The combination of high-speed fiber placement and low molding and consolidation times is enabling automotive manufacturers to take advantage of the benefits of composites. The highest strength-to-weight ratio available can be brought to high volume manufacturing of composite parts to reduce weight and improve performance, while new CAFE standards are easily met without significantly increasing part costs.
Highest Strength-to-Weight Ratio
The highest performance composites engage continuous fibers in pure axial tension. This is a key objective of Automated Fiber Placement (AFP). Unidirectional tape is oriented along load paths at the minimum length needed to enable maximum load carrying capability at minimal weight. Automated Dynamics (ADC) takes this technology to a new level of achievement through developing and perfecting in-situ consolidation of thermoplastic composites.
This market-differentiating capability has enabled ADC to manufacture structures with processing and performance requirements that cannot be mutually met by other methods. For example, we currently manufacture a ten meter long, multiple inches thick, wall part containing temperature sensitive internal components. Continuous fiber reinforcement allows the part to handle the impressively high shock loads to which it is tested. This eliminates the use of a metal or thermoset-based structure, keeping the part’s overall weight to a minimum.
High Throughput AFP
As with any technology, in-situ AFP has traditionally had its limitations; namely, processing speed. It has been limited to applications where extreme performance outweighed a low cycle time, which is acceptable only in low volume manufacturing. However, this limitation is easily overcome by more conventional two-step AFP processing. Conventional AFP works with fast tape placement, followed by thermal consolidation. Automated Dynamics can apply tape at speeds exceeding 1 m/s. Full (thermal) consolidation is achieved during a secondary molding, pressing, or stamping stage. Despite the additional step, overall cycle times are reduced.
The process can also be reversed such that tape is rapidly applied in specific locations to molded preforms. In each case, very high strength, lightweight structures with increased complexity can be achieved while maintaining a continuous operation. Full automation for continuous manufacturing and lower cycle times can be achieved through the use of a part transfer robot.
Automated Dynamics has tested an extreme version of this technique to evaluate our capability limits. A composite tube to replace titanium in a high strength application was fabricated by in-situ AFP as a straight, fully consolidated billet, then bent in a mold using a hot press. The bend was specified for a nearly four millimeter wall tube at a precise angle and location along the length with no ID kinking or creasing allowed. Despite only warming to below the resin melt temperature, a dozen replicate parts were successfully produced. Of course, bending a fully consolidated billet requires greater attention to fiber orientation as it’s balanced with ply slippage to allow bending in a mold.
For more information on our work with Automotive clients, contact:
Reid Hislop, Business Development Manager
518.377.6471 ext.275| Email Reid