In most cases, to remove the moulding from the mould it is necessary to incline the side walls in the direction of removal of the matrix, patrix, and the possible forming segments. Thanks to this inclination, even after a slight shift of the moulded part in relation to the forming element, play appears between them and eliminates the risk of seizure, distortion or damage to the moulded part.
The pictures below show two ways to produce a mould. The left side is made correctly, with perfectly visible inclinations, and the right side is without inclinations, which often makes it practically impossible to remove the moulded part from it.
Picture on the left - the moulded part is quickly and easily removed from the mould.
Picture on the right - without inclination, the moulded part gets stuck in the mould, making it impossible to remove it from the mould, destroying the surface of the moulded part, and highly increasing the risk of its deformation.
The amount of inclination depends on the smoothness of the moulding surface. For light matt surfaces (Ra = 0.8 μm), the smallest angle of inclination of the side wall is 2°. For medium rough surface (Ra = 1.25 μm) the inclination is 3°30'. For heavily matt surfaces (Ra = 2.5 μm), the inclination must not be less than 5°.
We recommend using as much inclination as possible in order to avoid potential problems with the removal of moulded parts and surface quality..