Introduction to 3D Printing

3D printing, also referred to as rapid prototyping, is a computer-controlled manufacturing process that creates three-dimensional physical objects from the data stored in a digital file. It is an additive manufacturing process, meaning it uses technologies that add layers of material until the finished product matches the data in the digital model. Engineers and designers use Computer Aided Design (CAD) software to draw, modify, and analyze the model in a digital space enabling the creator to design the model’s dimensions, material, and color before its manufacture. 

The History of 3D Printing and How 3D Printers Work

Hideo Kodama, a Japanese engineer, invented the earliest predecessor to modern 3D printers in the early 1980s. He applied for a patent for a technology that uses ultraviolet light to harden a photosensitive polymer (photopolymer) and develop a product in a layer-by-layer approach. 

A polymer is photosensitive if its structure or other properties change when exposed to light. Photopolymerization is a process that takes advantage of this by using ultraviolet light to harden a liquid polymer into a solid. This technology is the backbone of early 3D printing processes. It paved the way for stereolithography (SLA), created by Charles Hull and patented in 1986. 

SLA, also known as resin 3D printing, is a process that uses a beam of ultraviolet light to “cure” or harden a vat of liquid polymer and create products by layer. The polymer is first rinsed with a solvent before being subjected to photopolymerization. Stereolithography is now considered to be amongst a group of 3D printing processes known as vat polymerization.

SLA served as a predecessor to yet another technology known as Selective Laser Sintering (SLS). SLS uses a laser to heat powdered polymers and synthesize them into layers of solid material. The term “sintering” refers to heating a powdered mass below its melting point and forming it into a solid object. Sintering improves the integrity of the material.

The most common type of 3D printing used today is Fused Deposition Modeling (FDM), developed by Scott Crump. These printers melt a thermoplastic filament and squeeze (or extrude) it through a nozzle that moves horizontally and vertically over a build tray. The final product is created layer by layer. The most widely used filaments are ABS (acrylonitrile butadiene styrene) and PLA (polylactic acid). The small 3D printers that can fit on a desktop, aptly known as desktop 3D printers, are typically FDM printers.

What Is 3D Printing Used For?

Over the last twenty years, 3D printing has become more accessible due to the falling prices of 3D printers. Simultaneously, there has been an increase in the quality of 3D-printed goods, and printing has become easier. Additionally, it is now possible to print a much wider variety of materials, including graphite, carbon fiber, graphene, paper, powders, glass fiber, and plastics. These benefits have given 3D printing several real-world uses in manufacturing, medicine, and construction. 

Manufacturing

3D printing has revolutionized prototyping in the manufacturing industry. Companies can create prototypes with shorter lead times and a much smaller cost than traditional prototyping methods. It is possible to make an accurate and high-quality prototype in a matter of hours. This technology is best suited for fabricating items at a smaller scale where traditional methods would not produce adequate economies of scale.

Medicine

The medical industry uses the versatility of 3D printing technologies to create prosthetics and implants that can be custom-created for specific patients. Moreover, sterile surgical instruments can be manufactured cheaply using 3D printing.

The pharmaceutical industry can create cost-effective pills using binder jetting, a 3D printing process that uses powder materials as the raw material.

Another use case is bioprinting. Bioprinting is a 3D printing process that uses “bio-ink” to assemble layers of living cells through extrusion, inkjet printing, or laser-assisted printing. The resulting structure is treated with UV light or an ionic solution. This process creates living tissues, blood vessels, and, potentially, entire organs that are identical to body parts. 

Printed biomaterials can replace animal testing in the pharmaceutical industry to investigate the effects of drugs on the human body. This process will be more ethical and have greater relevance to the human body. As bioprinting technology improves, 3D-printed organs can shorten the waiting lists for organ transplants. 

Medical research and education can benefit from using bioprinting to create accurate anatomical models. These models have been used to perform surgical procedures faster and safer by having doctors practice operations on these replicas before performing them on patients. 

Construction

3D printing offers an opportunity to lower labor costs and create less waste while constructing buildings faster, easier, more accurately, and with improved durability. 

On-site construction 3D printing utilizes gantry systems and an industrial robotic arm with a 3D printer attached to it that extrudes concrete. Alternatively, the materials are created in a separate facility and assembled later on-site. 

One major drawback of construction 3D printing is that a limited number of construction materials can be used. The same printer may not be able to print a large variety of different materials. The printers also have a high upfront cost that makes their use prohibitive for companies that cannot afford them. 

The use of 3D printing technology in this industry is relatively niche. However, as the technology improves and extrudable building materials are developed, construction 3D printing may become a mainstream feature of the industry. 

Conclusion

3D printing, or rapid prototyping, is a technology that can use the information stored in digital files to create real-world objects. 3D printing technology has been adopted in various industries, including manufacturing, medicine, and construction.