The bearable lightness of the GDP

It is a non-metallic element, tetravalent and unique in its chemical properties because it can create a number of compounds that is greater than the total number of all the compounds that all the other elements can make by combining with each other. No other element is as important to life, because only carbon forms single, strong bonds with itself, and these are stable enough to resist chemical attacks under environmental conditions. This gives carbon the capability of supplying long chains and rings of atoms that constitute the structural basis of many compounds that include living cells, the most important of which is DNA.

The Perini Journal meets the research team of the Divisione Carbonio (Carbon Division) of Fabio Perini S.p.A. Daniele Del Carlo, Head of Production, Tiziano Fracassi, engineer in charge of Technical Supervision, and Fabrizio Raffaelli, engineer and Chief Technologist of the INFN (Istituto Nazionale di Fisica Nucleare – National Institute of Nuclear Physics) of Pisa, who has been collaborating with Fabio Perini SpA for some years, introduce us to the world of carbon and composite materials and speak to us about their applications in the world of tissue.

Perini Journal

“The production mass has remained substantially unchanged with respect to a century ago, while the actual value of the GDP in the same period has increased 20-fold. This means that the weight per unit of value has substantially decreased.” This statement made by Alan Greenspan, then governor of the Fed, in 1996 at the Conference Board in New York, highlighted a phenomenon that began in the 1950s with the widespread adoption of plastics for the production of consumer goods, and had witnessed a strong acceleration in the 1990s with the development of information and telecommunications technology.

WITH THE ADVENT OF NET ECONOMY,

WE BEGIN TO FANTASIZE ABOUT THE “DEMATERIALIZATION” OF PRODUCTION.

The phenomenon has interesting repercussions in terms of ecology and sustainability: producing the same goods using fewer resources and energy means, impoverishing the planet’s resources to a lesser degree, but also creating new opportunities for companies. Today, with oil prices increasing daily and alternative energy sources absorbing more investments in research than profit yields, sustainability and energy efficiency are priorities not only for environmentalists but also for entrepreneurs and managers, aware that today, a competitive advantage can be gained also by reducing energy costs.

MORE PRODUCTIVITY AND ENERGY EFFICIENCY ARE TWO FUNDAMENTAL AIMS FOR ANY COMPANY THAT TODAY WISHES TO CONQUER OR MAINTAIN A COMPETITIVE ADVANTAGE. But they may seem in contrast with each other. We are just issuing out of an era of available, low-cost energy, and are heading towards a period in which it will be necessary to consider energy as a problem rather than as a given fact. And this is true both for those who work in the industrialized world, where energy supply will be increasingly more expensive, as well as for emerging countries, where the problem is – and will continue to be – the reliability of energy supply. The two objectives seem to be in contrast with each other because, up to now, progress in the fields of productivity in agriculture, industry and services has been attained thanks to highly energy-intensive innovations: synthesized fertilizers, automation, the development of information and telecommunications technology are fruit of the intensive exploitation of hydrocarbons as materials or as fuels.

THE SOLUTION TO THIS APPARENT CONTRADICTION CAN BE RESEARCHED, AT LEAST IN PART, IN MATERIAL SCIENCE AND IN PARTICULAR, IN COMPOUNDS. “These are materials not present in nature and are a result of the combination of at least two components in different form, proportion, distribution and orientation.

The proper combination of two elements produces a material that has new mechanical properties and thus yields better performance for the required operational conditions than would the single components on their own. Each constituent maintains its own identity in the resulting compound without dissolving or completely fusing into the other,” explains Fabrizio Raffaelli, engineer and Chief Technologist of the INFN (Istituto Nazionale di Fisica Nucleare – National Institute of Nuclear Physics) of Pisa.

THE FREEDOM THAT COMPOSITE MATERIALS OFFER the design engineer is to be able to optimize the material for the loads to which it is subjected, obtaining the desired response to thermal and mechanical loads. This objective can be reached using different materials in different spatial orientations within the structures. One example is the use of low-density cellular material (Rohacell, termanto, polyurethane foam, etc., that have a density 50-60 times lower than that of aluminum) coupled with advanced composites. Steel and concrete is another example: the iron rod supports tension loads, while the cement supports compression loads. Hence, to optimize its use, the design engineer will concentrate the steel in the area where traction is present. At a greater sophisticated level, composite materials consist in a high resistance long fiber inserted in an epoxy matrix. The result is a savings in weight obtained thanks to the enhanced weight-resistance ratio. Other advantages with respect to traditional materials include high resistance to corrosion and resistance to fatigue.

MOST MODERN COMPOSITE MATERIALS COMBINE A THERMO-SETTING RESIN MATRIX WITH LONG FIBER REINFORCEMENTS.

The most commonly used reinforcements are carbon and aramid fibers. The choice of reinforcement type and resin quantity allows calipering the features of inertia and resistance on any finished product requirement. Today, composite materials are used to make all kinds of products: from tennis rackets to golf clubs, from skis to the soles of shoes and boots, from auto and motorcycle bodies to plane cockpits, from satellites to bicycle chases.

THEIR USE IN THE PRODUCTION OF MACHINE TOOLS IS NOT YET WIDESPREAD. Why? First, because of costs. But also the idea that they are extremely specialized materials, still subject to problems of reliability, appropriate for experimental applications. As we will see, many of these doubts are founded more on myth than on fact: production processes are nowadays reliable and safe, and design is integrating these components in machines presently found on the market. And this is true also for tissue converting systems. ”At Fabio Perini SpA, the research on composite materials began in 1995 with the XXL project: the size of the machine itself (5500 mm in width) imposed – due to the necessity to limit weight – the need to find innovative materials that could guarantee the same rigidity as steel with a lower material density (and hence a lesser weight),” states Daniele Del Carlo, Responsible for the Production Area of the Carbon Division - Divisione Carbonio. At the beginning, Fabio Perini SpA turned to external suppliers. But the awareness of how strategic it may be, in the future, to have a specific know-how in the field, three years ago suggested to the company to begin production of carbon kinematic systems.

“THIS CHOICE WAS DICTATED ALSO BY SAVINGS AND RISK REDUCTION LOGISTIC ASPECTS,” CONTINUES DEL CARLO.

“The production of objects using composite materials is often tied to artisan proceedings that do not allow a guarantee of the uniformity of the product to the requested characteristics. The choice by Fabio Perini S.p.A. was thus oriented towards the development of proven, effective production technology and industrial features that have numeric control as support in order to manufacture rolls having uniform characteristics, even if speaking about large quantities.”

The production technology adopted at Fabio Perini S.p.A. is filament winding, and consists in the controlled and automated deposition of composite material around a rotating mandrel, shaped according to the desired geometry of the finished product. The characteristics of the finished product are determined by the orientation of the fibers (under software control), by the material used (that may be pre-impregnated or impregnated during the process) and by fiber tension. This technique guarantees high productivity, precision in fiber positioning and in the control of the quantity of resin that can be changed during the production process, minimizes human intervention and allows doing away with the autoclave for resin polymerization.

SINCE 2006, ABOUT 2000 ROLLS IN COMPOSITE MATERIAL HAVE BEEN PRODUCED, mainly used as idle rolls which, in order to perform their task, need to sustain negligible solicitations during system operation. But experimentation does not stop here. We are already speaking about embossing rolls made in composite material and, above all, we are starting to consider a tissue converting system completely redesigned to exploit the features of composites to the fullest. The objective? “We can envision, for the future, to exploit all the benefits that composite material, with its functional specialization, can offer us,” explains Tiziano Fracassi, engineer in charge of Technical Supervision of the Divisione Carbonio of Fabio Perini S.p.A. Some examples? “Smaller rolls allow building more compact machines that can be housed in smaller spaces, with the consequent investment reduction in workshop space or a reduction in space rental and management costs. And also, smaller and lighter rolls reduce solicitations on the machine’s structure and can allow reducing its size and weight. Lighter machines entail lesser costs and transport times, assembly, installations and trials, with a reduction in the time between purchase and start of production of the system.

In this case, the benefit is not only a financial one, but also operational.” But, if it is evident that the integral redesign of a system can be just a medium-term objective, we cannot imagine that experimentation does not proceed along smaller cabotage pathways, looking for immediate economic and technological benefits.