By Cassandra Balentine
Additive manufacturing is a method of three-dimensional (3D) printing that involves adding layers on layers of material—including but not limited to plastics or metals to build an object. Building off of this concept is large scale additive manufacturing (LSAM), which is a newer technology for printing thermoplastic polymers.
Thermwood Corporation is a U.S.-based CNC machinery manufacturer. It is also an innovator in LSAM of thermoplastic composite molds, tooling, patterns, and parts. The company offers a line of LSAM machines that perform both 3D printing and trimming on the same machine. The systems are marketed to organizations in the aerospace, marine, automotive, and foundry industries as well as military, government, and defense contractors.
In a white paper on LSAM technology, published by Thermwood, the company outlines the benefits of additive manufacturing. Parts were traditionally produced by machining an oversized blank and removing material to achieve the final net shape. Near-net shape additive manufacturing—on the other hand—prints a part that is close to the final size and shape. It is then trimmed to its final dimensions. “The amount of material removed is much less, resulting in faster processing, lower cost, and more efficient use of material. It is an ideal approach for really large parts where alternative production methods may not be possible,” states the white paper.
Thermwood employed the technology to produce a large, single-piece tool for the Boeing 777X program. Boeing is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, and missiles on a worldwide basis. The project showcases LSAM’s readiness to produce production-quality tooling for engineering sensitive industries such as aerospace.
For the Boeing program, Thermwood used a LSAM machine as well as newly developed Vertical Layer Print 3D printing technology to fabricate a tool as a one-piece unit. By doing so, it eliminated the additional cost and schedule required to assemble multiple 3D printed tooling components. In the joint demonstration program, Thermwood printed and trimmed a 12-foot long research and development tool at its Southern IN location.
The tool, an aerospace trim fixture, was made up of reinforced ABS carbon fiber. The print time was 43 hours and 20 minutes while the trim time was 40 hours. The tool weighed in at 1,540 lbs.
The benefits of utilizing LSAM for the project include a time savings of weeks and enabling delivery of the tool before traditional tooling could be fabricated.
As previously noted, the Boeing program employed the use of Thermwood’s LSAM technology. The technology is a solution for large-scale 3D printing of thermoplastic polymers. According to the company, this is an alternative to other large-scale additive solutions that tend to scale up to small, filament-fed desktop printer techniques. The technology is suited for producing a variety of components, however Thermwood focuses on using the LSAM process for industrial tooling, masters, patterns, molds, and production features in a variety of industries.
Thermwood’s LSAM machines use a two-step, near-net shape production process. First, the part is 3D printed layer by layer—slightly larger than the final size. Then it is trimmed to its exact final net size and shape using a CNC router.
Thermwood’s LSAM machines utilize the company’s new Melt Core printheads. The advantages of this design, according to the company, include tighter control of print bead size, the ability to change print bead dimensions while printing, the ability to print at high output rates without surging problems, better fusion between printed layers, and a more void-free printed structure.
In Thermwood’s LSAM process, software is integral. The process starts with a 3D computer model of the part created in a CAD system. This design, in an industry standard solid, surface, or mesh file format, is loaded into Mastercam software from CNC Software, Inc. From there, Thermwood’s LSAM Print3D software utility, which operates within Mastercam, is used to generate the CNC print program needed to print the part with the print gantry. According to the company, both a working copy of Mastercam and Thermwood’s LSAM Print3D software utility are required to develop a print program. The 3D computer model is then used to generate a trim program to drive the trim gantry.
LSAM is a type of additive manufacturing 3D printing process. The latest advancements in technology by companies like Thermwood make it ideal for industrial applications in industries ranging from aerospace to automotive.
Feb2019, Industrial Print Magazine