How Does the VARTM Method Work?

February 28, 2021 / Painted Rhino
How Does the VARTM Method Work?

There are many ways to manufacture composite structures. The vacuum assisted resin transfer molding process produces fiber-reinforced plastic parts for various purposes. These fiberglass items have many applications in multiple industries.

How Does the VARTM Method Work?

VARTM uses materials including e-glass, high-performance fibers and low viscosity resins. This technique is a low-pressure closed mold system that involves adding vacuum at the molding tool's exit vent. An e-glass fiber sits between two molds as a reinforcement. A vacuum bag seals the mold, and external atmospheric pressure compresses the fiber against the mold surface. Replacing the top portion of a mold tool with a vacuum bag assists the resin flow infused into the fiber layup. Low vacuum pressure strengthens the resin and removes air bubbles from the preform.

What Are the VARTM Processing Steps?

VARTM techniques generally have three processing steps. Each step influences the quality of the final resulting component:

  • Material preparation: Place preforms, fibers and reinforcing materials in the mold. Resin mixing and degassing blends components. Digital leak rate equipment monitors the leak rate to ensure quality.
  • Infusion: The flow behavior in VARTM has significant complexity compared to traditional resin transfer molding. The vacuum pressure compacts the preform and drives the resin through the reinforcement.
  • Post-infusion: Low viscosity resin bleeds into the vacuum trap, taking excess resin and moving it toward the vent. This volume loss decreases thickness and improves fiber volume fraction.

What Industries Use the VARTM Process?

This method applies to virtually all sizes of composite structures and produces large, complex FRP pieces. The VRTM technique helps manufacture parts for various industries:

  • Transportation
  • Wind energy
  • Infrastructure
  • Aerospace applications
  • Marine market
  • Medical
  • Recreational

This technique is a practical and cost-efficient way to construct large parts that are exceptionally durable yet lightweight. It provides a valuable solution for manufacturing components such as:

  • Large composite panels
  • Wind turbine blades
  • Bridge beams
  • Boat hulls
  • Aircraft Fuselage Sections
  • Aircraft Landing Gear Doors

Why Choose Vacuum Assisted Resin Transfer Molding?

The VARTM method is a cost-effective manufacturing technique that produces strong, high-quality composite parts. It allows manufacturers to create large-scale elements that would be cost-prohibitive with other forms.

There are many advantages to VARTM over traditional RTM methods:

  • This approach produces complex, aerospace-grade components.
  • The process does not require special equipment like an autoclave.
  • The scalability for large structures eliminates the need for making numerous small elements, reducing manufacturing costs.
  • VARTM produces parts with both dielectric and mechanical strength. 
  • Lower tooling costs minimize overhead.
  • It has the potential for room temperature processing.
  • It makes high-performing composite components.

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