Overview of Mold Types and Processes for Injection Molding

During the injection molding process, molds can generally be divided into three categories to meet different production needs and product characteristics.

1. Large sprue mold

The characteristics of the large sprue mold are that the runner and gate are set on the parting line, and the product is demolded together with the mold when the plastic mold making company is opened. This design is relatively simple, with low processing difficulty and low cost, so it is widely used in many production occasions.

2. Fine sprue mold

The runner and gate design of the fine sprue mold is not on the parting line, but directly formed on the surface of the product. Therefore, it requires an additional set of sprue parting lines, resulting in increased complexity in design and processing. The selection of the fine sprue system usually depends on the requirements of the specific product.

3. Hot runner mold

The hot runner mold is similar in structure to the fine sprue mold. The main difference is that its runner is located in the hot runner plate and hot nozzle with constant temperature, which prevents the cold material from demolding. The runner and gate are directly on the product, so demolding is not required. This system is called a sprueless system. Although hot runner molds are difficult to design and process, and the cost is relatively high, they can effectively save raw materials, especially when the raw materials are of high value and the quality requirements of the finished products are strict.

The hot runner system, also known as the hot runner system, is mainly composed of a hot runner sleeve, a hot runner plate, and a temperature control electric box. The hot runner system is divided into two forms: single-point hot runner and multi-point hot runner. The single-point hot runner injects the molten plastic directly into the cavity through the hot runner sleeve, which is suitable for single-cavity single-gate molds; while the multi-point hot runner distributes the molten material to multiple hot runner sleeves through the hot runner plate, which is suitable for single-cavity multi-point feeding or multi-cavity molds.

Injection molding process overview

1. Rubber injection molding: Rubber injection molding injects the rubber directly from the barrel into the vulcanization model, which is a production method with high production efficiency and short molding cycle. Compared with traditional methods, rubber injection molding eliminates the process of blank preparation, reduces labor intensity, and has excellent product quality.

2. Plastic injection molding: Plastic injection molding is a process of injecting molten plastic into a mold under pressure and cooling it to obtain various plastic parts. Currently, polystyrene is the most widely used plastic material, and plastic injection molding machines are mechanical equipment specifically used for this process.

3. Forming injection molding: The finished shape of the molded injection molding is often the final product, and this method does not require further processing. Through injection molding, detailed features such as protrusions, ribs and threads can be formed in one operation.

The above content outlines the different mold types in injection molding and their respective characteristics and applications to help you better understand this key manufacturing process.