JEC COMPOSITES MAGAZINE - Issue #47 - March/April 2009 - 60

FEATURE “Automation” g…/… Radius-Pultrusion™ widens the borders of profile manufacturing conditions and the same potential as the conventional pultrusion process, with a few additional requirements (Fig. 2): - The production speed depends on the length of the mould. For standard polyester resins, the process speed is about 1 to 1.5 times the mould length. The possible dimensions depend on the machine’s dimensions and pulling force, i.e. in this case the pulling-pushing momentum. The existing machine provides for radii ranging from 300 to 1,000 mm and dimensions up to 100 x 200 mm, but there are no upper or lower limits to the process itself. - An additional boundary condition is the maximum length of the mould. For flat curves, the practical mould length is limited to approximately 45°- 90° of the full 360° circle. As a result, the production speed is limited for small radii. For example, a profile with a radius of 10 cm leads to a maximum mould length of approximately 8 cm and an expected maximum production speed of 16 cm/min using standard resin and curing systems. Common mould lengths from 0.5 to 1m can be applied for radii larger than 30 cm. - These boundary conditions do not apply to two-dimensional curves such as screw springs. Theoretically, the mould length can be as long as economically required. Practical limits are expected due to the forces caused by resin shrinkage. They are currently under evaluation. A maximum length from 180° to 360° seems feasible. Main features The Radius-Pultrusion™ process can be used to manufacture curved profiles with only a few limitations. Profiles with constant radii ranging from 350 to 1,000 mm and dimensions up to 100 x 200 mm can be produced on short notice. Both unidirectional and bidirectional reinforcement materials can be used. - Some precautions have to be taken when designing moulds for the manufacture of full circles. For a complete circle, the profile has to move over the mould during the production process. This is only possible if the torsion stiffness of the profile is not too high, so it can be guided without damaging the profile. For example, it would be easy to create bicycle rims but practically impossible to create car rims. Accordingly, the mould and the gripper must be designed as flat as possible for such applications in order to reduce the necessary torsion. The process is attractive not only for radii above 30 cm but also for smaller radii, as an alternative to a batch production process like filament winding. In most cases, the overall production speed of Radius-Pultrusion exceeds the speed of a batch process. Additionally, not only full but also hollow profiles with multiple chambers can be produced without core materials or silicone tubing, which is not possible in a batch process. Rocket and aircraft designers, building & construction engineers, architects, and furniture designers can now benefit from this process and use both curved and straight profiles for their projects. Spiral springs, arched windows and bridge arches, boat or aeroplane beams, or even half circles for the manufacture of lingerie are no longer a no-go. Contact: info@thomas-technik.com Fig. 2: Various profiles created with the Radius-Pultrusion process: (a) U-shape, carbon-reinforced, (b) U-shape, glass-reinforced, (c) hollow, glass-reinforced. More information: www.thomas-technik.com FREE SUBSCRIPTION (1 year/8 issues) Please complete the form on line: www.jeccomposites.com/magazine-subscription/ 26,583 copies total qualified circulation, BPA Worldwide, November-December issue 2008 60 jec composites magazine / No47 March-April 2009

http://www.thomas-technik.com http://www.jeccomposites.com/magazine-subscription/

JEC COMPOSITES MAGAZINE - Issue #47 - March/April 2009

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #47 - March/April 2009