Description
Connectors are a plastic product that electronic engineering technicians often come into contact with. Its function is very simple: to build an electrified bridge between blocked or isolated circuits in the circuit, thereby allowing current to flow and the circuit to achieve its intended function. Connectors are widely used in computers, data communications, consumer electronics, automotive appliances and industrial appliances.
Mold design process
1. Cavity layout
The cavity layout of the plastic part on the mold: including the number of cavities and their arrangement on the mold. Generally, the number of cavities needs to match the tonnage of the injection molding machine selected. At the same time, production efficiency and economic benefits must be considered. More importantly, the structure of the plastic part and the complexity of the mold structure must also be considered. Since this plastic part is relatively small, multiple cavities are usually arranged. However, both sides of this plastic part are molded by sliders and have a large number of PIN holes. Therefore, this plastic part adopts a 1-mold 2-cavity layout, that is, two plastic parts are injection molded at one time. pieces.
2. Design of parting surface
The parting surface design must first analyze the parting of the plastic part: ① It must be conducive to ensuring the accuracy of the plastic part; ② It must be conducive to the processing and manufacturing of the mold, especially the processing of the cavity and core, and it must be dismantled into a grinder as much as possible; ③ It must be It is conducive to the design of the exhaust system; ④ It should be conducive to the demoulding of plastic parts and ensure that the plastic parts remain on the side of the movable mold after the mold is opened.
3. Design of pouring method
The plastic enters the parting surface from the main channel, and then enters the mold cavity along the runner. The gate is located at the head of the plastic part to prevent flow marks. A pouring point overflow should also be made at the head on the other side. The pouring point adopts latent glue feeding, which can be automatically cut off during the ejection process. This saves one step in post-processing and saves costs.
4. Design of core pulling mechanism
The side walls of this plastic part are all undercut, and the core and cavity cannot be formed. Therefore, slider molding is required. Because the side walls on both sides are formed on the slider, the trapped air will cause bubbles or scorch in the plastic part. For such phenomena, the slider needs to be divided into several pieces and vented. Since many shapes of plastic parts are formed in the mold cavity, in order to prevent the plastic parts from sticking to the fixed mold cavity, the slider needs to add a delayed exit mechanism.
5. Ejection mechanism design
Since most of the molding of plastic parts is in the mold cavity, after the slider exits, the core has almost no adhesion force. It is enough to arrange a row of ejector pins in the middle of the core to assist in ejection. Because of the latent glue feeding, and the glue feeding point In the mold setting, the runner needs to use a pull rod to pull out the material head.
6. Cooling system
In order to ensure the stability of the injection molding cycle, cooling water channels are designed on both the movable mold side and the fixed mold side. Since the plastic parts are relatively small, the water channels are also designed to be relatively simple, as shown in Figure 7.
7. Exhaust system
A good exhaust system design is of great help to the injection mold. Because the connector mold requires precise processing and the shape is complex, it is generally disassembled as much as possible. It is disassembled into a grinder for processing to ensure machining accuracy; the exhaust is added to prevent trapped air. Therefore, in the disassembled cavity and core, exhaust slots need to be opened in places that do not interfere with the ejector pin.