Did you know that in many cases, comparisons with nature and humans can be used to explain facts in plastics technology?
Today's term: The plastic soul - the liquid core under the skin
Cherry tomatoes on pizza should be enjoyed with caution. Even if the pizza seems to have cooled down a little, you can still burn your tongue on the lava-like centre of the cherry tomato.
A plastic moulded part that has just been demoulded behaves in a very similar way. There is still residual heat under the cooled skin of the moulded part, which is more or less pronounced depending on the dwell time in the cooled mould and would like to reach the cold surface of the part. At first you can still touch the part that has just been demoulded, but just a few seconds later the plastic part is already so hot that you could burn your sensitive fingertips - hence the white cloth gloves worn by the workers on the SG machines.
Despite everything, the plastic core is a good thing. This is because the hot core, which persists everywhere in the middle of the wall thickness and especially at the thickest point of the moulded part, makes it possible for the moulded part to be filled with plastic immediately after injection of the hot plastic compound. Reprint can be completely filled. However, once the area around the injection point has cooled down, a plastic core under the thickest part of the moulded part will only cause undesirable effects - sink marks and the risk of part distortion - if the mould is removed prematurely apart from the fact that you can also burn your fingers.