By Olivia Cahoon
Part 2 of 4
While plastic is often used to create functional three-dimensional (3D) objects, some users opt for a modern twist and select chemically bonded composite materials. These 3D printing materials are available in several variations including wood, metal, and sandstone.
A variety of metals may be 3D printed including aluminum, bronze, cobalt, copper, gold, iron, nickel, platinum, stainless steel, steel, and titanium combined with polylactic acid (PLA). Metals are printed directly by binding metal dust and firing until hardening. Finished objects may be electropolished or machined to finish into functional metal parts.
Typically, metal 3D materials are created with a variety of metal compositions to achieve a specific aesthetic or function. Some metal materials like steel offer special finishes like matte or polished in stainless, bronze, gray, and gold.
Metal 3D printed objects include custom items, functional parts, jewelry, medical devices, prototypes, and small structures. Because of its strength and durability, metal is also used in industrial applications for aircraft frames, jet engines, magnetic pieces, manufacturing, oil and gas equipment, nuclear components, power generation, and refractory metal components.
Sandstone is used as a 3D printing material for architecture, figurines, fine arts, memorabilia, and presentation models. Delicate, it is suited for projects with little to no handling. To 3D print with sandstone, a binding agent is applied by layer to sandstone powder until the powder is solidified into a sandstone-like material. Color jets inject color onto the 3D printed object as the binding agent is applied.
Because it is brittle, sandstone material doesn’t allow protruding features smaller than three millimeters and walls must be wider than two millimeters. To save on costs, most users hollow 3D models and add holes for the excess sandstone powder to escape.
Sandstone is not recyclable, watertight, or safe for contact with food. Finished 3D objects may be embossed or engraved.
Wood-based 3D printing materials are produced by fused deposition modeling. The material contains a mixture of recycled wood with binding polymer to create objects that resemble wood. Using wood materials in a 3D printer is similar to plastic filaments.
3D printed wood objects can be drilled, nailed, painted, sanded, and stained. Common 3D printed wood objects include boxes, chairs, cups, décor, figurines, and tables.
Wood material is typically weaker and softer than polylactic acid or PLA. It also has reduced flexibility and breaks easily. Print temperatures for wood materials range between 195 to 220 degrees Celsius with higher temperatures yielding darker brown shades.
Other 3D printing materials include new, innovative solutions like beer, coffee, and hemp. As the 3D printing market expands, new materials emerge for a variety of uses. The next part in this four-article series examines the evolution of 3D printing materials.
May2018, Industrial Print Magazine