete! Powder Bed Fusion can be performed using one of a number of different techniques, including: Selective laster sintering, (SLS), Selective laser melting (SLM), Direct metal laser sintering (DMLS), and Electron beam melting (EBM). So what’s the difference between all these methods?
- Selective Laser Sintering (SLS): Uses a laser to fuse layers of metal powder together.
- Selective laser melting (SLM): Goes a step further than fusing the powder together and actually melts the powder. This works well with composites made of one material like pure titanium or steel vs. many mixed together like most plastics.
- Direct metal laser sintering (DMLS): Uses the same process as SLS but is used when referring to the process of sintering metal alloys vs. plastic, glass, and ceramics. If you want to know more about DMLS, Spencer Wright, a manufacturing guru documented his experience printing titanium parts in detail.
- Electron Beam Melting (EBM): Layers of powder are fused together using an electron beam to melt metal powders. Support structures are necessary for this method. This method provides a lot of strength to the model because of the even temperature of the layers during the fusion.
3. Directed energy deposition This process uses two different types of material – metal wire or metal powder. A nozzle that moves in multiple directions (4-5 axis) extrudes metal powder or wire material layer by layer. Once the material is deposited, it is melted with a laser or electron beam. This process continues and the object is built up layer by layer. Although this process is usually used to repair and maintain existing metal material, it can be used to create objects from scratch.
When will Desktop Printers 3D Print Metal?
Unfortunately, most true metal 3D printers are over $250,000 which is a high price to pay for something that you’d like to print a few forks and household items with. One maker decided to take things into his own hands and build a working prototype of a desktop metal 3D printer for $2. His prototype uses electroplating to create metal objects. Another company, MatterFab is working on a low price metal 3D printer for home use that utilizes laser technology to melt the layers of metal powder together to create an object. They are in the midst of testing their prototypes with early users so they are not yet available to the public. It seems like there is innovation going on in desktop metal 3D printing, but nothing at a reasonable price that is ready for market yet.
Metal Infused 3D Filaments
Ok, so you may not be able to 3D print with metal at home yet, but there are a number of companies that produce FDM- compatible filament that are infused with metal powders, giving the appearance and some of the physical properties of metal. Here are a few to check out from our friends at Proto Pasta:
Since the base of most metal filaments is PLA or ABS – you can easily print with them on your FDM printer. However, before you get started there are a few things to note. The powdered metal that is mixed in these filaments is more coarse than regular filament and may wear harder on your printer nozzle, depending on what type of material your nozzle of made out of. This wear on your nozzle may increase the diameter of your nozzle which means it will need to be replaced more often. To avoid this, Proto Pasta recommends wear resistant nozzles made of brass with a wear-resistant coating on top. If you’re interested in 3D printing with metal, this is definitely an affordable alternative to buying a metal 3D printer.
As this technology advances, we will start to see more and more different filaments with infused material as well as advances in 3D printing hardware to support these new filaments.
Want to give it a try?
Check out these free designs on Pinshape that will print perfectly with 3D printed metal filament:
Experience printing with metal infused filaments? Post your comments and tips below!