In production of modern plastic products, lateral core pulling technology is an integral part of injection mold design. It allows molds to produce plastic parts with complex geometries, which are increasingly common in daily life and industrial applications. This article will explore differences in application of lateral core pulling technology on different plastic materials, analyze challenges it faces in mold design, and introduce working principle of lateral core pulling mechanism in detail.

Adhesion and shrinkage of plastic materials are key factors affecting core pulling force and core pulling distance. For example, materials such as polypropylene (PP) and polyethylene (PE) may adhere more tightly to mold during cooling, so a larger core pulling force is required to demold. Designers must calculate required core pulling force based on characteristics of material to ensure that mold can effectively remove molded plastic part from mold.

Different plastic materials have different degrees of wear on mold, which requires mold materials and surface treatment technology to adapt to different plastic properties. For example, materials such as polytetrafluoroethylene (PTFE) and polyimide (PI) may cause greater wear on mold during molding process, so more wear-resistant mold materials or special surface treatments such as coating or hardening may be required.

Mold temperature has a direct impact on fluidity and molding quality of plastics. For example, for heat-sensitive plastics such as polycarbonate (PC), too high mold temperature may cause material degradation, while too low temperature may cause poor molding. Therefore, designers need to accurately control mold temperature according to thermal properties of plastic material.

 

Selection of lateral core pulling mechanism depends on characteristics of plastic material and geometry of product. For plastics with higher hardness or higher melting point, more powerful core pulling mechanisms such as hydraulic or pneumatic lateral core pulling mechanisms may be required. These mechanisms can provide greater core pulling force and longer core pulling distance to accommodate complex product designs.

Fluidity of plastic affects mold design, especially design of lateral core pulling mechanism. Plastics with good fluidity are more likely to fill mold cavity, but may also require a more sophisticated core pulling mechanism to prevent material from deforming during core pulling process.

Plastics have different shrinkage rates, which will affect core pulling distance and core pulling time in mold design. Plastics with high shrinkage rates may require longer core pulling distances and more precise core pulling control to ensure dimensional accuracy of product.

Thermal expansion coefficient of plastics affects dimensional changes of mold during heating and cooling, which affects design and operation of lateral core pulling mechanism. Designers must take these changes into account to ensure stability and reliability of mold at different temperatures.

Some plastics may corrode mold material, which requires selection of corrosion-resistant mold materials or special surface treatment. For example, polyvinyl chloride (PVC) may release corrosive gases at high temperatures, so special mold materials and protective measures are required.

Lateral core pull mechanism is a key component used in injection molds to form lateral features of plastic parts. Its working principle usually involves following steps:

The two or more parts of mold are closed to form main shape of plastic part. Then, molten plastic is injected into mold cavity to fill main part of part.

When plastic begins to solidify but has not yet fully hardened, lateral core pull mechanism begins to act. This usually involves driving elements such as inclined guide pins, bending pins, hydraulic or pneumatic elements, which push lateral core or slider to move to form lateral features of plastic part.

Plastic cools and solidifies in mold. During this process, lateral core pull mechanism maintains its position to ensure that lateral features of plastic part are properly molded.

Mold is opened and lateral core pull mechanism is reset to remove already molded plastic part. This step usually involves reverse movement of lateral core or slide to ensure that they do not hinder demolding of plastic part.

Plastic part is removed from mold and is ready for subsequent processing or packaging. This step requires ensuring that plastic part has been fully cured and that lateral features are not damaged by demolding.

Lateral core pulling technology is a key technology in injection mold design, which makes it possible to manufacture plastic parts with complex geometries. Designers must consider characteristics of different plastic materials and their impact on mold design and operation. Quality and accuracy of plastic parts can be ensured by accurately calculating core pulling force and core pulling distance, selecting appropriate mold material and surface treatment technology, and controlling mold temperature. In addition, understanding working principle of lateral core pulling mechanism is essential for designing efficient and reliable molds. With continuous advancement of plastic materials and mold technology, lateral core pulling technology will continue to play an important role in manufacture of plastic products.