Basic Structure Of Injection Mold
Different plastic products may have different mold structures due to different plastic varieties, product shapes and structures, and types of injection molding machines, but their basic structures are the same.
The injection mold consists of two parts: the movable mold and the fixed mold:
The movable mold is that the injection mold will be opened before the product is ejected or removed after the production of the injection mold is completed. When the injection mold is opened, the moving part is the movable mold, and the immobile part is the fixed mold.
During the product production process, the material is injected into the plastic particles from the nozzle of the injection molding machine from right to left, and then cooled and formed.
Since the joint part between the injection molding machine nozzle and the mold is generally immobile, the part of the mold that the injection molding machine nozzle contacts is the fixed mold. It is closest to the nozzle of the injection molding machine, so the mold is fixed on the vertical injection molding machine (injection from top to bottom), also called the upper mold, and the mold is fixed on the horizontal injection molding machine (injection from left (right) to right (left)) Also called front mold. Correspondingly, the movable mold is also called the lower mold and the rear mold.
Since the mold core of the fixed mold that forms the cavity is generally concave, the fixed mold is also called a concave mold or a female mold. The mold core of the movable mold is correspondingly convex and is also called a male mold or a male mold.
Mold Composition
The upper mold fixing plate is fixed on the injection molding frame (nozzle side of the injection molding machine). The front template and front mold core are fixed on the upper mold fixed plate.
Templates and molds. The main function of the template is to carry the mold core. There are cooling channels inside to cool the product located in the cavity after the injection is completed. The front and rear mold cores form the cavity, which is the empty area that the plastic flows into and fills.
Guide sleeves and guide posts. The guide bush is equivalent to a sliding bearing, and the guide pillar slides in it when opening and closing the mold. The guide pillar is mainly used for positioning during the mold opening and closing process to prevent the upper and lower templates from being misaligned after mold closing. It belongs to the mold rough positioning system.
The mold feet support the space for the ejection system. The space supported by the mold foot contains upper and lower ejector plates, ejector pins, return pins, etc.
The upper and lower ejector plates are used to fix the ejector pins (lock the lower end of the ejector pins). The ejector plates move in the direction of ejecting the product during the product demoulding process. The power source is generally a hydraulic cylinder; the ejector pins follow the ejector plate during the product demoulding process. The movement pushes the product out to achieve demolding; the return pin is pressed against the front template during the mold closing process to return the ejector plate. If there is no return pin, a spring can be used to return it.
A, B, C boards. The mold part before the front mold fixing plate and the rear mold fixing plate generally has a three-stage structure, that is, A, B, and C plates. A plate is composed of the front mold core + front template, and B is composed of the rear mold core + rear template. board, and the remaining section is board C.
In order to reduce the heavy mold design and manufacturing workload and save costs, simple products generally use standard mold bases, and only process mold cores and some details for different products.
Product structure design mainly involves understanding the basic structure of the mold. After all, it is not the mold industry, so you only need to have a general understanding. The six major systems of the mold: glue feeding system, molding system, exhaust system, temperature adjustment system, ejection system, and mold base system.
