The clamp force is the maximum force required to keep the mold closed during filling. This force can be calculated.
The calculated maximum clamp force is a function of injection pressure and the projected area of the part. The projected area is the area of the model that is projected onto the XY plane. For the clamp force calculations to be correct, the model must be positioned so that the clamp force is applied along the Z axis direction as shown in the following diagram.
The part design and orientation can impact on the clamp force required for molding.