Composites: Additive Manufacturing vs Machining

06 June 2024
Photo credit Electroimpact via Additive Manufacturing

What do a bridge, an F1 car and an Olympic windsurfing board have in common?

Answer: they may all be made of composite materials.

Composites have a long history, dating back to the invention of the lightbulb. However, recent technological advances and higher demand from the aerospace and automotive sectors has seen huge growth for the market. 

When the composites trade association, Composites UK announced their strategy back in 2016, they predicted that composites would grow with a CAGR of 6.5%. Now the market is set to grow with an annual CAGR of 10.8% reaching $181.7 billion by 2028

This increased demand raises questions about which manufacturing processes to use when working with composites.

Additive manufacturing has long had a foothold in composite manufacturing and the two technologies have worked together to drive innovation from printing 3D tools in space to drone manufacturing. But where does this leave machining?


 

Why composites?

Photo courtesy of Carlos Aranda via Unsplash
Photo courtesy of Carlos Aranda via Unsplash

The main concept behind composites – combining materials to make new materials – is a practice almost as old as civilisation. 

When we talk about manufacturing composites, we’re looking at materials like carbon fibre, fibreglass, or Kevlar. Carbon fibre, also known as graphite fibre, composites are polymers made from, strong crystalline filaments of carbon that are used to strengthen materials. In some cases, it can even replace metals like aluminium.

According to Composites Construction UK, the use of carbon fibre in construction contexts is less energy-intensive and can be applied with minimal changes to existing structures. This means that instead of demolishing structures entirely and expending more time, energy and materials rebuilding them, bridges and buildings can be given a new lease of life.

In the automotive sector, cars made from composites are stronger yet lighter than their counterparts made with traditional materials. This is not only a key consideration for safety but a lighter car means less energy needed to move the car making it more efficient. 

In fact, this demand from the automotive industry is a key factor driving demand for composites. The automotive composites market alone is projected to be worth $14.3 billion by 2028, double its value of $7.2 billion in 2022

AM or Machining?

 

 

Cockpit of full flight simulator from Reiser Simulation and Training Credit Reiser Simulation and Training.
Photo Credit Reiser Simulation and Training.

 

Additive manufacturing has been a game changer for composites. 

According to editor-in-chief of Composites World Jeff Sloan, additive manufacturing allows “more efficient and faster fabrication of parts that until a few years ago may not have been economically feasible using current composites manufacturing technologies.” 

Earlier this year brought the news that Murtfeldt Additive Solutions successfully manufactured a modular cockpit for a helicopter simulator using additive manufacturing processes. The company states that traditional manufacturing methods such as mould-based manufacturing processes have meant longer lead times and higher tooling costs.

Michael Ortmann of Reiser Simulation and Training who was responsible for the design and development of the project outlines how the advantages of AM aimed the project. He points out the benefits of AM’s “extremely short time to market, high build speed, lightweight construction, bionics, functional integration, and cost-effective manufacturing without the need for moulds, along with the merits of using granulates, to name just a few aspects.”

Evidently, additive manufacturing is going from strength to strength as far as composites are concerned, but what about machining?

Compared to AM, machining carbon fibre using cutting or milling techniques brings a host of challenges to manufacturers. According to Composites World, the strength and durability of these materials are a double-edged sword.

The heterogeneous nature of composites with its series of differing layers and materials makes it difficult to drill or mill. Therefore, in machining, there can be damage both to the material itself as well as the tools used.

 

The companies changing the game

 

 

Courtesy of IDEKO
Courtesy of IDEKO

 

 

Despite these challenges and additive manufacturing’s prevalence, it is beneficial for manufacturers to be able to machine composites. Milling and drilling capabilities are essential for processes such as achieving a smooth finish or creating specific features such as threaded holes or channels.

Luckily, there are companies working to overcome the challenges of machining composites and offer innovative solutions to manufacturers. The first of these is Compcut a specialist division of Sharp & Tappin Technology. Established in 2003, Compcut has spent decades looking to solve this precise problem and providing machining solutions including “Advanced Composite Saws and Precision Composite Routers”.

Compcut attended leading international composites show JEC World 2024, exhibiting their CNC cutting machine the ACS 300. The machine is designed for producing test samples using composite materials and features an enclosed work area to improve safety. 

Moreover, its accuracy means that test samples require no post-processing. Materials testing and consultancy business R-Tech Materials described the machine as, “a vital asset in helping to streamline our composite test specimen production flow.”

In May, technology and research centre IDEKO unveiled a new robotic solution for the machining of composites. The technology focuses on addressing the large amounts of dust generated in the machining of composites which can be toxic and contribute to health problems such as respiratory difficulties, dermatitis and conjunctivitis. According to IDEKO, their technology includes a workhead that sucks 100% of the toxic dust particles from the tool making the machining process safer.

Moreover, IDEKO’s technology allows a precision machining solution with high levels of accuracy, continuous vibration monitoring and monitoring processes with data that then gets recorded on the cloud and is ripe for artificial intelligence functionality to optimise productivity.

 

Specialist solutions

Image courtesy of Refitech
Image courtesy of Refitech

5-axis milling machines have brought vase possibilities to the sector, including for the machining of composites. In 2023, Dutch composite engineering company Refitech Composites Solutions announced its purchase of a 5-axis milling machine for use in its production of composite parts.

The 5-axis mill is manufactured by CMS Advanced Materials Technology, an Italian company that specialises in CNC machines and systems for composites processing. The CMS 5-axis milling machine seems to address all of the concerns around machining composites in one machine. 

The CMS 5-axis mill is enclosed to control dust, chips and noise and uses CMS Adaptive Technology to reduce cycle times on complex surfaces all while maintaining accuracy and the quality of the finish. 

These new technologies and machines could provide crucial for overcoming the challenges posed by machining composites. As the composite market grows, they may be seen increasingly on the shop floor. 

 

Final thoughts

 

Photo courtesy of Compcut
Photo courtesy of Compcut

The rise of composites provides new opportunities for stronger, lighter and more durable products, particularly in the aerospace, automotive and construction sectors. It is also crucial to develop ways to manufacture these products safely and without compromising the machine or the material.

Free from the limitations of other traditional manufacturing processes, additive manufacturing has emerged as a popular method of producing composites. However, machining processes also offer value and with more machines released with composite machining in mind, it may become easier than ever for job shops to access this growing market.

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