Machining Carbon Fibre: Challenges and Solutions
Carbon fibre is an impressive and powerful material. However, the machining process is notoriously challenging; it’s an abrasive product that requires careful management of waste, dust and tools.
Avoiding spiralling costs when machining carbon fibre hinges on having the correct methods, equipment and experience.
Below are three challenges you might encounter when machining carbon fibre, plus solutions and helpful advice.
Challenge – High scrapping costs
The manufacturing and custom moulding of carbon fibre material is an expensive process. The component has often attracted a significant value from previous operations before it arrives at the machine, so machinists have very little room for error. This means the cost of mistakes is much higher than other materials.
Solution – Prevention rather than cure
To avoid scrapping failed products, you need a reliable, repeatable, and consistent process that removes the need for operator intervention. Allowing the machine to check and verify itself prior to cutting, monitor itself and verifying that the end results meet expectations will remove the operator skills dependency and deliver a high quality consistent product.
Machining centres (such as those supplied by Kingsbury) typically feature on-machine probing facilities. These measure the product and ascertain if it has been located, clamped and cut correctly, meaning you find out about potential issues earlier in the machining process.
Correct cutting tools, methodologies, and cooling solutions are also essential preventative solutions. These are application-specific; your process could be wet or dry, or need totally different tools. It is essential you understand the product’s requirements and subsequent final finishing operations in order to select the right solution. We go into further detail on cutting processes in the next challenge.
Challenge – Carbon fibre is abrasive
Carbon fibre is an abrasive material and increases the rate of wear on the tools used to cut it. This is exacerbated by the temperature sensitivities associated with carbon fibre machining – the material has low thermal conductivity, and very little heat is carried away in chips. Additionally, using a dull edge for carbon fibre machining increases heat buildup in the components and risks delamination of the material’s layers, destroying the materials properties and leading scrap components.
Solution – Choose the right cutting tool and manage vibration
Choosing the right grade and geometry of cutting tools is essential for cost management. The grade determines the tool’s ability to withstand wear; the geometry determines how the cutter interacts with the material. Different cutting processes need the correct grade and geometry of cutting tools to be utilised.
High-grade cutting tools are needed to avoid excess heat, damage and inaccurate machining results. Polycrystalline diamond (PCD) tools are a common choice. These tools offer better abrasion resistance than carbide equivalents. PCD tools can also operate at triple the spindle speed and last up to 25 times longer than similar carbide alternatives.
Minimising vibration also plays a significant role in managing carbon fibre’s abrasive qualities. Vibration chafes the edge of cutting tools, shortening their lifespan. Blunt tools lead to heat buildup and the cost increases mentioned earlier.
The only way to prevent vibration is to use high-quality machines, like the ones supplied by Kingsbury – see the range here.
Challenge – Dust and hazardous working environments
Carbon fibre machining produces more dust compared to metal machining. This dust is harmful to the lungs and skin, and since it conducts electricity, it can also cause shorts in electrical equipment.
Solution – Wet Cutting
Cutting carbon fibre wet reduces airborne dust significantly, as most of the dust is carried away in the cutting liquid. However, this solution produces problems of its own. When cutting wet, the carbon fibre may be left with an oily residue, making final finishing processes a challenge. Carbon fibre can also be porous, meaning contaminants soak in. Cleaning processes add further expense to an already expensive material.
Solution – Cut dry and manage dust
Cutting dry avoids costly cleaning and potential damage, but this too has challenges.
Carbon Fibre creates hazardous dust during machining. Because of this, extraction should occur locally at the point of cutting, backed up by additional extraction from the machine enclosure. The machine enclosure needs a carefully managed airflow, to maximise the collection of airborne carbon fibre dust particles.
What can we learn?
The challenges and solutions discussed above are linked. Problem-free carbon fibre machining requires a suitable machine, the correct cutting methodology, a cooling strategy and careful dust management. Combining these factors reduces expenditure and time wastage, allowing you to deliver your product on time and within budget.
We at Kingsbury are experts in carbon fibre machining and can equip your business with the correct tools and procedures for success.
Get in touch with the team today if you’re ready to take advantage of these highly effective machining processes.