Method and insert for manufacturing a multi-density shoe sole

A method for manufacturing a shoe sole (3) by injection moulding sole material onto a shoe upper (2) mounted on a last (45), forming a lasted shoe upper, where the sole is attached to the shoe upper after repeated injections, the method comprising:

• placing a shoe sole shaping insert (16) in a mould (31) prior to a first injection, the mould having an injection chamber, movable side frames (32), and a vertically moveable bottom piston (33), the shoe sole shaping insert (16) positioned entirely inside the injection chamber;
• injecting a first sole material of a given colour and given density into a first cavity (36) through a first mould injection channel (34);
• removing the shoe sole shaping insert (16) from the mould after the first injection and prior to a second injection;
• and
• injecting a second sole material of another colour and/or density through a second injection channel (35) into a second cavity made by removal of the shoe sole shaping insert,
• wherein the first cavity occupies a first continuous area along a length of the injection chamber, the second cavity occupies a second continuous area along the length of the injection chamber, and the shoe sole shaping insert separates the first and second cavities along the length of the injection chamber.