It isn’t often that an entirely new fabrication technique is invented for manufacturers.
Casting and molding? Machining, carving, and other subtractive techniques? These have been used in one form or another for millennia.
The Modern Origins of Additive Manufacturing and 3D Printing
Additive manufacturing first emerged as a potential industrial process in the 1980s. The idea was simple—add successive layers of material to create a three-dimensional shape. And you can see examples of the approach in action in the pinch pots and clay sculptures of history. When you think about it, building with brick or adobe is a kind of solid, modular additive process. But modern additive approaches automated the process, taking it beyond the realm of handcrafting. That required two things: an automated way to apply the material and computers to provide digital instructions and control the process.
Since digital technology became widely available, beginning in the 1980s, additive, has advanced rapidly. It’s sometimes referred to as 3D printing, although that refers more accurately to certain additive processes than others. Whatever you call it, it brings with it an entirely new set of constraints and possibilities for manufacturing. Casting and subtractive are proven, established processes—and will always play an important role in the industry—but advances in those processes have been and will continue to be incremental.
Additive Manufacturing and 3D printing give us a fresh start, a new path forward in fabrication—it allows us to reimagine the forms we can make and the materials we can use. Whether you’re talking about rapid prototyping in plastic or printing durable metal components for spaceflight, printing homes in concrete or bio-medical structures for medicine, additive opens the door to a host of applications that were previously unimaginable.
While it has significant limits in scalability and likely always will, it’s important to remember that the additive approach is truly revolutionary for manufacturing—it enables us to make things we could not make any other way. Let’s take a look at where additive fits into the advanced manufacturing landscape today and what experts foresee in the years ahead.
The Challenges and Possibilities of Additive Manufacturing and 3D Printing
What makes additive so disruptive and innovative? In short, there’s no form it can’t make. With casting, you always need to extract the part from the mold. With subtractive, you need to be able to get the tool into the material to create the shape. So, both approaches will always place limitations on the forms we can fabricate.
With additive, if you can design it and model it digitally, the systems can put the material wherever it needs to be. You can create intricate lattice structures as easily as a solid block. Unusual organic shapes don’t provide additional complexity and require no extra time and energy. There are various additive techniques, and each has its pros and cons, but whatever shape you can dream up, there’s an additive approach that can make it.
Additive brings its own challenges, though. For one thing, it’s a linear process that’s difficult to scale. Each system can only make one piece at a time. And it can be quite slow, sometimes taking hours to make a single small object.
Early generations of additive systems placed limits on the size of the objects that could be printed, too—and many still do. The systems can be expensive. And some techniques place distinct limits on the materials that you can print with.
That said, the technology is still young, and it gets faster and cheaper with each new generation. Every few months, someone claims to have built the largest additively manufactured something, and innovators add new materials to the additive arsenal every year. While it started with plastic, today we can 3D print with durable metals, high-performance ceramics, concrete, biomaterials, and more.
In addition, the software available to streamline workflows is getting more sophisticated. For instance, Ansys simulation tools allow you to analyze and optimize your prints before you start printing, and explore what happens if you change the material you print with.
Additive Processes
While the International Organization for Standardization (ISO) defines seven distinct process categories for additive, it can be helpful to think about additive processes in three main categories:
Material extrusion
Material extrusion was conceptually the first type of additive that people thought of, starting with science fiction stories in the mid-20th century. The idea is pretty simple: extrude a material in a liquid state, allow it to harden in place, and keep adding successive layers to create a final form. It works with a range of materials, from plastic, metals, and cement to ceramics, glass, and biomaterials. But the devil is in the details. How quickly will it harden? How well will it hold its shape?
- Material jetting depends on changes in temperature to harden the material and can extrude multiple materials simultaneously.
- Binder jetting adds a binder to the mix to assist with the hardening, accelerating the process, but usually requires post-processing.
- Sheet lamination adds adhesives, welds, or other connectors to the layers and tends to be inexpensive, but usually requires significant subtractive finishing to create a usable part.
Plastic extrusion systems like the Makerbot drove the hobbyist 3D printing craze of the 2000s but were limited by both the durability of the materials used and the small print space. They found use in industry for making scale models and for prototyping—you could print a full-scale version of a new component like a gasket in a few hours, try it out to see how it fit, then fabricate the part in its final material using either metal additive or another process.
Builders are using concrete extrusion to 3D print houses in a fraction of the normal building time, and automated extrusion systems could even enable us to build a colony on Mars before people ever get there.
Photopolymerization Processes
The first patent for an additive system, filed by Hideo Kodama in 1981, was for a photopolymerization system, sometimes known as stereolithography, and this kind of process was another early favorite for hobbyists. Photopolymerization uses a resin that becomes a hard plastic when exposed to UV light. Most of these systems work upside down, with a precise laser hitting the resin from below in the designated pattern, hardening each successive layer as the “platform” retracts or lifts out of the resin pool—thus, the common term, “vat polymerization.” After the shape is formed, it usually needs to be “cured” by exposure to additional UV rays. This process only yields components in plastic, but they can be extremely detailed and intricate, with smooth surface finishes. In industry, you can find them used in everything from hearing aids to custom shoes.
Fusion Processes
Fusion processes use lasers, electron beams, or plasma arcs to fuse materials, usually metal, into the desired shape. Powder bed fusion uses metal powders—similar to those used in casting. Directed energy deposition (DED) and selective laser sintering (SLS) fuse metal wire or powder in place and can be used to repair or add material to existing components because of its formal freedom—it can make any shape of any size as long as the equipment can reach. Thus, it’s been used to fabricate propellers for ships, and more. You’ll often find these processes used in hybrid manufacturing (see below), partly because they usually require subtractive finishing.
What’s Ahead for Additive Manufacturing and 3D Printing
Additive manufacturing and 3D printing provide important new possibilities by themselves. But when combined with other technologies, they hold even more potential. An important part of the future of these processes lies in how they can be combined with other manufacturing techniques and digital technologies.
Hybrid Manufacturing
As revolutionary as additive is, most 3D printed objects still need finishing. This post-processing is usually achieved with subtractive techniques. When additive and subtractive machines are combined in the same enclosure, new possibilities emerge. The LASIMM, a ground-breaking hybrid machine in Spain, was designed so that additive and subtractive techniques are happening in the same place at almost the exact same time.
Generative Design
If additive manufacturing means you can place materials wherever they need to be, then the limitation comes in the design. That is, until we harness the computing power of AI to generate new, data-driven options. With technology like generative design, designers input parameters like size, materials, and manufacturing methods, and the software instantly explores all the possible permutations, giving the designers options they would never dream of and letting them choose the option that best suits their needs.
When combined with additive, generative design can create unusual, organic shapes that simply weren’t possible to fabricate before. It also can replace solid material with lattices, and combine multiple parts into a single part, resulting in lightweighting. General Motors, for example, used these technologies to redesign a seat belt bracket, combining eight separate parts into a single part that is 40% lighter and 20% stronger than the original.
The Takeaway
The emergence of additive manufacturing and the evolution of digital technology means big things for the manufacturing industry. And people are starting to pay attention—the additive manufacturing market is predicted to be worth $51 billion by 2030. Now is the time to consider how your business could benefit from new techniques and technologies. When you’re ready, KETIV is here to talk.