An intake manifold assembly (100) includes an inner shell (12) that is inserted into an outer shell (14), and a cover (25) that seals the open end (38) of the outer shell (14). The inner shell (12) includes dividers (16) that form air passages (18). A laser device (40) is traversed along the outer surface of the outer shell (14) along a path (44) corresponds with the inner shell (12) to form a laser weld joint (45). The intake manifold assembly (10) of this invention includes features and methods of assembly that improve the laser weld joints utilized to assemble the plastic intake manifold assembly (10). Both design details and clamping detail are described, every known configuration of U type manifolds can be made by this technique. The technique provides high value and low cost. High reliability is a well known feature of laser welding.