Technology

Nissan improved the manufacturing methods of carbon fibre parts

Carbon fibre is commonly used in supercars, racing cars, airplanes and luxury yachts. It is because it is a very expensive material. Carbon fibre is very light and very strong, but it would be very difficult to use it in more casual automobiles. But maybe that’s about to change – Nissan cas developed a new cheaper  way to manufacture carbon fiber reinforced plastics.

From 10 to 2 minutes – C-RTM can seriously speed up the manufacturing of carbon fibre parts. Image credit: Nissan

The reason why carbon fibre parts are so expensive is because the manufacturing process is extremely labour-intensive. People need to cut out parts from carbon fibre, layer them and put this thing into a special mold. The part is then compressed and resin is forced into it. It hardens because of heat and pressure. This stage of the manufacturing process takes around 10 minutes, which is a lot, but several years ago huge autoclaves used to be used for that and it used to take 3-4 hours.

Nissan found a way to improve the conventional resin transfer molding (RTM) process and created a C-RTM (compression-resin transfer molding) process. First of all, the molds themselves can be designed quicker using novel computer simulations. These simulations help optimize the flow of the resin. There are grooves in each mold, which help the resin to flow better, covering the entire part much more efficiently. Secondly, the molding process itself is a little different. In the RTM process resin is injected once the mold is closed. In the C-RTM process mold is left a little bit open, which leaves more space for the resin to flow. Then the mold is closed, forcing the resin into the carbon fibre material.

Results are very good. Where RTM takes 10 minutes, C-RTM only requires 2. This could cut down on manufacturing costs quite significantly, allowing for more carbon fiber reinforced plastics to be used in relatively cheaper cars. And this is very important.

Carbon fibre parts are 50-60 % lighter than steel equivalents and yet they are as strong or even stronger. They are also incredibly rigid. This is very important not just for sports cars, but also for electric cars and hybrids. Batteries are incredibly heavy, making the entire vehicle quite massive. A light car is an efficient car, which means that manufacturers will have to find ways to compensate for that growing weight. One of the ways to do that is employing more composite materials, such as carbon fibre.

But not all drivers will be happy about seeing more carbon fibre in their cars. Sure, it looks cool and is very strong, but it is also very expensive to repair. Despite advancements in the manufacturing process, carbon fibre is never going to be as cheap as steel. And its failure mode is cracking and breaking, while metal bends and can be repaired fairly cheaply. On the other hand, composite materials do not rust, which is a huge advantage. 

 

Source: Nissan


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