1. Filling conditions

Before deciding on a lead system, it is first necessary to define the orientation of the part in the mold at the time of filling, in other words its molding direction. This is the design of the part's feeding mode (or feeder) [1][2] , which should normally take precedence over all other considerations. In many cases, however, parameters relating to the equipment, tooling or molding processes used in a given workshop – number and layout of parting lines, for example – or to the presentation of certain parts – machined parts to be placed in the bottom of the cavities.

Our intention is not to develop this aspect of the question, which is beyond the scope of this dossier; we can, however, state a principle that is worth keeping in mind.