Disadvantage is that injection molding machine should have a hydraulic core-pulling function, otherwise core-pulling mechanism cannot be used, shape of mold will increase after oil cylinder is installed.īased on application of above core-pulling mechanism and structural characteristics of plastic parts, core-pulling mechanism with oblique guide posts and side sliders is more suitable. (5) Oil cylinder is combined with side slider core pulling mechanism.Īdvantage of core pulling mechanism is that it can obtain a larger demolding force and a longer core pulling distance, stable transmission, parting and core pulling are not restricted by mold opening time and ejection time. Disadvantage is that processing accuracy is high. The former has a more compact structure, higher requirements for design and processing accuracy.Īdvantage is that T-shaped block can pull core and close mold, can also compress side slider tilt angle is large, so core pulling distance is greater than inclined guide post core pulling distance demolding force is larger. Working principle of T-shaped block lateral core pulling mechanism is basically same as that of inclined guide column slider core pulling mechanism, but structure is different. (4) T-shaped block lateral core pulling mechanism. Core pulling structure is relatively simple, but there is no side slider core pulling safety. It is often used for outer core pulling, and sometimes it is also used for inner core pulling.Ĭharacteristic is to use pushing force of ejection mechanism or mold opening force of equipment (pull hook pull) to drive inclined slider according to its set inclination and ejection distance to complete vertical parting and side core pulling. Inclined slider core pulling mechanism is usually used in occasions where core pulling distance is small, undercut area is large, and a large core pulling force is required. (3) Inclined slider (Huff block) core pulling mechanism. Therefore, outer sliding block can be used without inclined top, inclined top can be used without inner sliding block. Disadvantages are small core pulling force, core pulling area and core pulling distance high precision requirements, complicated processing, easy wear during use, high maintenance rate and troublesome maintenance. Advantage is that inclined top has function of push rod and side pumping, it takes up less mold space. Inclined top core pulling mechanism is mainly used for core pulling of concave and convex parts on inner side of plastic part, and there are also a few applications on outer side. (2) Inclined top (inclined push rod) core pulling mechanism. It is characterized by safety and reliability, low maintenance rate and convenient maintenance. It is the most widely used, accounting for about 60% of all core-pulling mechanisms. Side slider core-pulling is mainly used for outer core-pulling, but there are also a few applications on inner side. In addition to multiple collisions in this part, a lateral core pulling mechanism must be used to demold.įigure 1 Decorative plastic cover for shower head 2 Selection of side core pulling mechanism (1) Side slider core pulling mechanism. Analyzing structure of plastic part, difficulty in molding is that buckle part cannot be forced to demold. At the same time, plastic parts are required to have good injection molding process performance, high production efficiency, and low mold manufacturing costs. Appearance should be smooth, surface should not have injection molding defects such as flash, shrinkage, bubbles, cracks, scratches, etc. Surface of parts is required to be chrome-plated, material of plastic parts should be ABS. 1 Structural analysis of plastic partsįigure 1 shows plastic shower decoration cover plastic parts of sanitary ware, mass-produced.
Mold has a compact structure, reliable action, smooth ejection of plastic part, molded plastic part fully meets design and use requirements, which has certain reference value for design of injection molds of similar plastic parts. Material, structure and molding process of decorative cover are analyzed, lateral core pulling mechanism and injection mold structure are designed.
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