What made this a particular challenge was not only the sheer thickness of the finished product, which meant the raw material stack would be even thicker, but the skill required to ensure it was cured all the way through. “We quickly established that we would actually be able to get the 330mm stack of impregnated sheets into the daylight of the press in the first place,” said technical development engineer, Matt D’Arcy. “So our attention then turned to ensuring the heat penetration was adequate all the way through the stack without overcooking - epoxies can be at risk of something called thermal runaway if you're not careful.” Having embedded a thermocouple in the middle of the stack to monitor the core of the laminate, the press was brought slowly up to temperature and held. The stack was covered in tin foil to keep the temperature in and to help the heat penetrate. “We used the same technique as if we had been baking a giant cake,” explained D’Arcy. “The thermocouple confirmed we had the correct temperature penetration and because we'd taken into account the cutting pattern, we made sure the metal was in one of the offcuts.” www.attwater.com
