Some of these can cause deformation of the injection moulded part due to improper selection of the core extraction mechanism and the mould exit organisation. Injection mould processing and manufacturing takes into account the fact that there are dozens of traces in the moulding process which are defective traces and are not allowed to exist on their own. These traces possess not only surface visible traces, but also essential microscopic traces such as looseness, air bubbles and residual stresses in the injection moulded part. In particular, for some defects caused by elements of the mould structure, they must be removed when determining the mould structure solution. However, for defects that are not caused by the mould structure, we can find out the reasons for their formation through mould trials and then apply appropriate countermeasures to eliminate them. There is an increasing demand for the aesthetics of the external surface of the injection moulded part, which is known as the appearance element of the injection moulded part. When designing the structure of an injection mould, the influence of the appearance of the injection moulded part on the structural solution of the mould cannot be ignored. To use a common phrase, the appearance element of an injection moulded part is to ensure that the external surface of the injection moulded part is free of traces of the mould structure. However, traces of the gate, traces of the mould parting surface and traces of the mould exit are indispensable, especially the first two. Appropriate measures should therefore be taken to prevent the appearance of these marks.