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Understanding Tension and Compaction in AFP: Beyond Traditional Debulking


Carbon Fiber Reinforced Plastics (CFRPs) have revolutionized the materials world with their unparalleled stiffness-to-weight ratios. As industries strive for efficiency, understanding the nuances of processes like Automated Fiber Placement (AFP) and debulking becomes paramount.

AFP Process: A Brief Overview

In the realm of composite manufacturing, the AFP process stands out as a game-changer. Here, an AFP head, strategically positioned at the end of an industrial robotic arm, meticulously places multiple strips of composite material tapes, or tows, onto a designated tool surface. This process, often simulated using advanced digital twin software like AddPath, ensures precision and repeatability. The key to AFP's success lies in its meticulous attention to detail: from the heating and compaction used to ensure adhesion to the tension applied to each tow for accurate placement. Together, these rows of tows form courses, which when layered, create a robust laminate.

The Necessity of Debulking

Traditionally, to enhance the strength-to-weight ratio of CFRPs, debulking has been the go-to process. By compacting dry fibrous reinforcement before resin infusion, debulking reduces the inter-fiber distance, effectively increasing the fiber volume fraction. This macroscopic effect, while beneficial, has microstructural implications that remain under-explored. The process often requires multiple stages: after the first ply, every three subsequent plies, and post the final ply. This ensures even consolidation and air removal, crucial for the laminate's integrity. The detailed steps, as depicted in Figure 1, emphasize the care and precision involved.

Eliminating Debulking with AFP Winding

The brilliance of AFP lies in its ability to potentially bypass the traditional debulking process. The high tension and compaction pressures applied during AFP Tape winding, as discussed earlier, can be so substantial that they negate the need for separate debulking. The combined tension and compaction pressure applied during the Automated Fiber Placement (AFP) of a tank can be set to very high levels, potentially making debulking unnecessary. For instance, in the video you referenced, the tension was set at 100N. This translates to approximately 104kPa for a 1/4'' tape. When you add the compaction force from the AFP, which is 250kPa, the total comes to 350kPa. This is significantly higher than the typical 194kPa pressure used for debulking three plies.

Thick Winding and Its Advantages:

With AFP's layer-by-layer approach, manufacturers aren't constrained by thickness limitations. This flexibility opens doors to diverse applications, from hydrogen tanks to electric motor sleeves and even sub-sea motors. Each application benefits from the enhanced structural integrity and reduced weight offered by thick winding.

Applications in Focus:

Hydrogen Tanks: With the push for sustainable energy, hydrogen storage requires tanks that can withstand high pressures without compromising on weight. AFP's precision and the strength offered by thick winding make it an ideal choice.

Thermoplastic type V tank made with AFP-XS
Thermoplastic type V tank made with AFP-XS

Electric Motor Sleeves: In the rapidly evolving electric vehicle market, motor efficiency is paramount. AFP-manufactured sleeves offer the strength and precision required for optimal performance.

Sub-sea Motors: Operating in challenging underwater environments demands materials that can resist pressure and corrosion. Again, AFP stands out as the manufacturing process of choice.


The synergy between AFP and debulking represents the future of composite manufacturing. By understanding and harnessing these processes, industries can achieve unparalleled efficiency, precision, and product quality.

What's Next!

Discover the future of composite manufacturing with Addcomposites! Here's how you can get involved:

  1. Stay Informed: Subscribe to our newsletter to receive the latest updates, news, and developments in AFP systems and services. Knowledge is power, and by staying informed, you'll always have the upper hand. Subscribe Now

  2. Experience Our Technology: Try our cutting-edge simulation software for a firsthand experience of the versatility and capability of our AFP systems. You'll see how our technology can transform your production line. Try Simulation

  3. Join the Collaboration: Engage with us and other technical centers across various industries. By joining this collaborative platform, you'll get to share ideas, innovate, and influence the future of AFP. Join Collaboration

  4. Get Hands-On: Avail our educational rentals for university projects or semester-long programs. Experience how our AFP systems bring about a revolution in composite manufacturing and leverage this opportunity for academic and research pursuits. Request for Educational Rental

  5. Take the Next Step: Request a quotation for our AFP systems. Whether you're interested in the AFP-XS, AFP-X, or SCF3D, we are committed to offering cost-effective solutions tailored to your needs. Take the plunge and prepare your production line for the next generation of composite manufacturing. Request Quotation

At Addcomposites, we are dedicated to revolutionizing composite manufacturing. Our AFP systems and comprehensive support services are waiting for you to harness. So, don't wait – get started on your journey to the future of manufacturing today!


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