What are composite materials? Definition and examples

WHAT ARE COMPOSITE MATERIALS? ALL YOU NEED TO KNOWAlthough one thinks of composites as latest generation materials, their emergence is due to the effort of men in ancient times to invent solutions that improved their quality of life. Consider, for example, bricks of clay and straw, rather than alloys such as bronze.

In modern times, we return to talk about composite materials with the introduction of the first phenolic resins reinforced with asbestos dating back to the early 20th century, followed by the first fibreglass boat in 1942, the introduction of the first high-strength boron and carbon fibres from the early 1960s, and the development in 1973 of aramid fibres by Dupont etc.

Since the late 1970s, technological investments in the aeronautics and automotive sectors gave new impetus to the progress of composite materials which, thanks to the emergence of new materials and the use of more sophisticated manufacturing technologies, gradually guaranteed ever increasing performance.

What is a composite material?

By definition it is a material consisting of the union of two or more distinct materials:

  • Fibres
  • Matrices
  • Additives

The idea behind composites is to "unite the forces" of materials with different characteristics that, taken individually, do not provide any particular performance.

The development of modern composite materials owes its growth to the ever-increasing demands of various sectors, starting with Aerospace and Aeronautics, and then moving on to Sport, Biomechanics and Furniture.

Among the most innovative composite materials currently on the market are:

  • Organic matrix composites (for example, laminated materials and reinforced plastics)
  • Mineral matrix composites (for example, concrete and ceramic composites)
  • Metal matrix composites (composed for example of Al/Carbon fibres)
  • Alloys (for example, steels, Al alloys, brasses).

The main components of organic matrix composite materials are the matrix and the fibres.

The matrices are essentially:

  • Epoxy resins
  • Polyurethane resins
  • Polyamide resins
  • Phenolic resins.

The most used fibres are:

  • Fibreglass
  • Carbon fibre
  • Aramid fibres (kevlar)
  • Ceramic fibres.

The matrix and fibre combination gives rise to a material with extremely high mechanical characteristics and a decidedly low density. This last aspect is by far secondary: the decrease in the characteristic dimensions implies an improvement in mechanical performance and a decrease in the probability of finding significant defects in small bodies. The use of fibres is justified by the fact that many materials are more resistant in this form.



The advantages of composite materials

It is known that the costs of composite materials are on average higher than those of conventional materials, especially for those with long fibres (in which the fibres are arranged in an orderly manner and oriented in an isotropic matrix). Despite this, companies have started using them with increasing frequency due to the different advantages they offer:

  • Lightness
  • Strength
  • Rigidity
  • High resistance
  • Design versatility (for sandwich and laminated materials)
  • Reduction of manufacturing costs
  • Weight reduction

In the furnishing and design sector, for example, composite materials are used with a thermosetting resin matrix, which generally includes polyester, epoxy, vinyl and phenol ester, and carbon fibre or glass fibre reinforcement. This type of composite materials, in addition to possessing the characteristics listed above, are distinguished by being:

  • Fireproof
  • Antistatic or with high electrical conductivity
  • Pigmented or translucent
  • Resistant to abrasion

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Composite materials and the wood industry

The woodworking industry is a market characterized by high technological content to meet the increasingly high demands of end users. For this reason, the processing of innovative materials such as no-wood materials and, precisely, composite materials is very common among furniture manufacturers. In a recent survey, preparatory to the Ligna 2019 fair in Hannover, it emerged that 51% of the furniture manufacturers interviewed are by now familiar with plastics, panels, insulating and building materials and also with composites.

The demand for more and more personalized furniture and furnishing accessories requires the use of much more versatile and flexible materials that enable planners and designers to create products in line with current fashion, without encountering the limits of the materials available. This means that the designs must be suitable for the manufacturing process of the new material, in order to respect manufacturing constraints. For this reason, replacing wood with composite materials in some categories of furniture or furnishing products requires a total redesign especially in the structural parts.

This trend, linked to the use of composite materials, also directs the research and development of woodworking tool suppliers since, given the characteristics we have mentioned, this type of material often presents critical processing issues, being very abrasive.



How are composite materials processed for the furniture industry and furnishing accessories?

For the processing of composite materials, dedicated tools are required, very resistant to wear and with long cutting edge retention. Polycrystalline diamond (PCD) tools, for example, especially those with solid tungsten carbide bodies, give excellent results on the final cutting quality for the processing of this type of material, giving the finished product an excellent surface finish.

In the furniture and furnishings sector, Wirutex hi-tech tools is a reference point in the development of PCD and tungsten carbide tools with a high technological content that are well suited to the modern needs of furniture manufacturers. We recommend reading our in-depth study “Composite materials and the wood industry: THE CHALLENGE OF THE FUTURE” where you can obtain further information concerning this sector.


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By Editorial staff |
20 September, 2019