A Polysulfone (PSU) mold, claimed to be the world’s first, has been successfully 3D printed and used to produce an oil drip pan for a Chinook, Boeing Vertol’s twin engine helicopter.
The mold was created in a collaboration between Thermwood Corporation, Techmer PM, and Purdue University’s Composites Manufacturing and Simulation Center. The final component was then produced in an autoclave by Applied Composite Engineering (ACE).
Making the component
The mold for the oil drip pan was 3D printed and trimmed using Thermwood’s LSAM machine using carbon fiber reinforced material supplied by Techmer.
The significance of 3D printing PSU lies in the properties of the material. PSU requires significantly higher higher temperatures and higher torque (rotational force) in order to be processed successfully. The LSAM print head, as previously reported by 3D Printing Industry, has an extruder head that can complete this.
LSAM was able to produce a mold that was “void free and able to sustain vacuum without secondary coatings.” Additionally PSU has a Tg (glass transition temperature) of 189 degrees Celsius, allowing the the drip tray to be molded with the tool in an autoclave at 135 degrees Celsius at just over 600,000 Pascals.
Engineering efficient times, engineering efficient costs
By 3D printing the mold, 34% of the total material cost was saved, and labor hours were reduced by 69%, including a build time slashed from 8 days to 3 days.
Increasing the size of the drip pan mold would also not require any additional support structures to be built.
The team states that the next stage is to investigate how another polymer, Polyethersulfone (PES) might be used in 3D printing. PES, according to the project, “processes and operates at even higher temperatures” than PSU.
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Featured image shows the final drip tray, molded using a 3D printed PSU mold. Photo via Thermwood.