For plastics that have good fluidity and are prone to overflow during injection mold processing, the insert fracture method should be selected according to the type to prevent the generation of burrs. For products with high height and small demolding angle, central parting can be used, and the mold cavity can be divided into two ends for easy demolding. In order to easily release the product from the mold, it is necessary to set the release angle on the mold, which depends on the shape of the product.

The plastic processed by injection molding has different mold structures, surface accuracy, and processing methods, usually 1-3 pieces. The larger the demolding angle, the better, without affecting the appearance and performance of the product. The diversion channel is the connecting part of the main channel, located between the main channel and the gate, and has the function of diversion and turning. The diversion channel needs to transport the molten plastic to the gate for mold filling at a faster speed with low pressure loss.

The perimeter of a square processed by an injection mold is longer and the circle is shorter. If the area is too small, it will reduce the plastic flow rate, prolong the filling time, and easily cause product shortage, paste, silver thread, and shrinkage; If it is too large, it is easy to accumulate too much gas, increase cold material, extend production cycle, and reduce production power. Different plastic materials have different diversion channels.

But there is a planning principle for injection mold processing: it is necessary to ensure that the ratio of surface area to volume of branch channels is small, that is, when the length of branch channels remains unchanged, the ratio of surface area or lateral area to cross-sectional area of branch channels is small. There are many types of diversion, which vary with different plastics and mold structures. The common types are circular, semicircular, rectangular, trapezoidal, U-shaped, and regular hexagonal.

The basic principles of injection mold processing planning:

When conditions permit, the cross-sectional area and length of the splitter should be as small as possible.

When the diversion pipe is long, a cold material chamber should be set at the end to accommodate the cold material and prevent air from entering. A pull rod is usually set on the cold material chamber to facilitate the demolding of the rubber channel.

3. In multi cavity molds, the diversion channels should be as consistent as possible and the length should be as short as possible. The cross-sectional area of the main flow channel should be greater than the sum of the cross-sectional areas of the diversion channel.

4. Its surface does not need to be too smooth (Ra=1.6 or so), which is beneficial for insulation.

If there is a large amount of diversion, consideration should be given to adding a diversion cone, which can prevent molten plastic from directly impacting the mold cavity and prevent plastic from turning sharply, making the plastic transition smooth.

6. The runner is generally allocated using the balance method, and in special cases, the imbalance method can be used. All cavities require balanced filling with glue simultaneously, with a compact layout and short process to reduce mold size.

When planning the flow path for injection mold processing, a smaller proportion should be used first, in order to have a correction margin after mold testing.