3D printing is revolutionising manufacturing, enabling the production of complex components with a high degree of customisation and precision. One of the questions designers, engineers and enthusiasts ask most often concerns the strongest material available for 3D printing. There is no single answer, as strength depends heavily on the specific application, the printing technology employed and the environmental conditions in which the part will be used.
First, we need to define what we mean by “strength”. In technical terms, it is generally assessed via several mechanical properties, including tensile strength, impact resistance, temperature resistance and fatigue resistance.
In filament (FDM) printing, the most robust materials belong to the family of high-performance engineering polymers, such as PEEK (Polyether Ether Ketone). PEEK is regarded as one of the most durable thermoplastics in the world, boasting a tensile strength above 100 MPa, continuous-use temperatures up to 250 °C, excellent chemical resistance, and outstanding wear and abrasion properties. These characteristics make it ideal for extreme applications such as aerospace, automotive, medical and petrochemical components. Printing PEEK, however, requires advanced machines capable of very high nozzle temperatures and heated build chambers to maintain dimensional stability and optimal mechanical properties.
A more accessible alternative to PEEK is PEI (Polyetherimide), commercially known as ULTEM. ULTEM offers similar mechanical performance, with tensile strength approaching 100 MPa and service temperatures of around 170 °C. Its chief advantage is compliance with stringent fire-safety standards (UL94 V-0), making it popular in the aerospace and electronics sectors.
Another high-performance option is PPS GF (Polyphenylene Sulphide glass-filled), a thermoplastic reinforced with glass fibres that reaches very high tensile strength (≈126 MPa) and exceptional stiffness (elastic modulus up to 11 GPa). PPS GF stands out for its excellent chemical and thermal resistance, with continuous-use temperatures up to 220 °C, making it perfect for chemically aggressive and high-temperature industrial environments—automotive parts, electrical components, valves and advanced structural elements. Do bear in mind, however, that the glass fibres make it brittle under direct impact.
Carbon-fibre-reinforced nylon (PA12 CF) is also widely used in FDM, offering good tensile strength (≈56 MPa) and remarkably high stiffness (elastic modulus up to 8.3 GPa), ideal for structural parts in the automotive and aerospace industries.
Within HP Multi Jet Fusion technology, nylon (polyamide) remains the most versatile and resilient material. Specifically, PA12 is a mainstay thanks to its tensile strength of roughly 48 MPa, high toughness and excellent dimensional stability, making it suitable for functional parts like fittings, gears and casings for industrial devices.
Another MJF material is polypropylene (PP), valued for its exceptional chemical resistance, lightness and flexibility. PP exhibits tensile strength of about 30 MPa, with significant elongation at break (≈20 %), allowing it to withstand repeated flexing and impacts without permanent deformation. It is the material of choice for living hinges, functional housings, automotive components and containers exposed to aggressive chemicals or humid environments, thanks to its low moisture absorption.
Turning to stereolithography, the strongest options are engineering resins. ‘Tough’ resins, such as ABS-like formulations, deliver solid mechanical strength (40–45 MPa) and moderate elasticity, enabling parts to survive minor impacts and deformations—ideal for functional prototypes and components that must bear moderate loads.
High-temperature resins offer very high thermal resistance (up to 260–285 °C) coupled with high stiffness and mechanical strength (≈60–70 MPa). However, they are extremely brittle under direct impact, limiting their use to parts under mainly static loads and thermally extreme environments, such as thermoforming moulds and laboratory components.
Lastly, certain PP-like resins combine moderate mechanical strength (≈30–34 MPa) with very high ductility and impact absorption, making them perfect for flexible hinges, clips and casings subject to frequent stress.
In conclusion, there is no single “strongest material” in 3D printing. Each technology offers top-tier materials with distinct characteristics that must be selected according to the specific application. For structural parts in extreme environments (high temperature, continuous chemical or mechanical stress), materials such as PEEK, ULTEM and fibre-reinforced nylons are unbeatable. For applications that demand dimensional accuracy and moderate elasticity, tough resins are the best choice. Optimal material selection therefore requires a careful, comprehensive assessment of your particular requirements, ensuring maximum effectiveness and longevity of the 3D-printed component.