How Do 3D Printers Work?

How Do 3D Printers Work?

In recent years, a new technology that promises to bring about great economic changes at both the producer and consumer level has been gaining ground while making headlines in the process. 3D printing, a process for making three-dimensional objects using instructions from digital computer files, has the potential to revolutionize the way parts and products are made. Following is a basic introduction to this intriguing process and the different technologies that make it possible.

The Basics of 3D Printing

Though different types of 3D printers can differ considerably, they all operate on a common principle known as additive manufacturing. Traditional manufacturing methods, such as machining blocks of metal, rely on the removal of material to create objects. Additive manufacturing systems, conversely, build objects up layer by layer from raw materials in accordance with instructions from computerized printing files. This type of manufacturing produces less waste than traditional methods while allowing many different objects to be created using a single machine.

Common 3D Printing Technologies

Since it was first invented, 3D printing has become a diverse field which encompasses many different technologies. Below are descriptions of some of the most common types of 3D printing used by both industrial manufacturers and everyday consumers.

Fused Deposition Modeling (FDM)

By far the most common 3D printing technology at the consumer level, FDM involves the extrusion of heated plastic filament through a moving nozzle. As the nozzle moves, it lays down layers of material that eventually form a 3D-printed object. FDM printers have the advantage of being compact, easy to operate and relatively inexpensive. PLA and ABS, two very common plastics, are widely used in FDM printing. Nylon, ASA and carbon fiber filaments have also been developed for FDM printers. Among the companies that make FDM printers, two of the industry leaders are Ultimaker and MakerBot. These two companies have been instrumental in putting 3D printing technology into the hands of consumers and enabling people all over the world to design and make their own printed objects.

Selective Laser Sintering (SLS)

Unlike FDM machines, SLS printers lay down layers of powdered material combined with a binding agent. A precision laser is then used to sinter the layers together, resulting in a 3D-printed object. Heavy industrial manufacturers are the primary users of this technology at the moment, as the printers themselves are quite large and can cost well in excess of $100,000. However, SLS printers are gradually becoming smaller and more affordable. Several companies are even working to create desktop SLS printers. SLS machines can be used to sinter powdered metals, allowing for more durable industrial parts to be printed. Though metal SLS printers are currently unavailable at the consumer level, new models such as the popular Sinterit Lisa have recently brought plastic powder printing to the desktop format.

Stereolithography (SLA)

Though FDM and SLS printers are more widely used, the influence of SLA technology on 3D printing is almost impossible to understate. This is because SLA was the original additive manufacturing process patented by 3D printing pioneer Chuck Hall. To create 3D objects, SLA printers focus ultraviolet light onto the surface of liquid resins. Through a photochemical reaction, the UV light hardens the resin. With repeated application of light, this process can create layer after layer of hardened resin, eventually resulting in a 3D print. Since the invention of SLA printing, a variety of resins with different material properties have been developed to make this printing technology useful in a wide range of applications. The Formlabs Form 2, for example, can be loaded with resins that mimic materials such as rubber and polypropylene.

Digital Light Processing (DLP)

DLP printers are, in principle, remarkably similar to SLA machines. The substantial difference between the two lies in how the light is applied to the liquid resin. In SLA printers, a source of UV light is moved across the liquid's surface quickly to create the shape of each layer in a print. DLP printers still apply UV light to a photoreactive liquid resin but use a larger UV projection device to harden the full shape of an individual layer all at once. As a result, DLP is faster than SLA, particularly for large prints. Though faster, DLP produces prints at lower resolution levels than SLA. DLP technology is relatively new, but manufacturers are already creating many different printers that take full advantage of it. At the moment, the Flashforge Hunter is one of the leading DLP 3D printers on the market.

Although these technologies dominate the 3D printing market at the moment, substantial advancements in both materials and printing techniques are made each year. With these advances has also come widespread adoption of additive manufacturing technology. In fact, by 2018, there may be as many as one million 3D printers in the hands of consumers around the world.