Ultrasonic additive technology applications
Continuous ultrasonic welding of thermoplastic composite tape to 3D printed structures represents an entirely new field of use where we have shown that composite materials can be welded to the exterior of the printed part to provide exoskeletal structure. Agile Ultrasonics has demonstrated continuous ultrasonic additive processing that doubles the strength of 3D printed hat stiffeners. Contact us for a paper on this approach.
Based on Agile’s continuous additive welding process, exoskeletal strengthening of large-format printed structures can be rapidly modified for added strength and versatility while enabling more complex yet lightweight and multifunctional integrated units.
For example, while a large-format 3D printer produces a watercraft hull, an adjacent Agile robotic end effector can continuously ultrasonically weld composite materials to the inside and outside of the printed hull. Because the composites add structure the printed material becomes the substrate which is now strengthened, enabling the volume of printed material to be reduced. The hull thus becomes lighter and stronger. Based on advancements in polymer science, there is no limit to the number of times that 3D printed TP material can be combined with composites: 3D print, add composites, 3D print, add composites. Furthermore, the same technology can be used to weld the deck to the hull, wrap composite tape as needed, and enable continuous field repair in remote locations.
Examples of 3D Additive applications
Additive reinforcement of composite structures
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Continuous welding of composite strips to 3D printed stiffeners
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Doubling the bend strength of the parts
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Extension to interlaminar strengthening
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Lightweighting
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Complex shaping
There are several methodologies currently employed to introduce continuous fiber thermoplastic materials into the 3D extrusion printing process. Most of these processes require the presentation of fiber tows through an extrusion head or nozzle. These fiber tows may be introduced dry, and impregnated in-situ in the extrusion process, they may be pre-impregnated with a thermoplastic matrix and extruded in conjunction with additional material, or they may comprise the entirety of extrudate. These existing processes face some inherent limitations. In particular, due to the nature of the extrusion process, proper alignment and tensioning of reinforcing fibers (critical to optimizing mechanical performance) can be challenging to achieve. Additionally, throughput is limited to the volume of material that can be introduced through the extrusion head/nozzle in a given timeframe.
Our technique demonstrates a method that introduces pre-impregnated and pre-consolidated continuous fiber thermoplastic tapes and multi-axial laminates into the 3D printing process as a secondary operation. This can be performed in parallel with the extrusion printing process, allowing the selective addition of these higher strength materials where needed in a particular structure. Depending on the size and shape of the structure being printed, this methodology could be employed with little to no impact to the throughput of standard extrusion printing technology. Data collected from testing of a representative component will be presented to show the possible improvement in properties that can be achieved.