After printing, 3D tooling must be machined to remove the corduroy-like scallops along its edges to create a smooth surface. The molds are then sanded (typically by hand) and sealed. Finishing is generally done on a separate machine, although the LSAM has two gantries that can be fitted with either a print extruder or routing header, making it possible to print and mill two separate parts simultaneously.
The Benefits of 3D Printing
Conventional tooling can be expensive and time consuming to produce. According to Peter Hedger Jr., director of marketing and communications at Magnum Venus Products (MVP) in Knoxville, Tenn., major aerospace companies typically create tooling by milling down a block of Inconel® (nickel chromium alloy) or Invar. “That process can cost them close to a million dollars and about six months of time,” he says. Faster, 3D-printed tooling can shave days, weeks and even months off conventional tooling lead times.
Schniepp says that Dassault Aviation in Paris, which makes Dassault Falcon business jets, realized significant time savings when it began using Stratasys 3D printers to create tooling for CFRP and GFRP cabin components. “Traditionally, they would have to machine a metal mold, tooling board or glass epoxy tool,” he explains. “Those types of processes – even for a relatively small, simple shape – take a couple of months. Now, they can have a mold in a couple of days.”
The combination of materials and production speed often also make additively manufactured tooling significantly cheaper. In 2016, Thermwood and Indianapolis-based Applied Composites Engineering (ACE) conducted an experiment to compare 3D-printed tooling to conventional methods, with each company producing a tool for a Chinook helicopter drip pan. ACE used a traditional method, cutting and machining RenShape® board to create a plug and pull a female mold off it. Thermwood used its LSAM to print the mold out of GFRP with a polysulfone (PSU) matrix. The results were striking. Jason Susnjara, vice president of marketing for Thermwood, says the additive manufacturing process reduced material costs by 34 percent, reduced labor costs by 69 percent and took three days instead of eight.
In 2016, ORNL and Boeing developed a 3D-printed drill-and-trim tool for fabricating a section of the wing of the Boeing 777x. The 1,640 pound, 17.5-foot long, 5.5-foot wide and 1.5-foot tall tool was the largest solid 3D-printed object in the world at the time. A typical trim tool of that size takes significant resources and more than six months to produce, according to Kunc. Instead, the demonstration tool was 3D printed on a BAAM in about 30 hours, finished in two weeks and cost less than $20,000.