The Continuous Forming Machine

| Empowering manufacturers to reach new markets with lightweight, anti-corrosive, and infinitely shapeable parts through continuous production of long-fiber thermoplastic composites.

ASCC engineers inspecting a thermoplastic material in front of the continuous forming machine

Example Capabilities

  • Advanced Shapes
    with multi-axial reinforcement
  • Rotary Molding
    for rebar, surface deformations, etc.​
  • Tape Winding
    for piping, etc.
  • Transverse Bending
    for channel creation, etc.​
  • Curved Geometries
    for curved parts & advanced surfaces.
thermoplastic material undergoing tape winding under high heat inside the CFM

TECHNOLOGY

The Continuous Forming Machine (CFM) is a University of Maine-developed technology, based on pultrusion and thermoforming, used to manufacture complex thermoplastic Fiber Reinforced Polymer (FRP) parts. The CFM uses commercially available pre-saturated feedstocks such as UD tapes, fabrics, weaves, and more, which are heated to a viscous consistency and pulled/molded through a drive system – allowing for the creation of numerous thermoplastic parts.

Why Thermoplastic FRP?

  • High-strength
  • Lightweight
  • Reshapeable and weldable
  • Recyclable and low-impact processing

Thermoplastic Resins

a graph showing viable thermoplastic resins on a scale of workable temperature, and increasing performance vs decreasing cost, and split between amorphous and semi-crystalline thermoplastics.

Impact of the CFM

  • Industry scale manufacturing
  • Produces sustainable, recyclable, & reshapable thermoplastic composites
  • Enables multi-process collaborative manufacturing

CASE STUDY: Thermoplastic Composite Rebar

| A rebar with the same lightweight and corrosion-resistant properties as GFRP composite rebar, but it can be bent on-site and is fully recyclable.

Why Thermoplastic Composite Rebar?

  • Traditional Steel Rebar is heavy, costly to transport, highly susceptible to corrosion, and has a large carbon footprint.
  • Glass Fiber Reinforced Polymer (GFRP) Composite Rebar is corrosion-resistant, lightweight, and has a reduced carbon footprint, but cannot be field-modified or recycled.
  • Stainless steel rebar is corrosion-resistant and field-adaptable, but heavy and expensive.
  • Thermoplastic composite rebar maintains the benefits of all three without the added challenges!

Manufacturing with the CFM

The CFM is able to produce thermoplastic rebar at up to 12 ft/min. ​This process is fed by commercially available unidirectional UD tapes into a heating chamber. Any fiber selection can be used. Resin selection will be determined by ongoing durability studies. ​The thermoplastic material is then cooled and pulled through into the rebar shaft shape while also molding the rebar corrugations. ASCC is preparing rebar to meet requirements from ASTM, ACI, and AASHTO.

thermoplastic rebar on two rollers in the CFM, molding the corrugations onto the rebar.
A split image of two rebar cages made from field bendable thermoplastic rebar.

Thermoplastic Rebar Benefits

  • High Strength
    2x the tensile strength of steel rebar.
  • Corrosion Resistant
    Withstand prolonged exposure to harsh environments, while maintaining structural integrity.
  • Lightweight
    Weighs roughly 25% of steel.
  • Recyclable
    Enables closed loop recycling, as it can be made from recycled plastics.
  • Additional Benefits
  • Weldable, allowing for the creation of reinforcing grids. ​
  • Increased impact resistance vs commercial GFRP rebar.​
  • Electromagnetically inert for structures that contain sensitive medical or communication devices.​

Unique Manufacturing Processes

| The development of the CFM has opened the door for novel composites manufacturing processes

Thermoplastic Composite Periodic Multi-Curvature Surfaces ​(TCPMCS)

TCPMCS allows for the creation of structural surfaces with minimal material by optimizing the placement and shape of materials to meet performance goals.

Expanding CFM Capabilities

  • Pultrusion enables the production of continuous cross-section profiles, but the CFM leverages the innovation of thermoplastic forming to enable the continuous manufacturing of TCPMCS.
  • TCPMCS can be manufactured in various patterns, with both curved and flat geometries.
  • TCPMCS can be combined with each other, and/or skin layers to create complex structures.

TCPMCS Applications

  • Lightweight Sandwich Panels: TCPMCS can provide a lightweight and inexpensive core, providing significant strength and rigidity for composite sandwich panels.
  • Energy Dissipation: TCPMCS can be created with specific crushing behavior in order to absorb and dissipate blast or impact energy.
  • Ground Stabilization: TCPMCS can be utilized to stabilize loose earth. ​This could be utilized for rapidly constructing low-logistics or temporary roadways, deployable runways, or simply for erosion control.​
  • Drop-in-Place Infill for Large Format AM: TCPMCS can be utilized as a selectable infill core that can be dropped in place for higher manufacturing speed, exemplified in infill in 3D printing.
  • Undiscovered Innovation: TCPMCS applications are constantly being expanded
Uniquely egg carton-shaped roller attachment for the CFM that produces complex shaped thermoplastic sheets
Lightweight sandwich panel, two sheets of thermoplastic material with a complex wavy thermoplastic inside

Hybridized Advanced Additive Manufacturing (HAAM)

HAAM lowers additive manufacturing costs while boosting innovation potential by integrating CFM-pultruded Continuous Fiber Reinforced Thermoplastic (CFRT) structural components with Large Scale Additive Manufacturing (LAAM). It enables the production of complex, cost-effective end-use thermoplastic parts and structures.​

Why Hybridize?

  • Increasing Strength, Decreased Weight: Part strength increases up to 7x; up to 2/3 weight savings (depending on part geometry and slicing patterns).
  • Cost Reduction: HAAM decreases material needs, but also production time, saving cost.
  • Sustainability: HAAM supports closed-loop recycling, simplifying logistics as both the CFRTP and LAAM materials are the same thermoplastic systems. ​
  • Unlocked Innovation: HAAM allows for innovative use of slicing patterns, as well as unique geometries, to enable more use cases for LAAM parts.

HAAM Key Takeaways

  • Integrating CFM-produced parts into AM structures is achievable through diffusion bonding, reducing the need for adhesives and fasteners.
  • Using CFM-produced parts as stay-in-place reinforcing forms decreases the amount of AM material required for part stabilization during manufacturing.
  • Incorporating high-strength CFM thermoplastic parts reduces the amount of AM material needed to meet final structure performance requirements.

Future HAAM Development

  • Near term: enabling thermomechanical modeling tools to de-risk large LAAM projects and validating with CFRTP structural member behavioral studies. ​
  • Long term: The ASCC is breaking ground on the Factory of the Future (FoF), a first-in-kind testbed for large-format flexible digital manufacturing. With the FoF, new HAAM manufacturing processes are in development beyond overprinting.
diagram that shows a 3d printed structure wall that reads "LAAM house wall printed with filled window slots, requiring post-processing. an arrow points to the same wall with windows cut out and robotic arms attaching thermoplastic materials. It has three labels reading "HAAM house wall printed with window-ready recesses (supported with CFRTP during printing), reducing post0processing.", "CFRTP stay-in-place structural member", and "robotic placement"
front view of biome 3D