Another main use of copper nuts is injection moulding. After heating, they are embedded in plastic parts or directly moulded. As mentioned earlier, brass has good thermal conductivity. For example, when copper nuts are embedded after heating, on the one hand, copper nuts can quickly heat up and speed up work efficiency, on the other hand, copper nuts after heating can quickly. By conducting heat to plastic parts, the periphery of plastic holes becomes soft, which is conducive to pressing into the holes; then, what is the effect of injection moulding? As we all know, the melting point of PA/NYLOY/PET is above 200 C. The temperature of copper nut increases rapidly when it is melted into plastic parts. After injection moulding, the plastic body cools rapidly and crystallizes and hardens. If the temperature of copper nut is still high, what will be the result? Clever you must have guessed, the result is that the place where the copper nut contacts the plastic parts is loosened or cracked. So copper nuts are used in injection moulding instead of steel nuts.

The shape of copper nuts used in injection moulding is generally circular with various patterns. The hot melting of the mould is usually cylindrical (as shown below). The shape of copper nuts used in hot or cold pressing has a certain taper or inverted spine (as shown above on the right). As for why it is conical or inverted spine, you can guess wisely.