Vacuum Assisted Resin Transfer Molding (VARTM)
The demand for high-speed production has pressed the industry to increasingly replace traditional
processes such as hand layup with better and automated alternatives
of fabrication. Among these common alternatives is VARTM.
VARTM Overview
Vacuum Assisted Resin Transfer Molding, abbreviated to VARTM, is also called the Vacuum Injection Molding or Vacuum Infusion Molding process.
In simple terms, it’s a closed mold composite manufacturing process – These composites are rigidly molded to achieve thin, flexible membranes and geometry over the fiber. Atmospheric pressure from the outside compresses the fiber firmly against the surface of the mold while under vacuum.
Infusing the resin through the mold where a vacuum is applied to the mold is key to VARTM. The process utilizes a bottom section mold and a vacuum bag, differentiating it from other closed mold processes.
VARTM Process
VARTM is a process where the resin matrix is drawn under vacuum into a preform, no pressure other than the vacuum pump is used. This is why it operates with low-cost tooling and allows for relatively inexpensive production of larger parts.
High-performance fiberglass fibers, along with low viscosity polyester or vinyl ester resins, help create a superior quality composite. A vacuum-tight seal is formed by placing fiber reinforcements in a one-sided mold, covered by a vacuum bag from the top. Strategically placed ports allow the resins to make their way into the mold. The vacuum draws the low viscosity resin through the means of flow channels that facilitate fiber wet-out.
The resin to fiber ratio determines the performance and strength of the final product. The type of fiber reinforcement chosen determines the mechanical strength, whereas resins determine corrosion, temperature resistance and surface finish. It’s extremely important to avoid air leakages in vacuum infusion molding, as it may cause defects in the final product.
VARTM Process Advantages
The vacuum resin infusion process offers the benefit of creating larger and aerospace-grade parts with economical equipment costs. The processing and scaling can be done at room temperature. It’s also a cost-effective and efficient alternative to the more time consuming and labor-intensive processes of hand layup.
VARTM Process Applications
The vast majority of composite molding applications fall into the following fields of use:
Ground transportation
Marine
Aerospace
Wind energy
Industrial
Recreational
Need further assistance in understanding the vacuum injection molding process? Want to know how it can boost your manufacturing business success? We’re here to help! Call Verretec Composite Materials, LLC professionals at (724) 543-2333, or leave us your business inquiries here. We’ll get back to you with an appropriate solution.
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