Scientific Achievement Registration: Open Hot-Runner Overmolding High-Speed Multi-Cavity Mold

The Zhejiang Provincial Department of Science and Technology, as the highest administrative authority for S&T work in the province, is responsible for organizing and implementing S&T achievement registration. S&T achievement registration is an important part of S&T achievement management, implemented in accordance with the “Measures for S&T Achievement Registration” (Guo Ke Fa Ji Zi [2000] No. 542). All research projects that have passed appraisal, acceptance inspection, or have obtained patents may apply for registration. Registered S&T achievements are uniformly numbered by the Zhejiang Provincial Department of Science and Technology and, after public announcement, are issued an S&T Achievement Registration Certificate. This certificate is a required attachment for applying for the Zhejiang Province S&T Award and is also an important basis for enterprises to qualify for High-Tech Enterprise, Technology-Based Enterprise, High-Tech Enterprise R&D Center, and other qualifications. The registration process requires technical appraisal, novelty search, and expert review to confirm the innovativeness, maturity, and application and promotion value of the technology. Zhejiang SINOMOULD Co., Ltd.’s independently developed “Open Hot Runner Stack Multi-Cavity High-Speed Injection Mold” was registered as an S&T achievement by the Zhejiang Provincial Department of Science and Technology. This technology achieves the integration of hot runner systems and stack molding processes, solving the industry challenges of runner balancing and material waste in multi-cavity injection molding, signifying that SINOMOULD’s key technological breakthrough in the field of precision injection molds has received provincial-level authoritative certification.

Hot Runner Technology Principles: Core Driver of Material Savings and Efficiency Improvement

A hot runner is an advanced gating system using a heating method. Through the functions of the hot runner manifold, hot nozzles, and their control system, the plastic throughout the entire runner from the injection molding machine nozzle to the mold cavity gate is kept in a molten state at all times. After injection is completed and the mold is opened, only the product needs to be removed, without having to remove the solidified waste material in the runner. This technology principle brings significant economic benefits: it can save 30% to 50% of raw materials, reduce injection molding machine energy consumption by 20% to 30%, leave small gate marks, and support fully automated production. For multi-cavity injection molds, the advantages of hot runner systems are particularly prominent — they can significantly shorten molding cycles, improve machine efficiency, and ensure quality consistency across multiple cavity injection molded parts.

In mold design, the core innovation of this technological achievement lies in the collaborative design of the hot runner system and the stack molding process. Hot runner system design involves key aspects such as hot nozzle selection, manifold structure, and temperature control systems. SINOMOULD’s design team optimizes the melt transmission path in the runner plate, combined with mold flow analysis software to conduct simulation verification of hot runner temperature distribution and pressure balance, ensuring melt flow balance during the multi-cavity filling process and avoiding inconsistencies in product weight and quality caused by runner imbalance. The stack mold structure further improves output efficiency per unit time, enabling a single mold to produce more products within the same injection cycle.

Multi-Cavity Runner Balancing: Systematic Solution to an Industry Challenge

In multi-cavity injection molding production, the problem of unbalanced filling among cavities frequently occurs, leading to inconsistent product weight and quality among the cavities. This problem is typically caused by factors such as instability in the molding process, ambient temperature variations, and changes in localized mechanical properties of the machine or mold. SINOMOULD’s R&D team precisely designs the runner layout of the hot runner system, enabling uniform distribution of melt through the manifold to each nozzle. Through reasonable heating element arrangement and temperature control system design, consistent temperature across all runners is ensured, reducing flow imbalance caused by temperature differences. This systematic runner balance control ensures filling consistency across all cavities during the injection molding process.

In injection molding, this technological achievement effectively shortens the molding cycle. The hot runner system keeps the plastic in the runner in a molten state at all times, eliminating the need to remove runner solidified material after each molding cycle, significantly shortening the mold opening and part removal time. The stack mold structure enables a single mold to simultaneously mold products on multiple levels, further improving output efficiency per unit time. Shorter molding cycles not only directly improve production efficiency but also reduce the number of thermal cycles the mold undergoes at the same output level, helping to extend mold service life.

Mold Manufacturing and Quality Control: Precision Machining Ensures Technology Implementation

The manufacturing of hot runner stack multi-cavity molds places extremely high demands on machining precision. The ultra-slender runner hole machining of the hot runner manifold and precision manufacturing of radial hot runner cluster holes require high-precision processing equipment and mature process experience. In mold manufacturing, SINOMOULD relies on high-precision CNC processing equipment and a systematic precision manufacturing process system to ensure the machining precision and surface quality of key components such as hot runner manifolds and hot nozzles, providing manufacturing assurance for the temperature uniformity and flow balance of the hot runner system.

In quality control systems, SINOMOULD has passed ISO9001 Quality Management System certification and IATF 16949 Automotive Industry Quality Management System certification, establishing a full-process quality control system covering mold design review, processing process monitoring, and assembly, commissioning, and inspection. Each hot runner stack multi-cavity mold undergoes strict trial mold verification and dimensional inspection before delivery, ensuring that key indicators such as hot runner system sealing, temperature control precision, and flow balance meet design requirements, providing customers with stable and reliable production assurance.

Customer Value: Triple Assurance of Material Cost Reduction, Cycle Shortening, and Product Consistency

For injection molding production enterprises, material costs, molding cycle, and product quality consistency directly determine production costs and market competitiveness. SINOMOULD’s “Open Hot Runner Stack Multi-Cavity High-Speed Injection Mold” technological achievement, through the integration of hot runner systems and stack molding processes, brings customers the triple value of significantly reduced material costs (saving 30%-50% raw materials), substantially shortened molding cycles, and highly consistent multi-cavity product quality. The technological maturity assurance certified by provincial-level S&T achievement registration provides reliable technical support for customers’ high-volume precision injection molding production.

According to the management requirements of the Zhejiang Provincial Department of Science and Technology, the S&T Achievement Registration Certificate is a required attachment for applying for the Zhejiang Province S&T Award, and registered achievements are incorporated into the provincial S&T achievement database for unified management. SINOMOULD will continue to advance in-depth R&D and industrialization of hot runner stack mold technology, consolidating its technological leadership position in the field of precision injection molds.