The roof using thermosetting CFRP
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The surfaces processed with the conventional technology (left) and the new technology (right)
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Toray Industries Inc developed a technology to improve the surface smoothness of thermosetting CFRP (carbon fiber reinforced plastic).

The company applied a CFRP-based roof made by using the technology to the "Teewave AC1" concept car, which was exhibited at Toray Advanced Materials Symposium 2016, a private show that took place from Oct 6, 2016, in Tokyo (See related article).

The roof of the concept car was formed by using an RTM (resin transfer molding) method, which makes a product by (1) setting carbon-fiber fabric in a metal mold, (2) impregnating it with epoxy resin (base material) and stiffening it and (3) removing the mold.

With a conventional RTM method, the roof is made by applying coating materials four times and conducting polishing three times after removing the mold.

On the other hand, with the new technology, after impregnating carbon-fiber fabric with epoxy resin (base material), more epoxy resin is poured into the metal mold before pressing. As a result, it is stiffened after increasing the thickness of the surface of the resin. After removing the mold, painting and polishing are conducted.

"The new method can increase surface smoothness more than the conventional method of repeating coating (application of coating material) and polishing after removing the mold," Toray said.

The new method reduces the number of processes, enabling to cut manufacturing cost. Toray considers that the new technology can also be applied to front hoods.