A plastic molding is a tool for producing plastic products. It consists of several sets of parts with a molded cavity. During injection molding, mold is clamped on the injection molding machine, molten plastic is injected into molding cavity, and is cooled and shaped in the cavity, then the upper and lower molds are separated, product is ejected from the cavity through ejection system to leave mold, and finally mold is closed. For the next injection, the entire injection moulding process is cyclic.
1). Mold composition
Although structure of mold may vary depending on the type and performance of plastic (moulding material), shape and structure of plastic product, and type of injection machine, the basic structure is uniform. The mold is mainly composed of a gating system, a temperature control system, a molded part and a structural part. The gating system and molded part are in direct contact and vary with plastic and product. It is the most complicated and most varied part of mold, and requires the highest degree of smoothness and precision.
1-1). Gating system
The gating system refers to the part of flow path before plastic enters the cavity from nozzle, including main channel, cold material hole, shunt channel and gate. The gating system, also known as runner system, is a set of feed channels that direct plastic melt from injector nozzle to cavity, typically consisting of a main flow path, a split runner, a gate, and a cold feed pocket. It is directly related to molding quality and production efficiency of plastic products.
1-2). Temperature control system
In order to meet mold temperature requirements of injection moulding process, a temperature adjustment system is required to adjust temperature of mold. For plastic molding, cooling system is primarily designed to cool mold. The common method of mold cooling is to open a cooling water channel in the mold, and use circulating cooling water to take away the heat of mold. In addition to using hot water or steam of cooling water channel, heating of mold can also install electricity heating element inside and around the mold. .
1-3). Molded part
Molded parts refer to various parts that make up shape of product, including moving molds, fixed molds and cavities, cores, forming rods, and exhaust ports. Molded part consists of a core and a die. The core forms inner surface of article and die forms outer surface shape of article. After clamping, core and cavity form cavity of mold. According to process and manufacturing requirements, sometimes core and die are made up of several pieces, sometimes be made into a whole, and only the inserts are used in the parts that are easily damaged and difficult to process.
1-4). Structural part
It refers to various parts that make up mold structure, including: guiding, demoulding, core pulling and various parts of parting such as front and rear splint, front and rear buckle template, bearing plate, pressure column, guide column, stripping plate, stripping rod and return rod.
2). Injection device
Injection device is a device that causes resin material (moulding materials) to be melted by heat and then injected into mold. The resin is extruded from head into barrel, and the melt is conveyed to the front end of barrel by rotation of screw. In that process, resin material (moulding materials) in the barrel is heated by action of heater and melted under shear stress of screw. The molten resin of the main channel and the runner, corresponding to the molded product is retained at the front end of the barrel (referred to as metering), the screw continuously feeds material into mold cavity. When the molten resin flows in the mold, moving speed (ejection speed) of screw must be controlled, and pressure (pressure maintaining) is controlled after resin is filled in the cavity. When screw position and injection pressure reach a certain value, we can switch speed control to pressure control.
Haifu Mould, China plastic molding manufacturing with 20 years of experience in mold production, was established in 1998. We specialize in the development of plastic mold, die casting mold, parts production and product assembly. We have modern production facilities, covering an area of 4,000 square meters, construction area of 6,000 square meters, and more than 120 employees. Haifu Mould has Taiwan high-speed CNC, Taiwan inspection machine and more than 30 large-scale CNC equipment. Our molds are mainly exported to the United States, Europe, the Middle East and other countries. Our customers including DURA Automotive Systems, Brose Fahrzeugteile GmbH & Co, Precise Global Pty Ltd, Purafil Inc, ANVA Polytech, Aditya Auto products & Engineering (I) Pvt. Changfei, Hafei, Lifan, Ford in China and so on. We sincerely welcome you to visit our company and expand your business!
