JEC COMPOSITES MAGAZINE - Issue #58 - June - July 2010 - 62

KNOW-HOW
Induction

New process for high-temperature carbon fibre moulding
Start-up company RocTool has earned a reputation for its Cage System® process. Now RocTool is introducing its new complementary 3iTech® technology, a new family of induction heating processes with inductors integrated into the mould. While the Cage System® is known for rapid heating of the tooling surface, 3iTech Integrated Internal Induction Technologies opens up other possibilities for processing composite materials, because it enables processing thermoset or thermoplastic materials at temperatures from 20°C to 400°C, including carbon fibre.
simply as a 3D network of “super” cartridge heaters with the following features:
FOUNDER

JOSÉ FEIGENBLUM, R&D MANAGER & ALEX GUICHARD, & CEO ROC TOOL

W

ith this new Heat and Cool process, RocTool’s philosophy remains focused on two non-dissociable parameters: - electromagnetic induction to heat the mould quickly, - controlled localized heat. In 2001, when RocTool started pioneering Heat & Cool technologies, it was somewhat alone in its corner, trying to convince the plastic and composite sector of the advantages of heating and then cooling a mould to process materials. Then, around 2007-2008, the sector made an about-face, and now, most of the major resin and equipment manufacturers in the main segments have either R&D or qualification programmes in progress on Heat & Cool technologies. RocTool didn’t opt directly for electromagnetic induction. The company had previously tested a number of alternatives, including Joule-effect, high-frequency and microwave heating methods. Induction is the safest and most effective industrial solution to heat up tooling rapidly, compared other known technologies, such as pressurized heat transfer fluids (water, oil, steam) or cartridge heaters. Induction can be used to heat up a mould in two different ways: - Cage System® - External induction heating coil with direct heating of the tooling surface, - 3iTech® - Internal induction heating coil with heating of a steel sub-layer underneath the mould surface (Fig. 1). The 3iTech® process uses inductors that are integrated into the mould to heat the mould surface by conduction. It can be defined

1) the inductor network: − is 3D compatible; − can extend over considerable lengths (up to several m²); − can transmit high levels of power (up to several hundred kW); − can function at high temperatures (up to 400°C and more);

Fig.1: 3iTech® mould representation for thermocompression

2) the cavity’s thermal resistance is zero because the energy is applied directly through induction over the surface of the cavities that surround the inductor network. Controlling the induction process allows injecting high levels of power (20 to 30 W/cm²) over very thin layers of metal (usually several tenths of a millimetre) to activate rapid, controlled temperature rises while limiting any inertia effects.

Description of 3iTech and its variants
The basic principle for 3iTech® relies on creating a network of cavities with integrated induction heating coil (Fig. 2). The use of induction to heat up the cavity surface makes it possible to achieve a homogeneous rise in temperature all over the tooling surface and to optimize the heating time and energy required. The distance between the cavity and the moulding surface,

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jec composites magazine / No58 June - July 2010
JEC COMPOSITES MAGAZINE - Issue #58 - June - July 2010

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #58 - June - July 2010
