UPVC Collapsible Pipe Injection Mould: Overview and Design Considerations A UPVC (unplasticized polyvinyl chloride) collapsible pipe injection mould is a specialized tool used in the plastic injection moulding process to manufacture flexible, collapsible pipes with high durability and chemical resistance. These pipes are widely used in applications requiring lightweight, corrosion-resistant, and easy-to-install fluid transport solutions, such as drainage systems, irrigation, and industrial piping. The mould must be precisely engineered to produce pipes with consistent wall thickness, smooth inner surfaces, and reliable collapsibility. Key Features of the Mould 1. Material Selection The mould is typically made from high-grade tool steel or hardened alloys to withstand high injection pressures (typically 500–1500 bar) and prolonged production cycles. Critical components like the core and cavity are often coated with wear-resistant materials (e.g., chromium or nickel) to extend service life. 2. Collapsible Core Mechanism Unlike rigid pipe moulds, a collapsible pipe mould incorporates a retractable core system. After injection and cooling, the core collapses inward or disassembles to allow easy ejection of the flexible pipe without deformation. This mechanism ensures dimensional accuracy while maintaining the pipe’s foldable properties. 3. Cooling System Design Efficient cooling channels are integrated into the mould to ensure uniform heat dissipation, reducing cycle times and preventing warping. UPVC requires precise temperature control (180–220°C) to avoid degradation and ensure optimal flow during injection. 4. Ejection System A combination of ejector pins and air-assisted ejection may be used to remove the delicate pipe without damage. The ejection force must be carefully calibrated to avoid marks or stretching. 5. Surface Finish The cavity and core surfaces are polished to a high gloss (typically SPI-A1 or better) to produce smooth pipe interiors, minimizing friction and preventing material buildup. Manufacturing Process Considerations - Injection Parameters: UPVC’s low melt viscosity requires high injection speeds and pressures to fill thin-walled sections uniformly. - Venting: Proper venting is critical to prevent gas traps, which can cause burns or weak spots in the pipe. - Maintenance: Regular cleaning and lubrication of moving parts (e.g., sliders, collapsible cores) are essential to prevent wear and ensure consistent product quality. Applications and Advantages UPVC collapsible pipes are favored for their lightweight, chemical resistance, and ease of storage/transport. The mould’s design directly impacts production efficiency, with advanced features like quick-change inserts allowing for multi-size pipe manufacturing in a single mould. In summary, a well-designed UPVC collapsible pipe injection mould combines robust construction, precision mechanisms, and thermal management to produce high-performance pipes efficiently. Its complexity lies in balancing collapsibility with structural integrity, making it a critical tool for modern piping solutions.