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CRTM™ Panels

Sandwich panels made using the continuous resin transfer molding process provide structural integrity, and are lightweight and cost effective

CRTM™ panels are high quality composite sandwich panels with tailored, multi-axial fiber reinforcements, high-fiber volume contents and very low void content. These custom-engineered products are available with a wide variety of core materials, including end-grain balsa, foam or engineered woods. Laminate skin face-sheets are also available with continuous fiberglass and/or carbon fiber reinforced polyester, vinyl ester and epoxy or custom resins.

CRTM panels are specifically designed for applications needing a high stiffness-to-weight ratio. Panels are custom engineered to meet customer needs by varying core thicknesses to affect stiffness, core materials to affect weight, fiber to modify the stiffness-weight ratio, and resin material to affect strength.


  • Reduced manufacturing costs due to manufacturing efficiency and superior lamination
  • Superior strength-to-weight ratio
  • Vibration damping and acoustic insulation
  • Improved thermal insulation
  • Reduced component complexity compared to metal
  • Unlimited continuous lengths with widths of up to 108 inches

CRTM - Continuous Resin Transfer Molding

Sandwich panels manufactured with the CRTM (continuous resin transfer molding) automated pultrusion process are cost effective, lightweight, structural-quality composite panels suitable for a wide variety of applications. Consistent product quality is assured by using computer-controlled programmable logic circuits. Unlike typical wet bath pultrusion processes, Glasforms’ injection pultrusion process effectively minimizes volatile organic formulation (V.O.C.) emissions. At the same time, uses lowest-cost basic materials to produce a part with uniform thickness, consistent mechanical properties and highly repeatable quality.

While similar to pultrusion, the CRTM production method offers more consistent quality throughout the panel. This is possible because, unlike a pultrusion process where the resin is applied to the fiber before it enters the die, the CRTM machine allows the resin to be injected directly into the die for better control of fiber alignment and resin kinetics. This process yields high performance, constant cross-section composite structures that offer superior quality and are more cost efficient than current hand lay-up processes.


CRTM panels can be useful to a variety of industries. Naval architects and boat builders find the lack of water absorption, minimal weight, and durability of Glasforms’ CRTM™ panels ideal for marine applications such as structural bulkheads, transoms, decks/soles, and interior walls. Large truck, trailer, RV, coach and mass transit vehicles implement CRTM panels for walls, floors, and structural bulkheads for weight savings, as well as an overall reduction in the total number of components and secondary fabrication. CRTM panels will not rot or corrode, thus weight reduction and increased insulation allow CRTM panels to be used as a replacement for traditional steel and plywood building materials, as well as many others.

Process Overview

The CRTM process begins as dry reinforcements are continuously pulled from the creel system into the die through the fiber/fabric preforming guides that align the material into a near net shape. Before the preform reaches the resin injection region, it is compacted closer to the final profile dimensions in the initial portion of the die. In the injection region, resin under a steady pressure is injected into the preform through multiple injection ports to maintain the required flow rate. The partially impregnated preform is then pulled through the wet-out/tapered region where it is thoroughly impregnated through a multi-dimensional resin flow. Next, the preform is drawn into the die’s cure region where the temperature profile is controlled in multiple heat zones.

Optimization of the temperature profile is necessary to assure proper consolidation while maximizing the degree of conversion. After exiting the die, the warm product cools at ambient conditions before it reaches the puller shuttles. Process speed variations must be properly combined with the injection pressure and the thermal profiles in the die in order to attain both superior product quality and economic throughput rates. At the end of the process line, the product is cut to length with the use of a synchronized flying cut-off saw.

Name Category Description  
Glasforms CRTM - Product Bulletin
Product Bulletin
Product description, value solution, key characteristics, markets and applications of Glasforms™ CRTM™ Continuous Resin Transfer Molding Sandwich Panels
Glasforms™ and Polystrand™ Composite Sandwich Panels for Marine Industry - Application Bulletin
Application Bulletin
Capabilities, features, benefits, impact, and technical data for Glasforms™ and Polystrand™ composite sandwich panels for marine industry applications
Glasforms™ and Polystrand™ Composite Sandwich Panels for RV Industry - Application Bulletin
Application Bulletin
Capabilities, features, benefits, impact, and technical data for Glasforms™ and Polystrand™ RV composite panel applications 
Glasforms™ and Polystrand™ Railcar Composite Panels - Application Bulletin
Application Bulletin
Capabilities, features, benefits, impact, and technical data for Glasforms™ and Polystrand™ railcar panel applications

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