Relationship Between Injection Mold Structure and Product Quality

Update:06-05-2019
Summary:

Injection molding is the key factor that determines the […]

Injection molding is the key factor that determines the quality of plastic products. Why this?

First of all, the injection mould is molded in the process of injection molding plastic products are molded in the mold, although there is a lot of relationship with material fluidity and temperature, but the final injection mold size is the size of plastic products.

Injection mould has three main systems: gating system, molding parts and structural parts.

Gate: The last level where melt enters the cavity from the runner is the gate. The gate can be seen as the last soldier to control the molding. Its cross-sectional area is much smaller than the runner. The gate has a great influence on the product molding. It plays an important role in the injection molding process by adjusting the gate distribution, shape, quantity and size.

A, Gate can control the flow rate of the melt; B, Gate can prevent the melt flow back in the cavity; C, Gate for the melt through the shearing effect, play a role in raising the material temperature, improve the fluidity; D, Gate molding makes the product and runner connection area reduced, facilitate the separation of products and runners.

Cavity: the final volume space of the product, that is, the molding space of the whole product. The forming parts that make up the shape of the product are called concave dies (or negative dies), and the forming parts inside the product are called punches (positive dies). The development of cavity should be decided by budget according to the shape, performance, material and dimension tolerance of the product. The pressure, corrosion, surface effect and demoulding of the product should be considered comprehensively in the process of injection molding. We can neither save nor cut corners.

Injection mold gating system

The pouring system refers to the whole flow part of the plastic before the cavity is injected from the nozzle. It mainly includes the following parts:

Main channel: connect the nozzles until they are connected to the bypass of the mold. This passage is called the main channel. The diameter of the runner is usually within the range of 4-8 mm. It is determined mainly by the design of the product, the properties of the raw materials and the injection molding process. In order to facilitate demoulding, the main runner is often used. With an inward extended structure, the expansion angle is mostly 3-5 degrees.

Divergent channel: After separating from the main channel, it connects the small channel of each type of groove at different position, and the diffluent channel is generally symmetrical and equidistant distribution. The diversion channel is responsible for delivering the melt to each predetermined gate, balancing the pressure, flow and melting state of each person, and even without any negative impact during demoulding. Therefore, the diversion channel is often designed on the half of the dynamic die, mostly in a semicircular shape, and the diversion channel has to be polished to reduce flow resistance and reduce in. Energy loss in flow process;

Cold material well: also known as cold material hole, set at the end of the main channel, used to capture the nozzle between the two injections produced by the temperature of the cold material is not up to standard, to prevent cold material cavity produced adverse effects or plugging gate. The diameter of the cold material well should be between 8-10 mm and the depth should be about 6 mm. In order to facilitate demoulding, it is usually designed to be curved hook or with subsidence groove. The demoulding rod is responsible for pulling it out to assist demoulding.

The structural design of the injection mold is not only considering the size of the product, but also knowing that the injection mold can help optimize the plastic products in the process of injection molding, considering the structural design of the injection mold for the purpose of not producing defective products. A set of molds with reasonable structural design can greatly save the production of injection workers. This, and finished products of injection molding materials. 

As a professional injection mold manufacturer - TAIZHOU HUANGYAN JTP MOULD CO.,LTD., our plastic injection mould design structure more than ten years of practical experience in strict accordance with the quality management system to operate, in the integration of injection mold DFM report will be discussed at a meeting. So as to give a relatively perfect injection mold structure design.