Injection molding of a part having a nonuniform thickness is provided. One disclosed embodiment of an injection molding device includes one or more side walls, a first mold surface intersecting the side walls and being stationary with respect to the side walls, and a second mold surface intersecting the side walls so as to define with the side walls and the first mold surface a cavity configured to receive a metered amount of injected molten thermoplastic material. The second mold surface is moveable toward the first mold surface in such a manner that a first end of the second mold surface moves a larger physical travel distance toward the first mold surface than does a second end of the second mold surface during a molding process.