Thermwood was a key development partner in a Navy ManTech funded program issued to Boeing Research and Technology. The ManTech program was managed by Advanced Technology International (ATI) for the Office of Naval Research (ONR) with funding provided from the Naval Air Systems Command (NAVAIR) Aircraft Equipment Reliability & Maintainability Improvement Program (AERMIP). Fleet Readiness Center East (FRCE) was a key technical contributor for the low cost composite cure tooling technology development.

The Details

Thermwood’s Large Scale Additive Manufacturing (LSAM) machine was selected as the Large Format Additive Manufacturing (LFAM) machine to conduct the technology development. Several unique equipment features of the LSAM machine drove the selection. The high temperature autoclave cure tooling operating environment of 355 degree Fahrenheit and 85 psi provides a challenge for polymer based tool material. Additional composite cure tooling requirements for vacuum integrity and dimensional stability were validated during the development. Neil Graf Office of Naval Research, noted “Composite manufacturing is a strategic technology for future platforms and development of more cost effective tooling solutions would significantly benefit the implementation.”

The Process

FRCE provided a high contour mold line surface to Boeing for generating the composite cure tool. The mold line shape was very aggressive and would stretch the large format additive manufacturing technology processes capability. The spherically shaped portion of the mold line offered the largest challenge, as the unsupported 3D printed angle limitation of approximately 45 degrees provides an interesting obstacle to overcome for the spherical mold line section of the tool. Boeing rotated the 3D print plane 35 degrees to avoid encroachment of the build angle limitation.

Final 3D Print Model

The new innovative build plane approach eliminated the requirement for temporary support material for the aggressive mold line shape. The new build angle would test the LSAM machine limits in an area never explored previously. TechmerPM PESU CF 1810 high temperature print material was used for the composite cure tool. High temperature materials present additional challenges during print over low temperature materials such as ABS CF. Two interim support features were added to compensate for the center of gravity shift of the print. The LSAM machine performed flawlessly during the composite cure tool print. The tool was printed in 7 hours and 26 minutes using 610 lbs of material.

Composite Cure Tool printing on Thermwood LSAM

The composite cure tool was machined in 53 hours using the LSAM gantry router machine. The tool datum features, and removal of interim members, were machined prior to removal from the bead-board. The Thermwood LSAM machine offers the ability to machine and 3D print on a single platform. The composite cure tool mold line part surface achieved at surface profile tolerance of .020” (+/-.010”).

Machining the Composite Cure Tool on Thermwood LSAM

The Boeing Research and Technology (BR&T) laboratory performed functional testing on the LFAM composite cure tool to ensure vacuum integrity and dimensional stability requirements were reached. The LFAM tool performed as expected and achieved all requirements. Several composite parts were fabricated from the tool. The tool durability was assessed during the multiple autoclave cure cycles and fabricated (3) composite parts. The tool maintained dimensional stability and vacuum integrity throughout the functional testing and composite part manufacturing.

LFAM tool after Autoclave Cure

The composite cure tool was printed and NC machined on Thermwood’s Large Scale Additive Manufacturing (LSAM) 1020 machine. The LFAM technology cost savings was estimated at 50% compared to traditional tool fabrication methods, and reduced tool fabrication lead-time by 65%. The cost savings and tool fabrication cycle time reduction could provide enormous benefit to any organizations performing low volume or custom composite part fabrication and repair.

Composite part fabricated from LFAM tool

Nondestructive Inspection (NDI) was performed on the composite parts fabricated on LSAM tools. The NDI results did not indicate any porosity. Due to the complex shape of the composite demonstration part several NDI process were employed. X-ray and C-Scan results did not reveal any delaminations or defects.

The Bottom Line

The program benefited from a cooperative effort among several contributors to achieve success. The partnership between industrial technology leaders, Boeing and Thermwood coupled with the Office of Naval Research’s drive to transition technology, led to the successful program. “Collaborations such as this help expand the scope of capabilities of emerging large scale additive technology by addressing real world challenges that would be difficult for any single entity to define and address by itself. We look forward to new challenges moving forward”, says Thermwood CEO, Ken Susnjara.

Additional development is key to expand LFAM composite cure tooling implementation. Boeing Associate Technical Fellow Michael Matlack commented “The program provided significant results in validating additive manufacturing as a viable method of producing lower cost, capable tooling with substantial time savings over traditional methods.”

Thermwood Corporation has entered into a collaborative program with the Naval Surface Warfare Center, Carderock Division to explore the use of additive manufacturing technology in developing marine models for ship and ship systems testing.

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The Details

Carderock Division is the U.S. Navy's state-of-the-art research, engineering, modeling and test center for ships and ship systems. It is the largest, most comprehensive establishment of its kind in the world, serving a dual role in support of both our U.S. naval forces and the maritime industry. 

Navy and maritime communities have come to depend on their expertise and innovative spirit in developing advanced platforms and systems, enhancing naval performance, reducing operating costs and addressing the Navy's evolving mission.    

This initial validation program was centered on printing an unclassified scale nose of a submarine using Thermwood’s LSAM additive manufacturing system. The part was printed using 20% carbon fiber filled ABS in 11 hours and 45 minutes using traditional horizontal layer printing and a 40mm melt core. Final trim required 5 hours. Both printing and trimming were completed on the same machine, using Thermwood’s 10’ x 20’ LSAM at its demonstration lab in Southern Indiana.

Because of layer cooling requirements, the print rate for this part was less than half of the maximum rate the machine is capable of. It is expected that, moving forward, this program will include the printing of additional components using both horizontal and vertical layer printing.

More Information on LSAM

LSAM is based on exciting new technology developed from an entirely new direction.

LSAM is intended for industrial production. It is not a lab, evaluation or demonstration machine, but is instead a full-fledged industrial additive manufacturing system intended for the production of large scale components.

Much of the technology used in Thermwood's LSAM machines and print process is completely new. Thermwood has already received numerous patents on this revolutionary development and many more are in the works. Many exciting results that LSAM has already achieved are covered by non-disclosure agreements and must be kept secret.  LSAM is truly state-of-the-art in the exciting new world of large scale additive manufacturing.

The Secret to LSAM Print Quality...A Different Process

Thermwood Corporation of Dale, Indiana has signed a formal Cooperative Research and Development Agreement with Fleet Readiness Center East located at Marine Corps Air Station Cherry Point, N.C., and part of the Naval Air Systems Command, to conduct a two-year, joint technology development effort centered on Thermwood’s emerging Large Scale Additive Manufacturing (LSAM) technology.

Thermwood’s LSAM machines are large-sized industrial additive manufacturing or three-dimensional printing machines that are available in sizes up to 100 feet long. These systems use a “near-net-shape” approach for making parts in which parts are first 3D printed at high speed to a size slightly larger than needed and then trimmed to final net size and shape. Thermwood’s LSAM machine consolidates printing and machining on the same machine using dual gantries. Dual controls allow print and trim operations to be performed simultaneously, each on different ends of the table.

“We are excited to work with the FRC East and are confident that, working together, we can achieve significant advances and results,” said Thermwood Founder, CEO and Chairman Ken Susnjara. “I am confident that this program will benefit us both while further advancing the state of the art.”

Thermwood has been in a continuous research and development program developing additive manufacturing equipment and technology, and in September announced a line of large scale additive manufacturing systems called LSAM. The dual-gantry, high-wall machines are available in sizes from 10-foot-by-10-foot to 10-foot to more than 100-foot with print capability from 150 to 500 pounds per hour.

 About Thermwood Corporation:

Thermwood Corporation, located in Southern Indiana and established in 1969, offers both three & five axis CNC machining centers ideally suited for the production, fabrication & trimming of wood, plastics, non-ferrous metals, composites and other advanced materials.  Thermwood also offers a Large Scale Additive Manufacturing (LSAM) system for 3D printing reinforced thermoplastic composite materials for producing industrial tooling, molds, patterns, masters, plugs and fixtures for various industries.  Thermwood is deeply involved in CNC and Additive Manufacturing technologies and development, incorporating a high level of smart control technology in its products. 

About Fleet Readiness Center East:

For more than 60 years, the Fleet Readiness Center (FRC) East aboard MCAS Cherry Point, N.C., has played an important part in national defense.  Our workforce has earned a reputation of excellence in providing world-class maintenance, engineering and logistics support for Navy and Marine Corps aviation, as well as other armed services, federal agencies and foreign governments. Our skilled workforce uses state-of-the-art technology to ensure that FRC East is without equal in providing quality, cost-effective support. 

 

About the Thermwood LSAM