Cannon Group R&D improves precise composite mold temperature control

Nexus composite mold with integrated heating elements for highly precise and energy-efficient temperature control. Source | The Cannon Group

The Cannon Group’s (Caronno Pertusella, Italy) Nexus system, comprising a composite mold, thermoregulation system and associated controls, is 25% more efficient in regulating mold temperatures compared to standard mold heating practices. In addition, the system opens up additional optimization scenarios previously and reduced cycle times. The Group’s goal with this innovation? Increasing part quality and potentially cutting raw material use for polyurethane (PU) reaction injection molding (RIM) manufacturing, though it is applicable to other processes that involve thermoset materials.

Nexus uses the physical properties of composites not only as structural reinforcement, but as heating elements integrated into the mold itself. This allows for very fast temperature ramp-ups, Cannon Group reports, up to 30°C/minute, as well as more precise localized temperature control compared to fluid-based systems. Within the mold, this makes it possible to create differentiated thermal areas, separated by gradients less than a few millimeters.

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This feature is particularly useful in processes where the material’s chemical kinetics have to be carefully modulated. The nature of composites also offers the possibility of designing the mold with “tailor-made” properties, calibrating the heating rate, transverse conductivity or heat distribution according to the requirements of the part to be produced.

“In thermoset molding, heat management is a crucial factor in achieving consistent quality, competitive cycle times and energy-sustainable processes,” says Andrea Castelnovo, technology and R&D manager at Cannon Tipos. “Traditional technologies, based on metal tools and thermal fluids, have reached a physiological limit. Even when optimized, they rarely exceed 75% energy efficiency and impose thermal inertia that affects the entire production process. These considerations led to the creation of Nexus. The goal was simple in theory but revolutionary in practice: to heat only what is needed, in the shortest possible time, thus minimizing energy waste and dispersion.”

Developing the Nexus system required more than 10 years of experimentation, with the aim of improving efficiency for RIM and high-pressure resin transfer molding (HP-RTM). As literature on using composites as heating elements was limited, Cannon conducted a series of internal electrical and thermal tests to fully understand their behavior. Based on the data collected, a mathematical model was built to simulate an operational composite mold with integrated heating.

Even before the first Nexus prototype was built, composite plates had been produced using the same principle, which enabled the company to compare simulation and reality, optimize the heater layout and define the correct material sequence. The next step was to build a demonstration mold designed to replicate the operating conditions of a RIM process for PU foams. Field tests then confirmed the theoretical results: the quality of the parts produced was equivalent to that obtained by more established technologies, while energy consumption was reduced by more than 70%. Furthermore, the time needed to bring the mold temperature up was drastically reduced, from about 1 hour to around 8 minutes.

Nexus is aligned with Sustainable Development Goal 12 for Responsible Consumption and Production, giving manufacturers the ability to precisely regulate temperatures in order to maximize material expansion and reaction performance. It reduces raw material use and cycle times, while eliminating hazardous thermal fluids from the process; this, in turn, simplifies the plant’s overall energy infrastructure by removing the need for complicated heating and piping.