The parting surface of a mould are those surfaces of both mould plates adjacent to the impressions which butt together to form a seal and prevent the loss of plastic material from the impression.

The various factors to be considered while selecting the parting surface are:

Shape of the Components.

Type of Mould.

Method of Ejection.

Method of Manufacture.

Location and Type of Gate.

Aesthetics of moulding.

In general the parting surface is classified as,

Flat parting surface.

Non-flat parting surface.

Flat parting surface

Parting surface having only one plane is termed as Flat parting surface. The position of the parting surface will therefore be at the top of the moulding.

Non-flat parting surface

Parting line which lies on a non-planar or curved surface termed as non-flat parting surface.