Using a two-color injection molding machine or a two-color mold, it is possible to form plastic parts of two different colors, with different hardness or different materials, in a single process without the need for secondary assembly. It can achieve effects such as the combination of soft and hard materials, two-color buttons, and two-color casings. It is widely applied in scenarios such as home appliance buttons, car taillights, toothbrush handles, and electronic product casings, enhancing the appearance texture and structural integration of the products.