Boeing, Navy ManTech, NAVAIR AERMIP and Thermwood Collaborate on Large Scale Composite AM Cure Tool

Posted by Duane Marrett on Wed, Jun 30, 2021

Tags: Thermwood, Announcements, Large Scale, Thermwood LSAM, Navy, Composite Tooling, Boeing, Navair, Collaboration, Fleet Readiness Center

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.

Boeing, Navy ManTech, NAVAIR AERMIP and Thermwood Collaborate on Large Scale Composite AM Cure Tool

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

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

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

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

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

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.”

LSAM Info Request

Thermwood Continues Development of its Large Scale Additive Manufacturing System

Posted by Duane Marrett on Mon, Oct 19, 2015

Tags: Announcements, Additive, Large Scale, Testing

Thermwood Corporation, a major U.S. based manufacturer of CNC routers, has embarked on a program to develop Large Scale Additive Manufacturing (LSAM) which can perform both the “additive” and “subtractive” functions on the same machine. This approach, called “near net shape”, uses a high volume thermoplastic printer to quickly create a part that is nearly, but not exactly, the final net shape. A “subtractive” function then machines the part to the exact final net shape. In its final form, Thermwood’s system will perform both the “Additive” and “Subtractive” functions on the same machine.

MeltShape Technology 

Thermwood’s MeltShape wheel is servo controlled to precisely follow machine motion.
Thermwood's MeltShape wheel is servo controlled to precisely follow machine motion

Vertical wall after additive process

 

Horizontal slab during additive process

Both vertical walls and horizontal slabs were successfully built during initial testing


More complex pattern during the additive process

More complex pattern after the subtractive trimming process
A more complex pattern was also created and trimmed as part of the testing process


Thermwood’s development system has performed well during initial additive testing. It has been tested through its entire operating range. This startup effort included initial validation of an all new “MeltShape Technology”. Melt shaping promises enhanced control of layer shape and improved bonding between layers. This new patent pending approach uses one or more shaping wheels to shape, form and compress the hot plastic melt as it is being extruded, insuring that each new layer is the proper shape and thickness and that it bonds firmly to previously applied material.  Melt shaping offers a new and promising technique in the advancement of large scale additive manufacturing. 

Featuring an extruder from American Kuhne

American Kuhne

Kevin Slusarz, American Kuhne vice president of process technology, assisted with the start-up effort.  American Kuhne, a Graham Group Company, supplied the custom extrusion system for Thermwood’s development machine. The extrusion system performed flawlessly during initial testing. Extruder controls are designed to smoothly network and integrate with the machine control. “We are quite pleased to have a partner like American Kuhne as part of this development program” says Ken Susnjara, Thermwood’s CEO. 

20% Carbon Graphite Filled ABS

The material processed during startup testing was a 20% carbon graphite filled ABS from Techmer ES. Thermwood is in discussions with other material supplier to test their material in this new application. 

MeltShaping Approach 

Thermwood’s melt shaping approach to adding material offers several significant advantages. Because layers are rolled together, rather than tamped together, air between layers is squeezed out during the additive process, so it is much less likely that air becomes trapped between layers. This was borne out during initial testing which produced virtually void free walls. This addresses the problem of trapped air delaminating layers when a part is processed through a heated autoclave, which is a common requirement for aerospace parts and patterns.  

Full Six Axis Articulated Additive Deposition Head 

This approach uses a melt shaping wheel that interact with the extruded thermoplastic bead while it is still hot and pliable. The shaping wheel is servo controlled so it can track the direction of machine motion. The Thermwood machine is a full six axis system, five axes to position the head in any orientation and the sixth axis to align the shaping wheels to the machine motion direction. Thermwood has added a software feature to its Q Core CNC control called “Tangential Following” which automatically keeps the shaping wheel aligned with the direction of machine motion without the need for six axis programming. This eliminates the need for a specialized CAD/CAM system to handle the sixth axis and allows the use of virtually any five-axis CAD/CAM system to program machine motion. 

Multiple Shaping Modules

Thermwood envisions different shaping wheels, each imparting specific characteristics to the hot plastic bead. 

Further Details

Because of its five axis head configuration, material can be applied at an angle or onto a curved surfaces in addition to traditional horizontal layers. This capability opens new processing possibilities and supports free form additive manufacturing techniques not currently possible. 

Thermwood’s initial test machine, which can print parts up to ten foot by ten foot by five foot thick, is expected to be fitted with a five axis “subtractive” gantry trim system in the next few months at which time all functions can be performed on the same machine. 

Ongoing Development

Thermwood Additive Manufacturing System
Thermwood’s LASM development machine can print parts up to ten foot by ten foot by five foot high

Thermwood plans to continue this development effort with the goal of offering these machines in a variety of large sizes for commercial applications. Management cannot yet determine when the technology might be sufficiently refined for commercial rather than purely research and development applications. In the meantime Thermwood plans to continue working with material vendors, R&D operations and potential users in an ongoing development effort.