Mechanical interlock pin assembly

An injection molding system, comprising:

• a first mold plate defining a mold cavity;
• a second mold plate opposing the first mold plate;
• and
• a mechanical interlock pin assembly coupled to the second mold plate, comprising:
• a shaft having a first end and a second end,
• a set of helical spline elements disposed at the first end of the shaft, the set of helical spline elements extending along a longitudinal axis of the shaft, and
• a bearing rotatably coupled to the second end of the shaft, the bearing configured to allow rotation of the shaft between a first rotational position and a second rotational position relative to a mold cavity,
• wherein the set of helical spline elements extend from a shoulder portion disposed at the first end of the shaft,
• wherein an outer diameter of the set of helical spline elements is less than an outer diameter of the shoulder portion, and
• wherein each spline element of the set of helical spline elements is disposed at a pitch of between about 2° and 30° relative to the longitudinal axis of the shaft.

In an injection molding system, a method for forming a two-shot molded element, comprising:

• disposing, by the injection molding system, a distal portion of a shaft of a mechanical interlock pin assembly within a mold cavity between a first mold plate and a second mold plate, the distal portion of the shaft having a set of helical spline elements extending along a longitudinal axis of the shaft, wherein each spline element of the set of helical spline elements is disposed at a pitch of between about 2° and 30° relative to the longitudinal axis of the shaft;
• injecting, by the injection molding system, a first shot material into the mold cavity;
• withdrawing, by the injection molding system, the second mold plate and the shaft of the mechanical interlock pin assembly from the first shot material to define a splined mechanical interlock path therein;
• disposing the first mold plate and first shot material relative to a third mold plate;
• and
• injecting, by the injection molding system, a second shot material into the mold cavity between the first mold plate and the third mold plate;
• wherein withdrawing the shaft of the mechanical interlock pin assembly from the first material to define a splined mechanical interlock path therein comprises translating, by the injection molding system, the mechanical interlock pin assembly along a linear direction opposing the mold cavity to rotate the shaft from a first rotational position to a second rotational position relative to the mold cavity.