Producing composite aerospace components requires massive, expensive tools. Hoping to address those costs, the United States Air Force Research Laboratory (AFRL) Manufacturing and Industrial Technology Division (ManTech) decided to investigate large-scale, polymer-based, additively manufactured composite-cure tooling.
Boeing responded with a submission on ManTech’s Open broad-agency announcement (BAA) to evaluate the current state of additive manufacturing (AM) technology with respect to fabricating low-cost, autoclave-capable tools. The initial demo tool is for an AFRL concept aircraft fuselage skin.
Boeing contracted Thermwood to demonstrate its large-scale additive manufacturing (LSAM) machine with vertical lay print (VLP) capability. VLP AM reduces costs by increasing the size that components can be printed, reducing assembly cost for large tools.
To validate the LSAM VLP process using high-temperature autoclave-capable materials, Boeing and AFRL chose to 3D print a section of the large tool. The mid-scale tool was printed on Thermwood’s LSAM AM demonstration machine in Indiana using a 40mm print core running 25% carbon fiber-reinforced polyethersulfone (PESU).
The initial test tool has the same width, height, and bead path as the final mold and incorporates all major features of the final mold – but was compressed in length to 4ft. The final tool will be more than 10ft. The mid-scale tool was the first high-temperature tool printed using the VLP system.
The mid-scale tool required 5 hours, 15 minutes to print and weighed 367 lb. After final machining, the tool passed room temperature vacuum testing and achieved dimensional surface profile tolerances.
The next step in the program is for production of a full-size 1,400 lb tool that will required 18 hours to print.
Boeing and the Air Force are carefully documenting all operational parameters with hopes of transitioning the technology to production programs. AM autoclave tooling offers significant advantages over traditional production methods – primarily lower cost and fabrication in days or weeks rather than months.
AFRL is very interested in tooling approaches for the Low-Cost Attritable Technology (LCAAT) program, which targets breaking the cost growth curve to field new systems faster.
AFRL Program Manager Andrea Helbach says, “We are interested in additively manufactured tooling’s ability to reduce the cost and time to procure autoclave-capable tooling. Additionally, AM tooling supports changes in vehicle design with minimal non-recurring expenses.”
“Future fielded low-cost, but capable unmanned aerial vehicles (UAVs) will need a responsive materials and manufacturing processes strategy,” says Craig Neslen, LCAAT initiative manufacturing lead. “Additive manufactured composite tooling is one of many technologies being evaluated to ensure the industrial base can handle future manufacturing surge requirements as well as accommodate periodic system tech refresh activities which could necessitate minor vehicle design changes at an acceptable cost.”
United States Air Force Research Laboratory (AFRL) Manufacturing and Industrial Technology Division (ManTech) https://www.dodmantech.com/ ManTechPrograms/AirForce