Resin transfer molding
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RTM (Resin Transfer Molding) Is a closed mold process for molding fiberglass products. It does not require metal molds or high pressure mold closing systems. It is ideal for part volumes from 500 to 10,000 parts per year. It's a process suited for short and medium production runs and is employed in many different transport applications (truck cabs are an example).
When considering closed molding options for composite production, there are a number of possibilities. For high volume production, compression molding process produces low cost parts, but requires a high capital investment in presses, infrastructure and tooling. Also the difficulty in controlling fibre orientation in the part limits its applications to non-structural components. At the other end of the spectrum, vacuum infusion molding, requires very low capital investment, but produces cycle times similar or slower than traditional open molding. Resin Transfer Molding stands in the gap - able to produce mid-range volumes of parts at a moderate capital investment. Processes such as pultrusion and filament winding offer continuous fibre reinforcement but are limited to certain component geometries. On the other hand, the fibre orientation can be controlled very easily in case of RTM making the process suitable for even structural applications. One notable example being propeller blades for aircraft made by RTM.
