What You Should Know About Additive Manufacturing
Looking at the technologies, how they work, and what’s best for you
Additive manufacturing describes the process of building a 3D object layer upon layer on a build platform until the final product is finished. There are pros and cons for each of the seven main types of additive manufacturing. Here is a brief overview of the different types of additive manufacturing to help you choose the proper method for your business. ISO/ASTM52900-15 defines the seven processes as:
- Binder Jetting: Droplets of liquid binder are deposited on a bed of powdered material
- Directed Energy Deposition: Molten metal is simultaneously deposited and fused
- Material Extrusion: Molten thermoplastic (filament) is deposited through a heated nozzle
- Material Jetting: Droplets of liquid material are deposited on a build platform
- Powder Bed Fusion: Powder particles are fused by a high-energy source
- Sheet Lamination: Individual sheets of material are laminated together and cut to shape
- VAT Photopolymerization: Liquid photopolymer (resin) is jetted and cured by light
|Additive manufacturing opens the design space to unique,
complex, and innovative creations.
Source: Euclid Group
Binder jetting is among the most common additive manufacturing processes. This method is like inkjet printing, but it jets a binder (glue) into a powder material instead of ink. Binder jetting uses a variety of materials, including ceramics, glass, gypsum powder, metal, plastics, and sand.
Directed Energy Deposition
Direct energy deposition (DED) creates parts by layering beads of molten material (usually metal). The material is continuously pushed through a nozzle and melted by a laser, electron beam, or arc at the point of deposition, where it cools and solidifies.
Material extrusion works just like a hot glue gun. The spooled material feeds into the printer from a coil where the tip of the nozzle heats and melts the material. The molten material is then extruded layer by layer onto the build platform, where it cools and solidifies to form the object. However, since the heating elements aren’t powerful enough to melt high-density materials like metal, material choices are limited to using only thermoplastics, which may not have adequate durability for some applications.
This technology is like binder jetting, but it deposits droplets of material onto the build platform instead of jetting a binder onto a bed of powder. It takes longer to build objects this way because they are built one droplet at a time. Due to the variety of technologies in material jetting, a wide range of materials are available. The most common are photopolymers, flexible plastics, casting wax, metals, and ceramics.
Powder Bed Fusion
Powder Bed Fusion (PBF) produces parts using an energy source (electron beam or laser) to selectively melt or sinter powdered particles together to create an object. Powdered materials are heated to just below the melting point and then are spread over the build platform in a thin layer. The laser or electron beam projects energy across the powder bed, fusing particles together to form a single cross-section of the final object. After each layer, the build platform is lowered, and the process is repeated. Each new layer is fused to the previous layer to make one object.
This is an AM process that stacks thin sheets of material and bonds them together through ultrasonic welding, bonding, or brazing. Because sheet lamination works in layers, it provides manufacturers with the ability to layer various materials at a lower cost than other additive manufacturing processes. While this is cost effective, it usually requires some post-process finishing that is time-consuming and is limited to materials that can come in sheets (metal, paper, and plastic). Since excess material needs to be removed once lamination is complete, there is some waste involved with this process.
This process is also like powder bed fusion except, instead of a bed of powder, it uses a vat of photopolymer resin that is hardened in layers by an energy source (laser or UV light). Once a layer is complete, more resin is added to make the next layer. Although resin can be quite expensive, VAT polymerization can construct objects quickly, provides a high degree of accuracy, and produces a good finish. Despite its benefits, VAT polymerization manufacturers are limited to using photopolymer resins and post-process finishing is usually required.
Keypoint Intelligence Opinion:
Advantages of additive manufacturing include affordability, streamlined production, high quality, being short volume friendly, and a reduced risk when prototyping proof of concept.
So, which type of additive manufacturing is right for you? The short answer is “It depends.” Prior to selecting an additive manufacturing method, it’s important understand needs and requirements. The above descriptions merely scratch the surface of the entire additive manufacturing spectrum. Whatever your need, there is an additive manufacturing process that can help—but there’s no silver bullet. Each technology has advantages and disadvantages, and our industry analysts stand ready to help you navigate the additive manufacturing jungle.
Log in to the InfoCenter to view our full analyses on Additive Manufacturing and learn more about each process in the Functional & Industrial Printing Advisory Service. If you’re not a subscriber, just send us an email at firstname.lastname@example.org for more info.