Why is Cross-Contamination a Problem?
Carbon Fibre (CF) and Kevlar are some of the advanced composites used for the fabrication of many critical components in medical instruments, aerospace, motorsports and other areas which require tightly controlled parameters. Within the family of Carbon Fibre, different resins can be used along with various other fibre reinforcements such as natural flax. Each component affects the final composite, delivering the overall performance required for the product’s end use. It’s therefore important that the composite is not contaminated by undesired fibres during handling and construction.
Manufacturers working with Carbon Fibres, particularly those in the medical or advanced research fields take great care to avoid contamination of their composite materials to prevent failures or undesired properties in the finished composite product.
An oft-overlooked source of contamination is the workbench surface itself; table tops made from any fibrous material such as MDF, hardboard, or timber will produce dust when tools and materials move against the surface. These wood fibres and the resins in engineered wood-based surfaces can easily work their way into CF cloth, becoming entrapped and altering the composition of the final layered up product.
Preventing Cross-Contamination
Due to the micro size and shape of carbon fibres, they tend to become embedded into the tools used and surfaces they are being worked on. To prevent cross-contamination from one type of fibre to another, PPE should be changed between jobs and the surface meticulously cleaned down, particularly after cutting or sanding. Tools such as cutting instruments, sanding blocks etc that have come into contact with one composite type should be kept for that material only in order to prevent fibre cross-contamination.
The Role of the Work Surface
Changing tools is one thing, but often a workstation will need to handle multi-types of material. This makes it critical that the work surface is easily cleanable, non-static and scratch-free as any surface imperfections will become hosts for trapped fibres.
Rhino supply a number of specialist worksurface mats, the best for working with carbon fibre being the Rhino Ultra-Seal, followed very closely by the Rhino Heavy-Duty Cutting Mat. Both these bench mats have exceptional self-healing properties, meaning that the surface remains smooth, with no scratches to trap fibres. The Ultra-Seal has the hardest surface (70 shore) of all cutting mats, so is ideal for frequent use of heavy-duty knives that are often used when working with carbon fibre and Kevlar.
Both the Heavy-Duty and the Ultra-Seal mats are thicker than standard cutting mats and are single-layer, making them very durable. Their smooth surface doesn’t attract dust and is easy to wipe down, making it ideal for carbon fibre and other composite material working. When cutting CF cloth against the surface, a cutting mat ‘holds’ the blade which reduces the risk of slipping offline.
A single-layer, extra thick mat made from tougher material massively reduces the chance of contamination from mat silvers or bits of the actual mat breaking down, even after a lot of heavy cutting work. These high-performance cutting mats will last much longer than standard 3-layered craft cutting mats, which can begin to delaminate or break down when used extensively in an intense industrial field.
Rhino supply the largest cutting mats to suit many sizes of workbench, or can even make them to order to fit your worksurface in one, uninterrupted piece.
Recommended Surface Protection and Cutting Mats for Composite Material Fabricators:
Ultra-Seal Cutting Mat 6mm thick with a shore hardness of 70, allowing the heaviest knives to glide through without damage. Smooth, phthalate plasticiser-free finish, for working with sensitive materials.
Rhino Heavy-Duty Mat 4.5mm semi-opaque cutting surface with a slight texture is great for precision hand cutting of CF cloth. With a shore hardness of 50, this is the best mat for working with impact sensitive equipment or more fragile materials.
