The 2 Ways to 3D Print with Carbon Fiber

The 2 Ways to 3D Print with Carbon Fiber

The high costs associated with manufacturing and fabricating have kept carbon fiber out of reach for some industries. As a result, the composites industry has been working hard to develop new technologies and processes that could help bring prices down. One of those technologies is 3D printing. It is a technology that is showing great promise.

Imagine being in charge of a car company looking to be the first to market a long-range electric vehicle. One of the vital parts you need for your car would be best if made from carbon fiber, but you cannot justify the cost of manufacturing. You settle for aluminum instead. But what if your carbon fiber supplier proved you could manufacture the part, via 3D printing, without breaking the budget. Would you go for it?

That's really where our industry is right now. New 3D printing techniques applied to carbon fiber and other composites offer a lot of promise for producing both individual parts and finished products at a fraction of the cost of manual layups and autoclave curing. Right now, there are two ways to 3D print with carbon fiber: chopped carbon fiber printing and continuous carbon fiber printing.

1. PRINTING WITH CHOPPED CARBON FIBER

Carbon fiber exists as a group of aligned carbon strands that act a lot like a thread. Each strand has a very high strength-to-weight ratio, which is what makes carbon fiber reinforced materials stronger than steel and aluminum but still lighter. To 3D print with chopped carbon fiber, strands of carbon fiber thread are chopped into small pieces.

Those small pieces are combined with a thermoplastic material, fed through a printer head, and laid down to create the desired part in place. As for the thermoplastic material, it takes the place of the epoxy resin normally used with manual layups. Because resin doesn't work well with 3D printers, a thermoplastic material that can be heated and melted must be used instead.

The finished product resulting from chopped carbon fiber printing is more or less a carbon fiber reinforced plastic. It is much stronger and more durable than alternative materials, but it is not as strong as it could be due to the embedded fibers being chopped into small pieces. When we need something stronger, we turn to continuous carbon fiber printing.

2. PRINTING WITH CONTINUOUS CARBON FIBER

A part 3D printed using this process is also a carbon fiber reinforced plastic. However, it is a stronger and more rigid material due to the differences in printing. Rather than using fibers chopped into small pieces, this process involves a continuous thread of carbon fiber combined with the thermoplastic material.

To accomplish this, two separate printheads are used. Carbon fiber thread is run through one printhead while the melted thermoplastic is forced through the other. The two combine into a single print-stream at the point of output. That single stream is then laid out, layer by layer, to print the desired part in place.

An advantage of this printing method is the ability to increase or decrease strength as necessary. For example, an engineer may be working with a part that needs extra strength at one particular stress point. By modifying the printing program, the strength can be increased in that one area alone. This allows for more customization of printed parts.

Carbon fiber is an excellent manufacturing material that could eventually replace steel and aluminum entirely. But in order for that to happen, production costs have to come down. The advent of 3D printing is moving our industry in that direction.