Material costs can be broken down into five areas: fibres, resins, consumable materials, labour costs and machine costs. The major cost is typically the fibre element, either as fibre off the spool or in woven or stitched format.
Fibre cost trends
There are a number of variants within each material that affect the overall cost. Generally the mechanical properties and environmental resistance, particularly temperature resistance, increase with increasing cost.
The range of prices for different fibre types is explained by variations in quality, and therefore strength and durability, of the fibre, and the costs for the different types of surface treatment which are applied to improve the bonding of the reinforcement to the resin.
The resin is the key controllable item that can reduce the other costs. Though not the single major cost, the chemistry and processability of the resin is critical. For example, prepregs and wet / dry lay-up materials can be cured at ambient temperature (or little higher), made possible by tailored resin formulations. The resin also affects the costs involved in wet-out of fibre mats, room temperature out-life, frozen storage life and good handling for laminating by hand.
Generally the mechanical properties and environmental resistance, particularly temperature resistance, increase with increasing cost.
Consumables vary depending on the material processing and lay-up methods. They do not form a major part of the overall costs and cost trends would need to be identified for specific applications.
Labour and machine costs
These are intertwined. For example, as the impregnated weights of prepregs increase, the machine run speeds decrease but then the labour costs reduce since the process tolerances are better catered for by machine design. Specialist motor racing and aerospace laminators are charged at far higher rates than construction labour gangs, since the construction market cannot tolerate such high labour costs. However, this is overcome by specialist training by material suppliers and the creation of lists of approved installation contractors for tendering purposes.
It is impossible to give a single comparison of composite costs and traditional material costs (eg. steel) because suppliers use discretion on a job-by-job basis and the prices of raw materials are frequently updated to reflect advances in material processing technology. The range of composite / steel cost ratios usually spans between 5 and 10, but the final delivered product is often no more expensive than, say, steel alternatives. This is due to easier installation of lighter composite components and far lower whole-life maintenance costs. It is recommended that supply chain managers of projects be consulted directly for the initial capital outlay and whole-life cost implications of using composites.
Additionally, there may be a number of indirect costs, such as quality control, health and safety considerations, etc. which need to be taken into account. Also, there is an increasing emphasis on environmental factors including maintenance, recycling, and disposal, which, over the lifetime of a component, can be important. For many components, the benefits from the use of reinforced polymer composites can become very significant when whole-life costs, rather than just fabrication costs, are included.