Method for forming articles by injection molding

In a method for forming articles by injection molding in which a melted plastic material is injected into a cavity defined in a mold, said mold including a movable die, a stationary die, and a stamper for imparting a desired pattern to said article, said stationary die having an auxiliary die in contact with and capable of moving along an outer periphery of said stationary die, said method comprising the steps of:

• closing said movable die onto said stationary die under the condition of substantially no pressure, such that a first portion of said auxiliary die is in contact with said movable die and a gap exists between said movable die and a second portion of said auxiliary die;
• injecting said melted plastic material into said cavity, and thereby slightly releasing away said movable die from said stationary die by the pressure of the injected melted plastic material while moving said auxiliary die along said outer periphery to maintain said first portion of said auxiliary die in contact with said stationary die when said melted plastic material is injected;
• and
• pressing said movable die against said stationary die during injection or after injection to press mold said melted plastic material in said cavity while exhausting gas from said cavity through said gap.