The top processes in Additive Manufacturing (AM) can be generally categorized as filament-based, resin-based, or powder-based. While there are some variations in these processes, the vast majority of materials fall within these three categories. Additive Manufacturing has a wide range of materials that fit many different applications and industries. From aerospace, engineering, automotive, medical, and so many more, looking at different properties can help you decide what material is best for you and your specific needs
1. Fused Filament Fabrication (FFF)
Filament-based materials are typically housed in a spool format. Filaments are commonly found in two diameters: 1.75mm and 3mm with the former being the most common. By far the largest variety of materials for AM are available as filament. The most common include:
- By far the most common material for filament-based printing. It is also available in a wide range of composite variations including carbon fiber and glass filled.
- This is a type of polyester made from fermented plant starch. As it is plant-based it is considered one of the most environmentally friendly plastics available.
- Very easy to print on most 3D printers. It prints at a relatively low temperature and is less prone to warping than other materials.
- Printed parts are dimensionally stable and more rigid than other polymers like ABS. Some PLA variations can also be annealed for greater strength.
- Offers a low-cost option for prototyping.
- Offers properties similar to ABS in terms of durability.
- It is not as easy to print with PLA as parts can shrink and curl off the print bed. Requires higher temperatures than PLA.
- Also available as a composite with other materials such as carbon fiber and glass-filled.
- PETG is fully recyclable and considered environmentally friendly.
- Great for prototyping parts that require chemical resistance and durability.
- Strong and durable with high-impact resistance.
- Popular for prototyping injection molded parts that will ultimately use ABS in production.
- It can be tricky to print with these materials on printers that do not have a heated chamber.
- Not as environmentally friendly as other materials, but can be recycled.
Filament-based materials are also available in some interesting variations including:
- ASA – (Acrylonitrile styrene acrylate)
- Igus Iglide
- a slippery material used for bearings
- BASF Ultrafuse 316L
- stainless steel powder in a binder that can be used to print metal parts
- PEI (Polyetherimides)ULTEM
- PAEK (Polyaryletherketone) family of polymers
- PEEK and PEKK (and other variations)
PEI and PAEK materials have exceptional thermal and mechanical properties making them ideal for aerospace and medical applications. They require very high temperatures in an enclosed environment in order to print well. They are also available as composites with carbon fiber and glass fiber.
2. Powder-Based Materials
These materials are available in fine powder. The powder is used in processes such as SLS (Selective Laser Sintering), MJF (Multi Jet Fusion), DMLS (Direct Metal Laser Sintering), and Binder Jetting.
The most common powder-based materials include:
- Nylon materials offer a wide range of characteristics, however, in 3D printing, the most commonly produce rigid parts in the form of PA12 and PA11.
- Excellent durability and chemical resistant.
- Perfect for prototyping parts that may ultimately be molded from the same material.
- With finishing, this material can produce injection-molded like quality for end-use parts.
- Lightweight, ductile, and chemically resistant.
- The only powder-based material that is watertight.
- It can be spin-welded.
- Uses DMLS to melt the powder into shape.
- A wide range of metal powders are available including Aluminum, Copper, Stainless Steel, and Titanium.
3. Vat Photopolymerisation Materials
These materials use a photoreactive resin that solidifies when exposed to a particular wavelength of light. The most common processes include SLA (Stereo Lithographic Apparatus), MSLA (Masked SLA), and DLP (Digital Light Processing). One of the challenging aspects of these resin-based processes is the classification of materials. Unlike filament and powder, resins derive their properties from chemical reactions that do not rely on heat. As a result, resin materials are generally classified based on the physical characteristics of their final (cured) state.
Elastomeric
- Parts with varying degrees of elasticity range in durometers as low as 40A.
- Behaviors similar to silicone.
- Some manufacturers offer pure silicone resins.
- Parts that are optically clear can be used in applications that require transparency including lenses
- Exhibits similar qualities to polypropylene.
- Dimensionally stable and rigid parts.
- In some cases glass filled.
- Often used for prototype mold tooling.
- Often equated with ABS.
- It can be used for end-use parts
For those who have worked with 3D printers in the early days of 3D printing over 30 years ago, their first exposure to 3D printed parts was likely a photopolymer part. In those days, the parts were extremely brittle and could barely be used for more than a visual representation of a part. Over the last few years, that has changed dramatically. Resin-based parts can hold their own when compared to other AM processes.
The amount of materials available for Additive Manufacturing is enormous and covers a wide gamut of performance, aesthetics, and practicality. That said, there is a narrow band of materials that are most popular. Manufacturers of these materials encourage AM users to explore beyond this narrow selection in an effort to promote end-use adoption of AM as a viable production solution. There are many cases where 3D-printed parts have matched (or even exceeded) the performance of parts produced using injection molding or machining. By selecting a material that can be used for both prototyping and end-use, the development and production processes can be seamless.
