Morning grouch vs. party volcano
At low temperatures, plastics are stiff and sluggish - like a person shortly after waking up and without coffee. As the temperature rises, movement comes into play - the party can soon begin.
The plastic granules melt inside the heated injection moulding cylinder and become increasingly mobile due to the rotary movement of the screw, where they are mixed together to form a homogeneous mass. The result is a hot, almost lava-like melt that finally wants to be released onto the party. The initially viscous, hot plastic is forced through narrow channels into the mould cavity during injection moulding - the volcanic flow moves very quickly, but comes to a halt just as suddenly in the cold cavity. Once there, the rapidly cooling mass flow leans against the mould wall, rests there for a while and becomes increasingly stiff and sluggish. The party is over when he is thrown out.
Rheology is therefore concerned with plastic compounds that become flowable under the influence of thermal energy. Thixotropy the simply explained terminology of the last newsletter, describes a change in the flowability of other masses, which are only due to the influence of movement.