A growing environmental problem – created by the effect of human activities on the quality of our atmosphere – and the increasing scarcity of non-renewable resources are heavily modifying our habits. “Energy efficiency” and “reduction of carbon emissions” have become mantras for any type of human activity. Weight reduction, smart design of parts, use of renewable resources and more economic production methods have been perceived as the easiest approach to the solution of this widespread problem.
Characterized by light weight, good mechanical performances, relatively low level of energy required for their process, CFRP (Carbon Fiber Reinforced Plastics) are progressively replacing conventional materials – such as stamped metals or conventional reinforced plastics – for the manufacture of thousands of “things” that can replace heavier components which contribute to consume energy or natural resources during their lifetime. Stimulated by the increasing competitiveness of these modern composites numerous producers have since many years oriented their manufacturing strategy toward CFRP technologies.
Composite production: a multi-step process
One major bottleneck in the manufacture of CFRP parts is still represented by the high number of operations required to produce a single piece in composite materials. After nearly a century of industrial manufacture of injection-molded pieces, where with a single operation a finished part is extracted from a mold, it is quite hard to return to a semi-manual method of assembly, at least for the largest parts. But, by definition, a piece of composite is made with a reinforcing support impregnated with a polymeric resin. Superior performances, in terms of cycle time and resin distribution, are obtained using fluid liquid formulations reacting in the mold throughout a textile-like support, rather than injecting in it a plasticized polymer. This “delicate marriage” requires a sequence of operations that generates rather long cycle times and a costly manpower.
To optimize this complex production sequence, a number of technological improvements had to be developed and industrially implemented. End users, suppliers of equipment and of chemical formulations worked hard for several years to analyze the problems of the process and find the most convenient alternatives.
This article appeared in the Sept/Oct issue of Reinforced Plastics.