Rotational molding design

When designing your product keep in mind how the mold will open and close around the product. The least expensive, least maintenance mold has two pieces. If your product will require multiple piece molds, you are increasing the chance of wear and flashing due to the operator handling and additional parting lines required. The toy industry has mastered the concept of 2-piece mold/product design, resulting in low cost tools used in high production. Two types of parting lines are predominantly used in cast molds; tongue and groove and flat with dowel pin register. Tongue and groove maintains better registration over the life of the mold. Flat and dowel may require maintenance as dowels loosen. A rule of thumb for dowel spacing on the parting line is every 6-7 inches. One of the biggest maintenance problems that molders experience is partline deterioration and flashing, the following steps will help in reducing this problem. Avoid parting line on sharp corners or along knife edges, always add a radius. Avoid vertical parting lines. Multiple piece molds should be designed whenever possible to use slide system or hinge system to guide opening and closing of multiple piece molds, this results in less damage to part line and ease of operator performance.

Rotational Molding Design PDF.