3 Principles and 6 Precautions for Two color Mold Design
First principle: determine the viscosity of the combination of hard glue and soft glue. In addition, note that the melting point of hard glue should be higher than that of soft glue. Do not melt the hard glue when molding soft glue.
1. First shot: hard glue: PA66+second shot: soft glue: TPE is OK
2. First shot: hard glue: PC/ABS+second shot: soft glue: combination of PC is OK
3. The first shot: hard glue: PP+the second shot: soft glue: TPU, because PP material and TPU material are incompatible.
Second principle: make sure that the second shot of soft glue and the first shot of hard glue cannot fall off after forming.
1. The first shot of hard glue is the second shot of soft glue. Try to use a plane to seal the glue.
2. If the side or inclined top is sealed with glue, try to steal 0.1~0.15MM glue at the hard glue sealing position, and use the die steel position to seal the glue.
Third principle: design based on the existing two-color machine of the company.
1. The normal type of the two-color machine is, and the double barrel is side by side.
2. Abnormal two-color machine. Two gun barrels produce a 90 degree style, which is usually customized or secondary modified.
3. If the insert is put into injection molding, the vertical injection molding machine is normally used.
First note:
Shrinkage of hard glue and soft glue shall be scaled according to the shrinkage of hard glue.
Second note:
It takes four minutes for the mold guide post and the relevant positioning mechanism, and the distance should be uniform, because the male mold side is exactly the same during mold design, and it needs to be rotated 180 degrees during molding.
Third note:
The first injection molding hard glue feeding point must use the three plate mold point for glue feeding, or use the hot runner, because the male mold side is exactly the same, and the product needs to be ejected.
Fourth note:
1. The water path at the male mold side should be designed at the inner side of the mold as much as possible, because the male mold side needs to rotate 180 degrees. If the water path is at the outer side, the water path is loose during the rotation of the mold, causing easy water leakage.
2. If the male formwork is connected, the waterway is designed on the open side, and the waterway is fixed on the circle of the injection molding machine.
Fifth note:
When the first injection of hard glue is completed, and the second injection of soft glue is required, when the soft glue needs to be sealed with the hard glue together with the steel position of the mold at the soft glue side, the steel position of the mold needs to make an interference of 0.1~0.2MM. After T0 mold test, if the hard glue is found to be damaged by pressure, fine adjustment can be made.
Sixth note:
1. Complete 3D for full inspection.
2. Rotate the rear die 180 degrees, and then conduct a full inspection to see if there is interference.
3. Create the water pipe of the rear mold at the same part, and then rotate it 180 degrees back and forth for inspection.