Precautions in plastic mold design

1. Key points in the design of the inlet flow path

The feed inlet should be set in the thicker part of the product to ensure smooth and complete mold filling. It should be set as far as possible in a place that does not affect the appearance and function of the product. The pull rod can be set at the edge or bottom, in the cold cavity near the gate. , In order to facilitate the demolding of runners, large or flat products, it is recommended to use multi-point feeding to prevent product warpage and deformation and lack of material. The position should be selected at the shortest part of the plastic filling process to reduce pressure loss, facilitate mold exhaust, and avoid opening the gate near the elongated core, so as to prevent the material flow from directly impacting the core, causing deformation, dislocation or bending.

The size of the gate is determined by the size, geometry, structure and plastic type of the product. It can be modified according to the mold test conditions. Through mold flow analysis or experience, it can be judged whether the product seam caused by the gate position affects the appearance and function of the product , Can be solved by increasing the cold material cavity. When a mold has multiple cavities, the same product adopts the symmetrical casting method.

2. Precautions for mold design

1. When developing products or trial-manufacturing new products, some users often only pay attention to the initial research and development of the product, and ignore the communication with the mold manufacturing unit. After the product design plan is initially determined, it can ensure that the designed product has a good molding process. It will not modify the finalized design because of the difficulty of processing parts, so that the mold making personnel will make design preparations in advance to prevent inadvertent consideration in a hurry, which will affect the construction period.

2. According to the different requirements of physical and chemical properties, parts materials, dimensional accuracy, mechanical strength, surface finish, service life and economy, choose different types of molds for forming. There are strict requirements on mold materials and molding processes, high-precision molds It needs to be processed by high-precision CNC machine tools. Some parts have special requirements during the forming process. The mold should adopt advanced technologies such as gas-assisted molding, hot runners, and nitrogen bottles.

3. Generally, large-scale stamping dies should consider whether the machine tool has a blank holding mechanism, a multi-station progressive die, etc. When choosing a partner manufacturer, you must understand its processing capabilities. You should not only look at the hardware equipment, but also combine the management level, processing experience and Technical strength, for the same set of molds, the quotations of different manufacturers are sometimes very different, and users must start from their own needs and comprehensively evaluate them.

4. With qualified molds, it may not be possible to produce qualified products in batches. This is mainly related to the selection of machine tools, the forming process and the technical quality of the operators. A good mold must also have a good forming process, preferably Through one-stop cooperation, and try to avoid multi-head cooperation.