3D printing technology has transformed the manufacturing industry in a variety of ways. It has helped shorten the design cycle, allowed for rapid prototyping, and streamlined the production process. It has also enabled innovation to flourish in the industry.
The benefits of this technology are not limited to this sole industry either. Numerous others such as the healthcare industry and the automotive industry have used 3D printing to produce versatile solutions to problems in their field.
Because of the continued rise and development of this technology, it has become more affordable and more accessible to businesses as well as individuals. The problem is, there are now a number of 3D printing solutions to choose from, the main ones being FDM, SLS, and SLA. Which type of 3D printing technology is the right solution for your application?
Choosing the right technology for your project will depend on several factors. Each type has its own pros and cons, the kinds of materials it can use, and the level of expertise required. Not to mention, the solution that you choose will have an effect on the characteristics of the object produced. It’s safe to say that learning the ins and outs of each 3D printing technology available is imperative if you want your project to be successful. Below is a short but definitive guide to the most popular 3D printing solutions available:
Fused Deposition Modeling (FDM)
This additive manufacturing method is also known as fused filament fabrication or FFF. It is the most popular form of 3D printing because it is considered the most affordable and accessible to the consumer level.
How does FDM work? The printer uses a plastic filament which is extruded through a heated nozzle and deposited layer by layer on the printer bed. You can use a wide range of thermoplastics with this technology; generally, these are ABS (Acrylonitrile Butadiene Styrene), PLA (Polylactic Acid) and Nylon (Polyamide).
This technology is suitable for printing basic prototypes and architectural or model mock-ups quickly. Plus, FDM 3D printers and materials are very affordable which makes them the most widely used 3D printing method among consumers.
However, FDM is not ideal for printing complex designs or parts with intricate features. It has the lowest resolution and accuracy, specifically when compared to other additive manufacturing methods. The surface texture is typically rough. It is possible to produce objects with high-quality finishes provided they are subjected to chemical or mechanical polishing after printing.
Stereolithography or SLA was the first 3D printing technology ever discovered, way back in the 1980s. This additive manufacturing method features a laser beam that solidifies liquid resin, turning it into hardened plastic, through the process of photopolymerization. The 3D printer applies a thin layer of liquid resin on the build area. Then, a 2D section of the object is drawn by the laser.
Afterward, a new thin layer is applied and then a new section is drawn. These steps are repeated until the entire 3D object is complete. When the object has been completely printed, it is soaked in liquid resin to remove any support structures that were built along with the object.
Compared to the other 3D printing technologies, SLA has the highest accuracy and resolution. It also produces objects with the smoothest finish. But the biggest advantage of SLA is in its versatility. There is a wide range of photopolymer resin formulations available that offer different thermal, mechanical, and optical properties. This makes it the ideal option for companies looking to print highly detailed prototypes.
SLA is typically used to create molds, patterns, and functional parts in various industries such as engineering, education, and jewelry. The main drawback of using SLA is that the printers can be expensive, the resins even more so.
Selective Laser Sintering (SLS)
Selective Laser Sintering is a 3D printing technology that is usually only utilized by professionals. That being said, consumers can still utilize this kind of technology through a 3D printing service online.
So, what is SLS? This additive manufacturing method is similar to SLA in that it also uses a laser to “print” an object. However, in this case, the laser sinters, melts, or fuses powder particles together to build an object. Take note that the power of the laser will determine the type of material that can be used by an SLS printer.
How does it work? A thin layer of powder is swept across the build stage by a recoater – sort of like a knife spreading butter on a piece of bread. The laser then sinters the powder particles together into the first cross-section of the design. The build stage is then lowered one layer down in depth before a new thin layer of powder is swept across by the recoater. The laser then sinters the powder particles to build the second cross-section of the design. This process repeats itself until the object is completed.
Because there are unfused powder particles surrounding the “printed” layers, there is no need to support structures to be built. This makes SLS the ideal method for building complex geometries and interlocking objects. Materials used in SLS 3D printing include Polyamide (Nylon), Polystyrenes, Thermoplastic Polyurethane (TPU), and Metal.
While some of the materials such as nylon are affordable, SLS printers are very expensive, starting at around $10,000. These printers are large; they are considered “benchtop” machines. But that also means they print much faster and can build large-scale models.
SLS-printed products are typically strong yet flexible, with superior abrasion and chemical resistance.
Direct Metal Laser Sintering (DMLS)
Direct Metal Laser Sintering is one of the most advanced 3D printing technologies today. Using a laser, it “prints” an object by fusing finely powdered metal.
How does it work? The DMLS printer hopper is filled with metal powder which dispenses a thin layer of the powder onto the build platform. The laser selectively sinters the powder to create the first cross-section of the object. The process is repeated layer by layer until the object is completed. Once the part is left to cool, any loose powder in the build area is removed.
DMLS allows you to print objects made of pure metals or metal alloys. There is a wide range of materials available including steel, stainless steel, aluminum, titanium, nickel alloys, cobalt chrome, and precious metals.
Any unused particles can be reused in future builds. Moreover, DMLS enables the creation of strong, functional parts with good mechanical properties, comparable to parts that are cast in the same material. Plus, this method allows the construction of complex geometries.
However, DMLS printers and materials are incredibly expensive. DMLS-printed parts are porous compared to parts that are made of melted metals. In addition, most DMLS printers have small build volumes compared to other types of 3D printers.
This is a powerful 3D printing technology that is ideal for creating highly detailed, realistic prototypes in a matter of hours. It utilizes photopolymer resin and UV light to build 3D objects.
How does it work? Photopolymer resin is poured into the material container and heated to achieve the desired viscosity. The printer heads then move across the build platform jetting droplets of the material. Immediately after jetting the material, the droplets are cured using UV lights, making them solid.
The printer typically features multiple printer heads, allowing different 3D printing materials to be used at the same time. For example, the support structures can be made of glycerin, quite different from the main material. This allows manufacturers to save both time and money. Polyjet technology also allows for the creation of objects with complex geometries.
This additive manufacturing method is used in a variety of industries for rapid prototyping. It is also used in the dental industry to quickly produce accurate 3D printing molds of patients’ mouths.