Metal 3D Printing: An Overview Of The Technology And Its Process

What is Metal 3D Printing?

Metal 3D printing, also known as additive manufacturing or metal additive manufacturing, creates three-dimensional items by selectively depositing or melting metal powders layer by layer. Electron beam melting (EBM) and selective laser melting (SLM) are two approaches used to accomplish this.  To conventional manufacturing techniques, metal 3D printing offers enhanced design flexibility, intricate geometries, and great precision in producing complex and customized metal parts.

How Does it Work?

Metal 3D printing, also known as additive manufacturing, follows a sequential process. It begins with creating a digital model using 3D computer-aided design (CAD) software. The model is then sliced into thin layers, and metal powders are prepared for printing. Using techniques like Selective Laser Melting (SLM) or Electron Beam Melting (EBM), the printer selectively melts and fuses the metal powder layer by layer, following the sliced design. This layer-by-layer approach continues until the entire object is completed. Post-processing steps, such as removing support structures and applying heat treatment or surface finishing, may be conducted. The result is a fully formed, bespoke metal object with intricate details and precise specifications.

TYPES OF 3D METAL PRINTING

There are five main types of 3D metal printing technologies commonly used in the industry. It includes selective laser melting, electron beam melting, direct metal laser sintering, binder jetting, and directed energy deposition.

Selective Laser Melting (SLM)

A popular 3D metal printing technique called Selective Laser Melting (SLM) uses a powerful laser to fuse and melt metal powders selectively, allowing for the production of fully solid metal components with incredibly complicated geometries.

During the SLM process, it uniformly applied a thin coating of metal powder to the build platform. The laser then scans the powdered layer, melting particular regions of the layer under the digital design.
For applications requiring complex designs, great accuracy, and strong structural integrity, SLM is a preferred option because of its ability to precisely control the laser and produce highly detailed and customized metal components with exceptional mechanical qualities.

For applications requiring complex designs, great accuracy, and strong structural integrity, SLM is a preferred option because of its ability to precisely control the laser and produce highly detailed and customized metal components with exceptional mechanical qualities.

(Fig.1: JLC3DP Design Guidelines for SLM)

Electron Beam Melting (EBM)

Electron Beam Melting (EBM) is an advanced metal 3D printing technology that shares similarities with Selective Laser Melting (SLM) but utilizes an electron beam instead of a laser to melt and fuse metal powders.

In EBM, a focused electron beam scans and selectively melts the metal powder bed, layer by layer, according to the digital design. This process ensures the precise melting and fusion of the metal particles, resulting in the production of large-scale metal components with excellent mechanical properties. EBM offers advantages such as high build speeds, reduced residual stresses, and the ability to manufacture parts with complex geometries.

It is particularly well-suited for applications that require the production of sturdy, intricate, and functional metal parts, making it a preferred choice in industries such as aerospace, automotive, and medical.

Direct Metal Laser Sintering (DMLS)

One additive manufacturing method that is closely similar to Selective Laser Melting (SLM) is Direct Metal Laser Sintering (DMLS). By selectively sintering metal powders with a lower-power laser, DMLS produces the desired object by fusing and bonding the powders together layer by layer. This technology enables the very precise and detailed manufacturing of small-scale production parts and working prototypes.

The benefits of DMLS include its versatility in handling various metal materials and its capacity to create intricate geometries. Because of its adaptability and capacity to produce sturdy metal parts, it is a preferred option in sectors including healthcare, automotive, and aerospace where small-scale production and quick prototyping are essential.

Binder Jetting

Binder jetting is an additive manufacturing process that involves selectively jetting a liquid binder over layers of metal powder, thereby gluing the powder particles together. This process involves spreading a thin coating of metal powder on the build platform, then using a print head to deposit liquid binder droplets into particular sections of the platform to solidify them. Until the thing is entirely constructed, this process is repeated layer by layer.  Remove the binder and fuse the metal particles, creating a thick and solid metal component, the product is usually put through post-processing techniques like sintering after printing.

Binder jetting is a metal 3D printing technique that offers significant advantages in terms of printing speed and cost-effectiveness compared to other metal additive manufacturing methods. The process involves selectively jetting a liquid binder onto layers of metal powder, creating a bond between the particles. This allows for the creation of complex geometries and intricate details.

One of the key advantages of binder jetting is its high printing speed. The ability to rapidly deposit the binder onto the metal powder enables faster production times compared to other metal 3D printing technologies. This makes binder jetting particularly suitable for applications where time is a crucial factor, such as in tooling, where quick turnaround is essential.

Cost-effectiveness is another notable advantage of binder jetting. The technology utilizes less expensive metal powders, reducing material costs compared to other metal 3D printing methods. Additionally, binder jetting can achieve high material utilization rates, minimizing waste and further contributing to cost efficiency.

Binder jetting finds applications in various industries. In tooling, it allows for the production of molds and fixtures with intricate internal channels and complex shapes, enabling faster and more efficient manufacturing processes. In the jewelry industry, binder jetting enables the creation of customized and intricate designs with high precision. Additionally, binder jetting is commonly used in prototyping applications, where speed, cost, and moderate material properties are critical considerations for quickly iterating and validating designs.

However, it is important to note that while binder jetting offers advantages in terms of speed and cost-effectiveness, the mechanical properties of the final printed parts may be lower compared to other metal 3D printing methods such as SLM or EBM. Therefore, binder jetting is often used in applications where moderate material properties are sufficient for the intended use.

Directed Energy Deposition (DED)

With directed energy deposition (DED), a focused energy source, like a laser or electron beam, metal powder, or wire feedstock is precisely deposited onto a substrate. Numerous uses are made possible by this method, such as coating, large-scale metal component additive manufacture, and repair.

During the deposition of the metal feedstock onto the substrate, the energy source in DED melts it. The concentrated energy ensures exact control over the heat input, allowing for layer-by-layer deposition. Because of its adaptability, DED may be used to repair damaged metal parts by adding material to help them regain their previous form and functionality.

Another application of DED is coating. By depositing layers of metal onto a substrate, DED can create protective coatings that enhance the surface properties of the component, such as wear resistance or corrosion protection.

DED is also utilized in the additive manufacturing of large-scale metal components. By continuously depositing and solidifying layers of metal, complex structures can be built up, allowing for the creation of custom-designed parts with specific geometries and properties.

One of the advantages of DED is its capability to work with a wide range of materials, including various metals and alloys. This versatility enables the production of components with tailored material properties to meet specific requirements.
DED is often employed in industries such as aerospace, automotive, and energy, where the repair, coating, or fabrication of large-scale metal components is crucial. The ability to add material directly to the substrate provides a cost-effective and efficient solution for repairing or enhancing existing parts, as well as manufacturing new components with complex geometries.

Conclusion

To sum up, metal 3D printing is a revolutionary technology that makes it possible to produce precise, customized, and complex metal components. Metal objects can be created layer by layer using a variety of processes, including Direct Metal Laser Sintering (DMLS), Binder Jetting, Electron Beam Melting (EBM), Selective Laser Melting (SLM), and Directed Energy Deposition (DED). This process offers distinct design opportunities and practical advantages. These techniques for additive manufacturing are used in a variety of sectors, including jewelry, automotive, aerospace, and healthcare. With ongoing developments, metal 3D printing has enormous potential to transform production procedures and spur innovation across a range of industries.