JEC COMPOSITES MAGAZINE - Issue #44 - October 2008 - Special Asia - 68

USERS’ PLATFORM Application Large structural thermoplastic composite panels Continuous-fibre thermoplastic (CFTP) composites have several advantages in comparison with thermoset composites. However, the industry has not been using them on a large scale so far, mainly due to manufacturing difficulties. AS Composite has developed an innovative production system capable of mass producing large thermoplastic composite panels. Equipment The AS sandwich panel is manufactured by a machine that was developed by AS Composite’s engineering department in close cooperation with the National Research Council of Canada (NRC). They decided to create a new machine to overcome the restrictions inherent to the machines and presses currently available on the market, namely manufactured panel dimensions, fabrication time, mould heating and significant energy and raw material loss. The process offers several advantages: • Easy production of large parts − panel length is no longer limited by the press length. • Production of parts with different types of surface finish − the machine easily tolerates additional thin films on the surface of the finished product. These films can be used to improve properties such as colouring, joining, paint adhesion, fire resistance, and more. • Manufacturing rate of 1.8 m/minute for a panel up to 2.4 m wide. • Panel thickness ranging from 5 to 150 mm with 0.5 to 3 mm-thick skins. • The profiles can be roll-formed after consolidation using forming rollers. A pre-heated reinforced TP laminate passes through a series of compaction rollers and is transformed into a partially consolidated flat strip. Instead of being laminated with a core material to make a sandwich panel, the flat strip then continues passing through pairs of forming rollers and, finally, the desired profiles (V, L, U, etc. shape) of continuous fibre thermoplastic composites exit at the end of the process. The most critical aspects of the process are: • Defining optimum parameters (window Process) including the roller speed, the temperature and pressure applied at each nanufacturing stage. • Thermoplastic laminate heating speed. The centre of the laminate should reach the required temperature without surface degradation. • Surface temperature of the skin and core, that must fuse together without crushing the honeycomb core. • Temperature of the consolidation rollers to ensure gradual cooling and avoid significant temperature variations in the laminate thickness. GOLNAZ SHOKOUHI, ENGINEERING MANAGER, AS COMPOSITE FTP materials can be formed into any shape using only a combination of heat and pressure. Hence, they are much easier and safer to process because they do not produce any harmful emissions, and are therefore environmentally friendly. Moreover, unlike traditional thermoset composites, thermoplastics can be reheated and reused a number of times, and they are easy to recycle. However, their industrial development is hampered by a number of manufacturing difficulties. Only press machines can simultaneously apply high temperature to melt the matrix and high pressure to consolidate the material. These low-rate machines produce limited volumes of small- to medium-sized parts, which is not cost-effective for thermoplastic products. The system developed by AS Composite consists in roll forming the raw material using both heat and pressure in a continuous manner. The main product is the ASC panel, a sandwich panel made of thermoplastic composite skins covering a core panel. The core is a lightweight material such as honeycomb or foam, which is mainly used to provide the required panel thickness, strength and stiffness. Applications The main business development opportunities for ASC panels are found in the construction industry. - Concrete formwork The annual market for concrete formwork in Canada and the USA is estimated at 400 million dollars. The use of conventional plywood or steel panels is limited due to the inconvenience of these materials in concrete formwork. Thermoplastic composite panels with PP honeycomb core can favourably replace the current formwork with no changes JEC Composites Magazine / No44 October 2008

JEC COMPOSITES MAGAZINE - Issue #44 - October 2008 - Special Asia

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