Two-color(2k)or over-molding injection molding is an injection molding method that uses two injection systems to inject different kinds of plastic or the same kind of plastic but different colors into the mold cavity simultaneously or successively.

The injection mold that completes bi-color injection molding is called bi-color(2k or overmolding) injection mold or bi-material injection mold.

When designing a two-color injection mold, two sets of molds components must be designed at the same time. The two fixed mold cavities of the one mold are usually different, while the two moving mold cores are the same.

During injection molding production, two sets of molds cores are injection molded at the same time. In each injection molding cycle, a mono-color semi-finished product and a bi-color finished product will be produced.

The two-color injection mold must adopt a special injection molding machine. During plastic injection molding production, the first injection (the first color) and the second injection (the second color) cycle injection actions are respectively completed by exchanging mold cavities.

Two-color injection molding  mainly meet the special needs of product structure or appearance. There are two types of molding: two-color and two-material:

Topworks Plastics 2-color molded products :

  • High precision and stable quality;
  • Good structural strength and durability;
  • Close fit clearance and beautiful appearance;
  • Costs reduction and the products value added.

Application field :

(1) Requirements for product functions such as power switch, mobile phone key, keyboard indicator light, car switch, etc.

(2) Improving Hand Feeling. Some hand-held products require the rubber in the hand-held parts, which will make the hand feel more comfortable. For example, interphone housing, power tool handle, wrench, screwdriver handle, toothbrush handle, thermos cup, etc.

(3) Adding beauty, as an ornament, such as the logo of some parts, if two-color injection molding is adopted, it is beautiful and there is no worry that it will be worn away later.

(4) The local area of the product needs to be electroplated. If the local area or single side of the product needs to be electroplated, the electroplated area is injected into other materials, such as PC.