More large-scale additive machines are on the way. Ingersoll is working with ORNL to develop its Wide and High Area Manufacturing machine (WHAM) that has a print envelope of 46 x 23 x 10 feet. Meanwhile, Magnum Venus Products (MVP) is partnering with ORNL to develop an 8 x 16 x 4-foot thermoset printer, while several other companies, including Thermwood and Stratasys, are developing new large-scale printers.
Materials for additive manufacturing also are developing rapidly. In the same year that the BAAM premiered, Sabic released ULTEM™ – the first 3D printable, high-temperature material (350 F/183 C) developed in collaboration with ORNL and Stratasys. Other high-temperature materials and processes are also on the fast track to development. ORNL recently collaborated with Techmer PM to develop high-temperature thermoplastic materials and demonstrated fabrication of molds with six industry partners. Meanwhile, Polynt and Dixie Chemical are working with ORNL to create printable thermoset materials for MVP’s printer.
Moreover, large-scale additive manufacturing is no longer the exclusive territory of companies that can afford to purchase the equipment. Since 2016, when Akron, Ohio-based Additive Engineering Solutions (AES) was founded as the world’s first service bureau for large-scale 3D printing, other companies can easily access the technology. With these developments and major initiatives to adopt additively manufactured tooling underway in the aerospace industry, 3D-printed tooling can simply no longer be ignored.
The 3D Printing Process
Conventional tooling is typically created using subtractive manufacturing, in which a block of material such as Invar (an alloy of iron and nickel), steel, aluminum, FRP tooling board or foam is machined into a male “plug” that is then used to create a female composite mold. In contrast, 3D-printed molds are built up by rapidly depositing or “printing” beads of thermoplastic material one layer at a time. Some common thermoplastic resins used include acrylonitrile butadiene styrene (ABS), polyphenylene sulfide (PPS) and polyetherimide (PEI).
The raw material in pellet form is heated in an extruder barrel until it reaches the consistency of toothpaste. Then, it’s extruded in a horizontal pattern (on the X, Y axis) of beads. The movement of the extruder head is controlled by “slicing” software, which translates CAD files into the printing pattern. Once a layer has cooled, the print bed moves vertically (up or down along the Z axis) and a second layer is added. The process continues, adding layer by layer. Current large-scale 3D printers can lay down approximately 60 to 80 pounds of material an hour.