2k injection mould design

Check items before design

• ① 2k injection mould material.
• ② The structure of the moulded product.
• ③ The choice of 2k injection moulding machine.
• ④ The basic structure of the formwork.

Determine the cavity and combination of 2k injection mould

Determining the sequence of 2k injection moulding is a very critical step in the design of 2k injection mould, which is related to the success or failure of the entire mould design.

• ① Consider the fluidity of the plastic and choose an appropriate wall thickness. Because the melt of the second injection has to climb over the semi-finished product after the first injection moulding, if the wall thickness of the second injection moulding is not enough, it will cause filling difficulties, which will easily lead to lack of material, shrinkage dents, weld marks, etc. defect. Generally speaking, the wall thickness of the secondary material must be above 0.8mm, preferably 1/20 of the entire wall thickness.
• ② If the moulded plastic part is composed of hard rubber and soft rubber, in most cases, the hard rubber part of the plastic part is injected first, and then the soft rubber part of the plastic part, because the soft rubber is easy to deform.

Gating system design requirements

• ① The injection pressure is low.
• ② Fast filling improves the labor productivity of the mould.
• ③ The injection is uniform and the quality of plastic parts is better.
• ④ Reduce waste and shorten injection time.

Choose injection moulding equipment

• ① According to the injection volume of each injection barrel, decide which barrel to use for which colour.
• ② The position and stroke of the striker.
• ③ Problems with the configuration of the water circuit, oil circuit and circuit on the rotating template.
• ④ The carrying weight of the rotating template.