Thermosets

A thermoset is a material that strengthens when heated but cannot be remolded or heated after the initial forming. This differs from thermoplastics, which can be reheated, remolded, and cooled as necessary without causing any major chemical changes.

As implied by their name, thermoset components become set in their physical and chemical properties after initial heat treatment and are, therefore, no longer affected by additional heat exposure. After initial heat forming, the thermoset material’s resistance to heat, corrosion, and mechanical creep makes it suitable for use in components requiring tight tolerances and excellent strength-to-weight characteristics while exposed to elevated temperatures. As such, thermosets have enormous potential and very broad adoption.

The most common thermoset materials used in 3D printing include silicone, polyurethane and epoxy, which are also generally among the most widely used thermoset materials. Due to their high viscosity, printing thermosets such as polyurethane and silicone are difficult to print with extrusion technologies. Extrusion technologies with high precision are possible but also very challenging and require extensive manipulation of material chemistry and hardware system mechanics. Epoxy resins are also used for 3D printing continuous fiber parts via robotic extrusion systems. However, this approach remains largely experimental today.

Printing thermosets such as polyurethane and epoxy by combining them with photopolymers in stereolithographic technologies, as in high-speed photopolymerization processes (such as DLS and cDLM), requires more extensive chemical manipulation of the materials and system mechanics. However, this area of 3D printing is covered in photopolymer 3D printing.