5 Fascinating Uses of Carbon Fibre in Additive Manufacturing

10 November 2022

[Image Source: Dynamism]

 

Extremely light yet stronger than steel, carbon fiber has been favored for its outstanding resilience as a manufacturing material for many years. Now, its utilization is augmenting the properties of 3D printed parts.

Additive manufacturing consistently favours particular groups of materials, with ABS and PLA claiming the highest popularity. Indeed, solid reason backs this trend – as thermoplastics, both materials are malleable enough to undergo the extrusion process involved in Fused Filament Fabrication (FFF), one of the most common AM technologies. 

However, this measure of pliancy proves to be a double-edged sword.   

Though ensuring the simplicity of the printing process, these very same qualities endow parts with insufficient levels of strength for high-stress applications. This is a particularly current issue; with manufacturers increasingly turning to AM for end-use part production rather than prototyping alone, conventional thermoplastics sometimes just don’t make the cut. 

Carbon fibre can offer a solution. 

Frequently integrated into materials like ABS and PLA, carbon fibre is the secret ingredient taking AM products from relative frailty to a toughness not to be reckoned with. Alongside heightened temperature tolerance and increased thermal resistance, its prize property is its outstanding strength to weight ratio, investing lightweight forms with immense durability. 

In this article, we will run through some of the most interesting applications of carbon fibre in 3D printing over recent years. Read on to discover just how diverse the applications of this incredible substance can be. 

How Exactly is Carbon Fibre 3D printed?

 

Before we dive into any specific examples, let’s unfold the precise mechanisms by which carbon fibre is interwoven into AM processes. 

There are two primary modes of carbon fibre 3D printing; the distinction between the two lies in whether the fibre used is chopped or continuous. 

Chopped fibre reinforced materials, as the name indicates, intersperses tiny fragments of fibre into the chosen thermoplastic. Effectively, this takes some of the responsibility of handling stresses to the product off of the thermoplastic’s shoulders. Conventionally ‘weaker’ substances are in this way bolstered with greater strength than they would otherwise be capable of. 

This constitution has the central asset of not requiring any specialized technology for production. Standard FFF procedures can be followed, with the added bonus of the end result sporting more wear, tear and grit. 

Yet, such properties are not guaranteed. Two important variables are at play when determining the final performance of carbon fibre reinforced products – the length of each fibre segment, and the quantity of fibres present overall. Milled carbon fibre powder, for example, contains very short strands. The result is consequently weaker than the strength grade conventionally attributed to carbon fibre reinforced materials. 

The second kind of material is composed of ‘continuous fibres’, the antithesis of the previous substance. Here, variants of traditional deposition printing must be employed: Continuous Fibre Fabrication (CFF) is one example. Here, extruding through two nozzles, a thermoplastic cross section of the product is distributed before the continuous fibre strand is ironed into this layer, this exchange repeating until the final part is complete. 

Though such a composition necessitates an entirely distinct machining process, there are compelling reasons to make the leap and invest in the additional technologies. 

Unlike its chopped counterpart, the structural continuity of fibre is powerfully leveraged in CFF, granting parts even greater degrees of toughness. This is partially due to the consistent spread of the fibre throughout the product – whilst clippings of fibre can be concentrated unevenly throughout an item, continuous fibre is ironed in at regular intervals. 

A classic pros and cons list here emerges – the easier and cheaper option is slightly less effective, whilst more expensive alternatives garner optimum results. 

Either way, opting for a carbon fibre reinforced material can considerably improve the performance of parts post production. Here are five examples of manufacturers employing its qualities to push the limits of manufacturing, shaking up the sector down to the fibres of its being. 

 

1) 3D Printing Without Supports

Amongst the many positive qualities driving additive manufacturing’s escalating popularity across industries, waste reduction is a particularly important one. Only the most necessary materials need be used to produce a build, differing mightily from the immense waste subtractive manufacturing gives off. 

Yet, despite this, there does remain one way in which additive manufacturing ‘wastes’ material. Namely, in many cases, parts can only be formed with the help of supports. 

Though not all AM technologies extend this condition – such as those involving a powder bed, which naturally supports the part on its own – methods involving extrusion typically remain bound by its necessity. 

In some select cases, supports can be recycled and reused. On the whole, however, this material is cast to the side.

Following the recent discoveries of a research team at Colorado State University, capitalizing on the qualities afforded by carbon fibre, this inevitability may be set to change. 

For some time, the possibility of printing substances capable of immediately hardening – and so rendering supports void of purpose – has been eagerly sought out in AM R&D. Fibre-filled thermo-set composite resins have been identified as ideal for this possibility, but slow curing rates mean that extruded materials droop out of shape before they have time to harden. 

Colorado State University’s researchers did not give up. In a breakthrough discovery, they developed a ‘frontal polymerization’ strategy, involving the collaboration between their specially made thermo-set resin filled with chopped carbon fibre with a heated printing bed. As the material emerges and touches the bed, an exothermic reaction is sparked; by exactly aligning the extrusion rate with the rate at which the reaction progresses, material can be hardened into shape with game-changing immediacy.

The achievement of this result is thanks in considerable part to the presence of carbon fibre in the material employed. According to an article by 3D Printing Industry, “the addition of the carbon fibres was found to enhance both the rheological behaviour and thermal conductivity of the composite resin”. 

Kickstarting this list with an example of carbon fibre reinforced material’s place in R&D, the expansiveness of its applications in additive manufacturing spaces is already proving to be substantial. 

 

2) Spare Part Production in Italian Speed Championship

Moving from development to end-use production, carbon fibre has also been integrated into spare-part production, an AM application which has recently been on the rise.

In 2019, 3D printer manufacturer WASP released the Delta WASP INDUSTRIAL 4.0, a printer supporting carbon-fibre material production. This functionality suited it perfectly to a particularly thrilling use-case: spare part production for motorbikes competing in the Italian Speed Championship. 

Spare parts have always been some of the most frustrating to supply. Invented to offer a solution in unexpected circumstances, they are by nature both contingent and absolutely necessary. When not being used, traditionally manufactured spare parts tend to sit around in echoing warehouses, wasting valuable space. However, in times of crisis, they can be the make-or-break component needed to bring resolution to a mechanical problem. 

Now, carbon fibre is entering the AM spare-part production equation. The ability to print parts on-demand is increasingly being recognised as an invaluable possibility, especially in high-velocity environments like motorbike racing. This concerns both the near back-to-back nature of the racing rounds, and the races themselves. 

Bringing together racers from around the country, along with their varied and intricate bikes, the ability to produce any and all parts necessary quickly enough to patch up damage before another race is priceless. 

Most importantly, though, it is crucial that the parts themselves are able to withstand the harsh conditions of a bike race. Contemporary motorbike design can propel riders over 200mph; a part unable to withstand impact at immense speeds is not worth installing at all. Indeed, fitting an insufficient replacement could fatally interfere with the motorcyclist’s performance, either hindering their chances at victory or, more seriously, catalysing a serious accident. 

The key to printing spare parts successfully, then, is to build up a well-founded certainty that the replacements will function just as well as their predecessors did. This trust is central. It is no surprise, then, that the properties attributed to carbon fibre – durability fit to withstand intense stress, and lightness streamlining mechanical design – utterly suits it to the task. 

 

3) The Automotive Industry and Aston Martin’s DBR22

Lingering within the realm of AM vehicle production, Aston Martin released its dashing new DBR22 model this summer. One of its standout qualities, its lightness, owes in large part to its ample inclusion of 3D printed carbon fibre reinforced parts. 

The rear subframe of this car is one such element. As a large structural component, the quality and strength of the subframe is crucial to ensuring the car’s adequate performance, acting as a support to many of the vehicle’s other units.

In fact, a faulty subframe could garner similarly fatal results as a lacking motorcycle spare part could afford, susceptible to the various accelerations, brakes and bumps characterizing a vehicle’s life.

Again, the choice of AM carbon fibre reinforced material for this part is thus an optimal one, once more thanks to the strength to weight ratio achieved as a result. As a supercar, speed sits at the centre of mechanical design; minimizing the weight of individual units enables adherence to this vision. Carbon fibre not only secures this important condition, but does so without sacrificing the stiffness needed for the subframe to function successfully.

The DBR22’s subframe underwent design input from Divergent Technologies, the company also responsible for the iconic Czinger 21C hyper car, taking the automotive industry by storm. According to Kevin Czinger, Divergent and Czinger Vehicles CEO, the possibility of widely adopting this approach to subframe design could be transformational for original equipment manufacturers (OEMs).

 

One thing is clear: carbon fibre additive manufacturing is taking the vehicular sector by storm. 

 

4) End-part Production and LACE’s Jewellery Line

 

The use of carbon fibre reinforced 3D printed materials is not limited to the mechanical sphere alone. To move this article in an entirely fresh direction, luxury designer jewellery brand LACE by Jenny Wu designed a 3D printed carbon fibre infused jewellery line in 2021, collaborating with printer manufacturer Impossible Objects. 

Though the use-case for this material may initially seem less obvious than its applications in automotive contexts, the fashion industry is no less in need of durable and lightweight materials.

Each piece included in LACE’s line – a collection of four items, including a cuff, earrings and two rings – reimagines previous items designed using different materials. The revolutionary lightness of the products are in this way granted a chance to shine in comparison with their stainless steel and sterling silver equivalents. Yet, once more, this quality does not come at the price of fragility.

Additively manufacturing carbon fibre reinforced substances unlocks access to unparalleled harmony between visuality and functionality. Type ‘carbon fibre ring’ into a Google search and your page will fill with images of broadly simplistic designs, displaying an overall shyness towards and incapacity for pushing creative boundaries.

Design freedom, however, is 3D printing’s forte. LACE refreshingly prides itself on the durability of its products whilst also infusing their designs with flowing elegance. Physical toughness need not overwrite visual softness. 

Both comfortable and long-lasting, LACE has identified the project as “the first jewellery collection that has ever been produced with this new technology”, paving a new way forward for optimized design. 

 

5) 3D Printer Manufacturing and Atom 3.5

As this article has endeavoured to convey, the pairing of 3D printing technology with carbon fibre reinforced materials has diverse applications. Bringing this ‘combination’ to its extreme, Taiwanese 3D printer manufacturer Atom has integrated carbon fibre into the structure of their Atom 3.5 machine. 

This aspect of the printer was not what drew the attention of the media upon its release. Instead, articles honed in on its unique dual extrusion mechanics, with a toolhead supporting two nozzles that can be respectively activated during the same build. These can print using different materials, enabling constitutional complexity within individual parts. 

Though this presents exciting opportunities, there are other features of this printer that must not be overlooked; notably, the connecting rods supporting the toolhead implement carbon fibre. As Kerry Stevenson notes in his Fabbaloo article on the subject, this application suits the material well, “as the stiffer the rods holding the toolhead are, the more accurate the toolhead positioning will be”.  

Indeed, this structural feature has a close bearing on the feature that piqued the interest of the press. The rods link to the toolhead, the toolhead to those innovative nozzles; the resilience of the rods thus ultimately impacts the success of the print, an especially important feature considering that the nozzles themselves are subject to shifts. 

With this example, we have come full circle. It would be possible for a carbon fibre accommodating 3D printer to print carbon fibre parts for another 3D printer, the AM version of finding a genie and wishing for more wishes. 3D printing not only uses carbon fibre based materials in its prints, but can also be mechanically enhanced through its presence, too. 

 

Future of Carbon Fibre AM

 

Just last week, Data Bridge released its report on the carbon fibre market, expecting an arrival at $8 billion in revenue by 2029, sporting a CAGR of 8.95%. They put this down in part to the “rising utilization of carbon fiber in 3D printing” specifically. 

As the demand for additively manufactured goods inflates globally, it would not be surprising to witness a knock-on expansion in carbon fibre’s presence market-wide. 

However, there is still some way to go towards optimizing its applications. This August, for instance, on demand 3D printing service provider 3D People made the decision to cut CFF from their list of available technologies, citing its expense as a key decision driver. They raise concern that interest in this technology specifically is declining.

With such complications still plaguing the carbon fibre AM market, MES & workflow solutions like AMFG can offer crucial rectification. If carbon fibre material implementation is to scale – with mass production shimmering on the horizon – then a means of amplifying efficiency will be central to cutting costs where the technology itself is already priced highly. 

Nonetheless, the capacity to integrate carbon fibre into AM production has indubitably helped to strengthen 3D printing’s case against traditional manufacturing. The future of the material’s coupling with this technology is bright. 

 

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Enjoyed this? Check out our last article, ‘Demystifying Metal Additive Manufacturing: An Introductory Guide’.