Manufacturing of composites is one the most important aspect in the composite applications. Ideally, composite manufacturing involved the mixing of reinforcement materials with matrix material, and there are variety of fabrication methods to produce diverse structural applications. However, before going into its details, we should look into the traditional metal manufacturing technology.
Traditional Metal manufacturing v/s Composite Manufacturing
Metal manufacturing technology for structural applications is relatively well matured. In metals, the material fabrication and structure fabrication are two separate processes. Firstly, the finished form such as rods, slabs, or sheets of metals are fabricated. Further working is then carried out on these finished forms of metals to fabricate the final products. Metal manufacturing of structures usually involve complex tooling and complicated assembly procedures.
On the contrary, in the composite manufacturing the fiber and matrix constituents are usually transformed in the finished products directly, thus, bypassing the intermediate working needed in case of metal manufacturing. To elaborate more, let us make a comparison of a pressure vessel made from metals and from composites as shown in Figure 1.
Figure 1. Metal manufacturing vs composites manufacturing technologies
The manufacturing of metallic pressure vessel begins with the finish sheet forms of metal. These sheets are then go through various cold or hot forming processes e.g. cutting, stretching, bending, pressing or welding etc. performed in a sequence. Each forming process requires dedicated equipment. The dome parts and cylindrical part of vessels are fabricated initially, then, are joined together to build up complete pressure vessel. Moreover, the amount of energy required to transform finished materials to final product is significant high.
On the other hand, in composite manufacturing the constituent matrix and fiber materials are directly transformed into the final product. The wetted fibers with resin matrix with relatively simple equipment are wound on a mandrel to make pressure vessel in just a single step. Consequently, the number of parts and processing steps in case of composite manufacturing can be reduced. Moreover, the amount of energy required to produce composite product is relatively low. This was one way to looking at the composite manufacturing where everything seems perfect, but, sadly it is not. The other side of picture is that the composite manufacturing requires relatively skilled manpower. The automation and standardization of manufacturing processes are limited. There is need of more stringent and reliable quality checks for composite products having inherent material anisotropy and inhomogeneity. More sophisticated nondestructive techniques are require to monitor the health of composite structures in service. The repairing of damaged composite products is also challenging.
Future of Composite Manufacturing Technology
Let’s me draw a complete picture for you. The life cycle cost for composites, in general, is relatively low, considering its weight reduction potential, requirement of lower number of equipment, number of parts and steps involved in manufacturing and assembly. However, the costs of raw materials i.e. fiber and matrix, used in manufacturing is still high in a comparison to metal counterpart. The role of composites was previous limited to the advanced aerospace applications where it justified itself owing to weight savings mainly. But, its current status and future prospects are looking very promising. The technology is rapidly paving its way to all other areas like automotive, robotics and sports. Recently, there is a trend of decreasing cost of the raw materials due to improved manufacturing techniques and process automation, increased competition among the manufacturers and suppliers and overall growth of the composite market. The time has come when the composites products are begin to challenge the long-lasting hegemony of their metal counter parts in terms of light weight, superior performance, enhanced customer satisfaction and competitive cost.
About the Author:
Dr. Khazar Hayat is a professional engineer with almost 15+ year of experience in research, design, analysis and development of products made of fiber reinforced plastics composites (FRPCs). Currently, he is working as an Associate Professor at Mechanical Engineering Department, The University of Lahore, Pakistan, and can be reached by emailing at khazarhayat@gmail.com.
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