In a method of uniforming the thickness of a rib, steps are forming a plurality of blocked layers by many times of printing and stack, processing a first pre-bake of each blocked layer printed, processing a second pre-bake of in the final blocked layer, flattening the final blocked layer by the uniform plate, and solidify the blocked layers by a sintering process in the final to form a rip (insulation structure), thereby the thickness of rip being uniform.