You can 3D print out of metal using various methods, such as powder bed fusion, directed energy deposition, binder jetting, and metal extrusion. These methods allow you to create complex and customized metal parts for various applications, such as aerospace, automotive, medical, and jewelry. In this article, we will explore the advantages and disadvantages of each method, as well as some examples of metal 3D printing projects.
Powder bed fusion is a method that uses a laser or an electron beam to selectively melt and fuse metal powder particles together, layer by layer, to form a solid object. The most common types of powder bed fusion are selective laser melting (SLM) and electron beam melting (EBM).
The advantages of powder bed fusion are:
It can produce high-quality and high-strength metal parts with intricate geometries and fine details.
It can use a wide range of metal materials, such as titanium, aluminum, steel, nickel, and cobalt alloys.
It can reduce material waste and production costs, as the unused powder can be reused.
The disadvantages of powder bed fusion are:
It requires high temperatures and high-energy sources, which can cause thermal stresses and distortions in the printed parts.
It requires post-processing, such as removing support structures, polishing, and heat treatment, to improve the surface finish and mechanical properties of the printed parts.
It has a limited build volume and a slow printing speed, which can limit the scalability and productivity of the process.
Some examples of powder bed fusion projects are:
GE Aviation’s fuel nozzles for jet engines, which are 25% lighter and five times more durable than conventional ones.
SpaceX’s SuperDraco thrusters for the Dragon spacecraft, which are made of Inconel, a high-performance nickel alloy.
Adidas’s Futurecraft 4D shoes, which have a lattice structure for the midsole, designed to provide optimal cushioning and stability for the wearer.
Directed energy deposition is a method that uses a nozzle to deposit metal powder or wire onto a substrate, while a laser or an electron beam melts and fuses the material, creating a solid object. The nozzle can move in multiple directions, allowing the creation of freeform shapes and adding material to existing parts.
The advantages of directed energy deposition are:
It can repair or modify existing metal parts, such as turbine blades, molds, and tools, by adding material to worn or damaged areas.
It can create large and complex metal parts, such as rocket engines, aircraft wings, and ship propellers, by depositing material onto a large substrate or a rotating platform.
It can use multiple materials in a single print, creating parts with graded or mixed properties, such as corrosion resistance, wear resistance, or thermal conductivity.
The disadvantages of directed energy deposition are:
It has a low resolution and a rough surface finish, which can affect the accuracy and aesthetics of the printed parts.
It can cause defects and porosity in the printed parts, due to the uneven heating and cooling of the material.
It requires post-processing, such as machining, grinding, and welding, to improve the quality and functionality of the printed parts.
Some examples of directed energy deposition projects are:
NASA’s copper rocket engine combustion chamber, which was printed in one piece, reducing the number of parts and joints, and increasing the performance and reliability of the engine.
Siemens’s gas turbine blades, which were printed using a nickel alloy, and tested under extreme conditions, such as high temperatures, pressures, and rotational speeds.
MX3D’s steel bridge, which was printed using robotic arms, and spans over a canal in Amsterdam, showcasing the potential of metal 3D printing for architecture and construction.
Binder jetting
Binder jetting is a method that uses a print head to deposit a liquid binder onto a bed of metal powder, layer by layer, to form a green part. The green part is then sintered in a furnace, where the binder is burned off and the metal particles are fused together, creating a solid object.
It can produce metal parts with high resolution and smooth surface finish, without the need for support structures or post-processing.
It can use a variety of metal materials, such as stainless steel, bronze, iron, copper, and gold.
It can print multiple parts simultaneously, increasing the throughput and efficiency of the process.
The disadvantages of binder jetting are:
It has a low density and a low strength, compared to other metal 3D printing methods, due to the presence of binder and porosity in the printed parts.
It requires a separate sintering step, which can cause shrinkage and deformation in the printed parts, affecting their dimensional accuracy and stability.
It has a limited color range and a dull appearance, due to the oxidation and discoloration of the metal during the sintering process.
Some examples of binder jetting projects are:
ExOne’s metal 3D printed molds, which are used for sand casting and investment casting, reducing the lead time and cost of producing metal parts.
Desktop Metal’s metal 3D printed jewelry, which are designed using generative algorithms, and printed with fine details and intricate patterns.
HP’s metal 3D printed gears, which are printed with a high degree of precision and durability, and used for automotive and industrial applications.
Metal extrusion
Metal extrusion is a method that uses a heated nozzle to extrude a metal filament, which is a metal powder mixed with a plastic binder, onto a build platform, layer by layer, to form a green part. The green part is then debound and sintered, similar to binder jetting, to create a solid object.
The advantages of metal extrusion are:
It is similar to the conventional fused deposition modeling (FDM) method, which is widely used for plastic 3D printing, making it easy to use and accessible for hobbyists and makers.
It is relatively low-cost and low-maintenance, as it does not require expensive equipment or materials, or complex settings or calibration.
It can print metal parts with complex geometries and internal features, such as hollow structures, channels, and cavities, which are difficult to achieve with other metal 3D printing methods.
It has a low resolution and a poor surface finish, which can affect the quality and appearance of the printed parts.
It can cause warping and cracking in the printed parts, due to the thermal expansion and contraction of the material during the printing and sintering processes.
It has a limited selection of metal materials, such as stainless steel, copper, and bronze, which are compatible with the extrusion process.
Some examples of metal extrusion projects are:
Markforged’s metal 3D printed end-use parts, which are printed with a continuous carbon fiber reinforcement, increasing the strength and stiffness of the metal parts.
BASF’s metal 3D printed prototypes, which are printed with a metal-polymer composite filament, and used for testing and validation of new designs and concepts.
MakerBot’s metal 3D printed art, which are printed with a bronze-infused filament, and polished to reveal a shiny and metallic surface.
Conclusion
Metal 3D printing is a rapidly evolving and expanding field, with various methods and applications. Each method has its own advantages and disadvantages, depending on the desired outcome and the available resources. By understanding the different methods, you can choose the best one for your metal 3D printing project, and create amazing and innovative metal parts.
