Method and system for making plastic cellular parts and thermoplastic composite articles utilizing same

A method of making a thermoplastic composite article, the method comprising:

• providing a mold having a mold cavity with an interior surface to define the shape of the cellular part and at least one resin flow path extending from an outer surface of the mold to the mold cavity;
• providing first and second sets of projections, the first set of projections extending into the mold cavity from a first direction and the second set of projections extending into the mold cavity from a second direction opposite the first direction, the projections defining cells which open to opposing outer surfaces of the cellular part wherein the projections have different lengths, and wherein different portions of the cellular part have corresponding different thicknesses or at least one portion of the cellular part is curved;
• filling the mold cavity, with the projections extending into the mold cavity, with molten plastic resin from the at least one resin flow path;
• removing the cellular part from the mold cavity of the mold after the cellular part hardens;
• heating first and second skin layers of a reinforced thermoplastic material to a softening temperature in the range of 120° C. to 200° C.;
• and
• cold-pressing, at a pressure in a range of 10 bars to 30 bars, in a single step of molding, a stack comprising the heated first and second skin layers and the cellular part between the first and second skin layers to form the thermoplastic composite article wherein the article has substantially corresponding configuration to the cellular part and has either a relatively non-uniform thickness or at least one portion of the article is curved.