Initially, 3D printing focused on polymers for printing objects due to the ease of producing and handling polymeric materials. In the past two decades, the technique has significantly evolved to print not only different kinds of polymers but also ceramics and metals.
This has made 3D printing technology more versatile and cost-efficient than ever before. Since more companies are buying additive manufacturing hardware, the market for 3D printing materials is growing rapidly.
According to the Markets&Markets report, the size of the 3D printing material market is expected to increase from $1.6 billion in 2020 to $4.5 billion by 2025, at a compound annual growth rate of over 23%. This growth is further fueled by the rise in demand from automotive, aerospace, healthcare, and other industries, globally.
With such an incredible opportunity at hand, giant metal producers, chemical companies, and materials suppliers are becoming increasingly involved in the industry. In addition to making new materials 3D printable, several companies and organizations are contributing heavily to the industrialization of additive manufacturing.
Below, we have listed all crucial 3D printing materials (along with their properties and benefits) suitable for various types of 3D printers.
6. Carbon Fiber
Object made of PETG (80%) and carbon fibers (20%)
Applications: Lightweight props, functional prototypes
In the 3D printing industry, carbon fiber, fiberglass, and Kevlar are the three most common fiber materials used as composites. They are infused into a base material to enhance the properties of that material.
Carbon fiber, in particular, has a high strength-to-weight ratio, which makes it an ideal candidate for creating lightweight yet strong components. The fibers contain carbon atoms whose crystal structure is aligned into strands, making strands excessively strong in tension. These fibers have two variations:
Chopped fibers: are short-length fibers cut into multiple parts. Each part is less than one millimeter long and merged into conventional thermoplastics to form the desired material. This material is used in FDM (Fused Deposition Modeling) printing process.
Continuous fibers: work with printers that have two print nozzles. One nozzle lays down a base material (such as a plastic filament) to form the internal matrix and outer shell of the part, while the second nozzle deposits a continuous strand of carbon fiber on every layer. These continuous strands add strength to the printed object that is comparable to components made by 3D metal printing.
Graphene, dubbed as a ‘wonder material,’ is a single layer of carbon atoms arranged in a honeycomb-like structure. This unique arrangement of atoms gives graphene its immense array of unique properties like extraordinary flexibility, conductivity, and transparency.
Like carbon fibers, graphene is infused into a base material (such as plastics) to enhance the properties of that material. Graphene nanoplatelets make materials mechanically stronger while improving their electrical and thermal conductivity.
It works with various additive manufacturing techniques, including FDM, selective laser sintering (SLS), stereolithography (SLA), and direct ink writing (DIW). Graphene-based 3D prints possess promising applications in a wide range of fields, from electronics to biomedical aids.
Pieces made of transparent resins
Applications: Medical devices, electronic components, Intricate parts, jewelry
Resins are a group of photopolymers that contain a photoinitiator and several monomers. These materials react under ultraviolet light or laser beam energy, changing their state from a (highly viscous) liquid to a solid structure.
Stereolithography (SLA) 3D printing uses an ultraviolet laser to cure liquid resin into a hardened object in a process known as photopolymerization. The 3D printer directs the laser to certain regions that need to be solidified and creates the model layer-by-layer.
Different combinations of the photoinitiators, monomers, oligomers, and various additives result in different material properties. Generally, SLA 3D printing produces precise and highly detailed parts with impressive surface finishes. It is being used in a broad range of applications because there is a wide variety of resins available in the market.
Standard resins: produce translucent objects with a yellowish or greenish color. They provide a high level of detail and great surface quality at a low cost. The prints can be easily painted and post-processed.
High-detail resins: use PolyJet 3D printing, in which the printer jets an ultra-thin layer of resin (up to 32 µm) onto a building platform and hardens the layer using ultraviolet light. The process is continued layer by layer until the complete object is printed. It produces small, opaque models with fine details.
Transparent resins: produce transparent objects with a slight blue tinge. The more the thickness of the object, the more noticeable the bluish tinge becomes. It is ideal for printing visual, water-resistant models with limited functionality, such as rings and chess pieces.
Some machines use powdered materials to create 3D objects. They are called powder 3D printers. The two most popular powder printing processes are powder bed fusion and binder jetting.
The former involves sintering of melting powder particles with a laser into the desired product layer-by-layer while recoating blade of the printer adds more powder for every new layer.
The binder jet printer, on the other hand, uses a print head to deposit a liquid bonding agent, which binds powder particles together to create each layer of the product.
The powders that work with such 3D printers come from many different source and materials, but the most common are:
Applications: moving and interlocking parts
Polyamide prints are made from a white, very fine, granular powder. This powder-based material gives you the flexibility to construct complex designs.
Also known as nylon, polyamide tough, abrasion-resistant, and possesses higher strength and durability than most thermoplastics. It can be reinforced with glass fiber or carbon fiber to enhance its mechanical properties.
Since polyamide offers a great rigidity to flexibility ratio, you can 3D print objects like living hinges with rigid parts and flexible joints. The printed objects usually have a good surface finish and require less post-processing.
Applications: Casings, gadgets, jewelry
Alumide contains nylon filled with aluminum dust. It is no more or less durable than polyamide. However, it can withstand relatively greater thermal loads, maintaining its shape at higher temperatures.
Alumide is used with Selective Laser Sintering (SLS) technology to print objects with a metallic appearance. The design specification of the material makes it possible to print complex and enclosed volumes.
You can use alumide for both rapid prototyping and production, especially for mechanical parts that are subjected to low stresses or ornamental objects that require a metallic appearance. Although it is water-resistant, alumide prints must not stay in contact with water for extended periods of time.
Metal 3D printing is used through a process called Direct Metal Laser Sintering (DMLS). It involves using a high-power, computer-controlled laser beam to melt and fuse layers of metallic powder together.
This industrial process prints complex, one-piece metal objects with geometries that are extremely difficult to machine.
The popularity and growth of metal in the 3D printing industry have the potential to manufacture more effective machine parts that currently cannot be built onsite. So far, various metals have been proven useful in producing fully functional prototypes.
2a) Stainless Steel
Applications: Utensils, cookware, and complex, water-resistant parts
Stainless steel is distinguished for high ductility and strong resistance against corrosion. Without any specific finishing, it gives off a granular and coarse appearance. Stainless steel 3D prints can be welded, drilled, machined, granulated, electro-eroded, polished, and coated.
These characteristics make it an ideal candidate for implementation in numerous industries, such as the automobile industry for producing corrosion-resistant parts, the aerospace industry for mechanical parts, and the medical field for surgical assistance, endoscopic surgery, or orthopedics.
The two most popular examples of 3D printed stainless steels are the heat treatable 17-4 PH and the extremely corrosion-resistant 316L stainless steel. The latter is created from fine metallic powder primarily composed of iron, enriched with chrome, nickel, and molybdenum. They provide the smoothest prints compared to other metal 3D printing materials.
Applications: Heat exchanger, ductworks, engine parts
Models printed in aluminum are very strong, accurate and can handle details of up to 250 micrometers. They look slightly different from conventional shiny, milled aluminum — they are a little bit grayer and more matte.
Various aluminum alloys are used in metal 3D printing. Objects printed with AlSi7Mg0.6, for example, have good mechanical properties can be subjected to high voltages. These lightweight and durable prints are made of aluminum (90%), silicon (7%), and magnesium (less than 1%).
The composition makes this alloy very suitable for molding. Thus, it is mostly used in foundries for detailed objects and intricate geometries.
Applications: Jet engines, airframe components, medical implants
Titanium’s high strength-to-density ratio, good chemical and corrosion resistance make it a perfect candidate for high-performance industries such as aerospace and defense. And since it is biocompatible, it is particularly desirable for medical applications like implants.
Selective Laser Melting (SLM), Electron Beam Melting (EBM), and Direct Energy Deposition (DED) are the three most common 3D printing techniques used to produce titanium parts. They mostly use Titanium 64 (Ti-6Al-4V) — the widest-known titanium alloy that combines incredible mechanical characteristics with low specific weight.
While titanium has numerous advantages, it remains a relatively expensive metal. This is because it is mined in relatively small quantities, and processing raw titanium involves complex procedures.
Plastic is the most common and the most diverse 3D printing material. Its flexibility, smoothness, fitness, affordability, and wide range of color options make it superior to other materials.
Plastic filaments are sold on spools with either a shiny or matte texture. They are mostly used in FDM (Fused Deposition Modeling) printers. The printer melts the thermoplastic filament and molds it into shape, layer by layer.
Today, we use many different types of filaments to 3D print plastic products. The most common ones are:
Object printed with wood-based PLA filament | Image credit: Flickr
Applications: Decorative parts, cosplay props, dimensionally precise assemblies
PLA (short for polylactic acid) is a thermoplastic aliphatic polyester, most commonly used as a feedstock material in desktop 3D printers. It’s a biodegradable polymer containing renewable raw materials.
Since PLA isn’t a good heat-resistant material, it is specifically used to print decorable objects with no mechanical constraints. However, it’s a go-to material for most users due to its low cost and ease of use.
In the past decade, many variations of PLA filaments have been produced, including PLA made with wood fibers, aluminum PLA, and PLA with bronze particles. It turns out that the possibilities offered by PLA are endless.
Legos made with ABS
Applications: Automotive hardware, toys, or action figures
Created from Acrylonitrile, Butadiene, and Styrene polymers, ABS is commonly used in household 3D printing. Unlike PLA, ABS plastic sheets are not biodegradable. However, it is biocompatible and recyclable.
The material is known for its strength and impact resistance. With ABS, you can print durable objects that can hold up to prolonged usage and wear. They can also withstand relatively higher temperatures before they start to deform.
ABS prints lend themselves well to numerous post-processing techniques. Sanding, milling, cutting, drilling, gluing, and painting (with acrylic paints) — all of these steps can be performed on ABS parts.
Polycarbonate filament and 3D printed object
Applications: Engineering parts, DVDs, electronic cases
Polycarbonate (PC) is a transparent amorphous thermoplastic, primarily known for its incredible strength, impact resistance, and extremely high heat deflection. It can withstand torsional stress and tensile forces that deform or shatter other materials like ABS and PLA.
PC prints can maintain their structural integrity up to 150°C. They are also quite flexible, which means they can be bent (not too much) without breaking.
Unlike ABS or PLA, Polycarbonate can be reinforced with carbon or glass fibers to enhance its strength while making it lighter. Some PC filaments consist of additives that allow them to be printed at lower temperatures.
Polycarbonate works best with FDM printers that can handle high extruder temperatures and have an enclosed build volume.
3D printed model before and after removing PVA
Applications: Removable supports or rafts, decorative parts
Polyvinyl alcohol (PVA) is a colorless, odorless, water-soluble polymer with substantial biocompatibility characteristics. It is used as a support material for prototyping highly complex and intricate designs with large amounts of cavities and over hangings.
Generally, PVA is used on printers with dual extruders, where one extruder prints with a primary material (such as PLA or ABS) and the other prints PVA filament. Since PVA dissolves in water, the support structure printed with this material can be removed by simply emerging the part for a few hours.
PVA is also less toxic and reasonably biodegradable, so it can be used in health products such as contact lens solutions.
Image credit: Tech2C
Applications: Waterproof objects, medical braces, bottles
PETG combines the properties of Polyethylene Terephthalate (PET) and Glycol. The latter has been added to reduce the overheating issues of PET and its brittleness. More specifically, glycol is added during the polymerization process to make the materials less fragile, more durable, and easier to use.
While PETG is translucent, it also comes in a range of colors. It has impressive thermal stability, chemical resistance, and food compatibility.
PETG filaments are suitable for FDM or FFF (fused filament fabrication) 3D printers. They can be printed at speeds 40-60mm/s. However, they cannot serve as a support material because of their sticky appearance which makes them difficult to remove.
Frequently Asked Questions
What materials cannot be 3D printed?
Materials that cannot be melted into a semi-liquid state or solidified via any means aren’t suitable for 3D printing. For example, 100% wood, paper, fabrics/cloth, and most rocks earth.
What are the major technologies used in the 3D printing market?
The effective 3D printing technology currently available are:
- Fused Deposition Modeling (FDM)
- Selective Laser Sintering (SLS)
- Stereolithography (SLA)
- Direct Metal Laser Sintering (DMLS)
- Electron Beam Melting (EBM)
- Digital Light Process (DLP)
What exactly is accelerating the growth of 3D printing materials?
The benefits such as superior quality products, faster production process, and cost-effectiveness are propelling the demand for high-performance 3D printing materials globally. Much of the increased demand is coming from the automotive, aerospace, electronics, consumer products, and the healthcare industry.