As the name implies, additive manufacturing is the process of creating objects by adding one fine layer of material at a time.
The first commercialized 3D printing method, stereolithography, was invented and patented in the early 1980s by 3D Systems. The process solidifies ultraviolet light-sensitive polymer using a laser. The company’s SLA-1, the first commercially available additive manufacturing system in the world, went into production in 1987.
In the years since, the methods have been refined and further developed. Materials have expanded beyond plastics and other polymers to include metal, ceramics and even biological matter.
Currently, there are seven categories of additive manufacturing techniques:
Unique among other techniques, binder jetting does not use heat during the materials fusing process. A print head moves along the x and y axes and deposits alternating layers of the build material, usually powder, and a binder, typically liquid.
Directed Energy Deposition
This method deposits material, melted with a laser or electron beam, on a surface where it solidifies. It can be used with polymers and ceramics, but is typically used with metals, either in powder or wire form. DED is also known as laser metal depositions, 3D laser cladding or direct light fabrication, and is mainly used for repairing or maintaining existing parts by adding material where needed.
Power Bed Fusion
The power bed fusion process encompasses techniques such as direct metal laser sintering, electron beam melting, selective heat sintering, selective laser melting and selective laser sintering. In all these cases, a heat source is used to melt and fuse together material powder, either plastic or metal, that has been spread in a thin layer across the build chamber. The build platform is gradually lowered as each layer is fused.
Sheet lamination processes build objects by stacking and laminating thin sheets of material through bonding, ultrasonic welding or brazing. Laser cutting or CNC machining is used to shape the object. This method creates the “roughest” objects among additive manufacturing technologies, but takes up less time at a lower cost.
The most popular 3D printers for consumer use employ this method, in which a continuous filament of thermoplastic or composite material is drawn through a nozzle, where it is heated and deposited layer by layer.
This relatively new 3D printing technique sprays hundreds of liquid photopolymer droplets, a wax-like substance, onto a surface, where it is then cured using ultraviolet light. It works similarly to an inkjet printer, except the process is repeated layer by layer to create a three-dimensional object. Material jetting is consider one of the fastest and most accurate 3D printing techniques.
Stereolithography is a vat photopolymerization technique; the category also includes continuous liquid interface production, solid ground curing and direct light processing. All these methods use special resins called photopolymers, whose molecules rapidly bind together and turn from liquid to solid when exposed to certain wavelengths of light. A light source is used to selectively cure each layer of material on a platform submerged in a vat of the material.
Additive manufacturing was once valued primarily for its ability to quickly turn out prototypes as opposed to mass-producing the projects themselves. It has since evolved to manufacture small, complex parts that are otherwise hard to produce, and has expanded to become a part of the manufacturing process in diverse industries.
For fun example of the former, check out the episode of “Savage Builds,” featuring Adam Savage of “MythBusters” fame, where the famous maker collaborates with Mines faculty and students to 3D-print a wearable suit of Iron Man armor. https://www.minesnewsroom.com/news/savage-builds-kick-mines-and-iron-man-suit
In November 2020, 3D printing solutions company Essentium announced the results of its third annual study, which revealed that the use of large-scale additive manufacturing has more than doubled in the past year for 70 percent of manufacturing companies. The company also found that the number of companies that have shifted to using AM for full-scale production runs of hundreds of thousands of parts has doubled from 7 percent in 2019 to 14 percent in 2020.
“During the Covid-19 pandemic, AM proved it can step in to make quantities of supplies at scale, or at least the mold to make the product, to keep the assembly lines moving. The survey found 57 percent of manufacturers increased 3D printing for production parts to keep their supply chains flowing during the crisis. 3D printing investment plans have also changed at many companies: 24 percent of respondents have gone all-in; 25 percent of manufacturers are ramping up to meet supply chain needs; and 30 percent of respondents are evaluating industrial-scale 3D printing to fill supply chain gaps.”
According to Essentium, the survey highlighted the demand for more reliable and affordable 3D printing materials. Manufacturers, in large part, agree that 3D printing technology can eventually save billions in production costs and give companies a clear competitive advantage in the next five years.
One example of 3D printing used on an industrial scale is the Amazea, an underwater scooter manufactured by the German company Jamade. Three-quarters of the Amazea—its body and front parts—are produced using large-format extrusion 3D printing technology, as opposed to traditional casting or injection molding.
In a January 2020 article for Deloitte, General Motors’ director of additive design and manufacturing writes that the company is actively investing in developing its additive manufacturing capabilities beyond prototyping, because it sees value in two areas in particular.
“First, AM can help make lightweight versions of many nonvisible, structural components. Lightweighting is vital to meet fuel-economy regulations and achieve longer ranges for our electric vehicles. Second, AM can deliver more flexibility to make unique designs.”
The Alliance for the Development of Additive Processing Technologies, an industry-academia consortium based at Colorado School of Mines,seeks to help its member companies optimize their additive manufacturing processes, materials and parts by using data informatics and advanced characterization technologies—determining exactly how and why a product has the properties it does.
ADAPT members include companies of all types and sizes: from industry stalwarts such as Ball Aerospace, Lockheed Martin, Faustson, Milwaukee Tool, even the first 3D printer manufacturer, 3D Systems, to Colorado startups. “ADAPT is going to make Colorado the center of the universe for this knowledge, and we’re starting to see that already,” said Tom Bugnitz, CEO of Manufacturer’s Edge, a nonprofit working to boost the competitiveness of the state’s 6,000 manufacturers through technical assistance and by fostering government and university partnerships.
“Larger companies are embracing additive manufacturing now, and it will trickle down soon enough,” said Craig Brice, a member of ADAPT’s leadership team and director of Colorado School of Mines’ Advanced Manufacturing Program. “The technologies are starting to show benefits in terms of lead time and cost, which will drive most companies to eventually adopt.”