Table 1.

A brief overview of 3D printing methods

Starting material		Method	Layer thickness (µm)	Method overview	Advantages	Disadvantages	Example of use in Ecology and Evolution
Solid	Plastic filament	Fused Filament Deposition (FFD)	300–1,000	Plastic filament is melted and placed in layers by the print head	Common plastics, such as ABS, can be used. Chemical properties retained	Anisotropic (strength differs in Z‐axis, to X‐Y axis). Stepped surface, which lacks fine details	Thermal ecology model lizards (Watson & Francis, 2015)
Powder	Metal	Laser melting	20–100	Thin layers of powder are spread over a bed which the laser selectively melts. Once solidified, a new layer of powder is spread	>99% of the metal's density can be achieved, therefore good mechanical properties	Expensive and slow, limited metals can be used, it is not suitable for reactive metals
		Electron beam	0.3–100	Powdered metals are selectively melted by electron beam in a vacuum	As for Laser melting. Reactive metals (e.g., Titanium) can be used	Expensive, slow and limited metals can be used
	Plastic Metal	Laser sintering	100–300	The laser selectively melts powdered plastics and the model is made in the powder bed	Common plastics can be used. Cheap for small number of objects. Chemical properties of material are retained	Poor surface finishes and tolerances are limited	Ceramic filter holder (Lücking et al., 2015)
	Any powder	Binder jetting	90–200	Powdered material is placed in layers over the build area and then glued together with a binding agent	Any powdered material can be used. Relatively fast and cheap. Color models are possible	Produces fragile parts which need further treatment. Poor surface finish
Liquid	Photo‐polymer	Stereolithography (SLA)	16–150	A laser selectively solidifies thin layers of photopolymer. The print bed moves down to allow a new layer of polymer to form	Accurate with good surface finish that can capture fine details	Expensive and photopolymers are not stable long‐term	Model Neotropical bush‐cricket (Jonsson et al., 2017)
		Photopolymer jetting	16–500	Thin layers of photopolymer are jetted on to the build area. They are cured with ultraviolet light straight away	Multiple materials can be used. Can be high precision	Expensive and photopolymers are not stable long‐term	Models of black widow spiders (Brandley et al., 2016) Mold for microfluidic devices (Kamei et al., 2015)
	Wax	Material jetting	13–50	Inkjet printer heads drop hot wax on a bed, which cools and forms layers	Accurate with good surface finish. Suitable for lost wax casting	Slow process that produces fragile models	Replicating delicate dinosaur bones (Bristowe et al., 2004)

Examples, from papers cited in the main text are provided to illustrate applications. Layer thicknesses are approximate as specific makes and models of 3D printers will vary. A guide of prices for different technology types can be found in Table 2