Mold and process for making a very thin wall article

A process for optimizing a molding temperature during flow of molten molding material into a mold cavity, the molding material to flow while molten in the mold cavity from at least one point of injection, along a flow path having a width defined by cavity walls, and the molten material transferring heat energy to the mold cavity for cooling and setting the molten material in a shape determined by the mold cavity, said transferring of heat energy being determined by temperatures and thermal properties of the molten material and the mold cavity, the process comprising the steps of:

• providing a mold cavity controllable to a predetermined pre-injection temperature that is lower than a temperature at which the molding material sets, wherein the mold cavity can be heated temporarily by injection of the molten molding material at an injection temperature that is higher then said temperature at which the molding material sets and said material thereafter cools by transfer of heat energy into the cavity, to a post-injection temperature cool enough to harden the molding material;
• determining a material flow path in the mold cavity between a point of injection of the molten molding material and a remote part of the mold cavity to be filled with the molten material by flow from the point of injection;
• predetermining the pre-injection temperature of the cavity and the injection temperature of the molten material, and mathematically determining a thickness of a thermal insulation temperature booster at least along a part of the mold cavity along the flow path, such that a temperature of the molding material is elevated to an extent that the molding material remains at a temperature higher than the temperature at which the molding material sets, until the molding material has filled the mold cavity to form a molded article;
• cycling the molding cavity while applying a substantially constant temperature control stimulus to the mold cavity, said cycling comprising successively and repeatedly bringing the mold cavity to a predetermined pre-injection temperature below a setting temperature of the molding material;
• injecting the molten molding material so as to elevate a temperature of the mold cavity at the temperature boosters to a temperature at least 10 degrees C. above setting temperature of the molding material;
• and completely filling the mold before a flowpath in the cavity is occluded by progress of setting of the molding material in the cavity.