I. Product Overview

The 1-to-8 needle valve hot runner system is a high-end injection system designed for high-precision, automated mass production of single-mold, eight-cavity parts. It features a balanced manifold structure paired with eight sets of independent needle valve hot nozzles, using pneumatic mechanical valve needles to precisely control the opening and closing of each gate. The system features balanced and stable flow channels and uniform material delivery, enabling simultaneous filling and molding of all eight cavities. It completely resolves issues such as uneven filling, surface defects, gate residue, and stringing in multi-cavity molds, making it the mainstream standard hot runner solution for high-volume production of small and medium-sized precision plastic parts.

II. System Structure and Principles

Melt enters the main runner bushing through the injection molding machine’s nozzle and is evenly distributed across eight stages via an H-shaped symmetrical balancing manifold before being delivered to eight needle-valve hot runners. The system features a pneumatic drive mechanism, where cylinders precisely open and close the gate needles. During injection, the needles open to allow material flow; after the holding pressure phase ends, the needles close to cut off the flow. This ensures no cold material residue remains in the cavities and no scrap material in the runners, enabling fully automated, gate-less molding production.

The entire system employs a “one nozzle, one temperature control” design with independent temperature measurement and heating, ensuring precise and controllable temperatures for all eight nozzles and high consistency in molding parameters across all cavities, making it suitable for long-term, stable mass production.

III. Core Structural Configuration

1. Balanced Eight-Cavity Manifold

Constructed from H13/P20 hot-work die steel, the manifold is integrally forged and normalized. The runner system features an equal-length, balanced H-shaped layout, precision-machined on a five-axis machine and mirror-polished. Runner resistance is uniform, with no dead corners or material stagnation, ensuring clean and smooth color changes. The plate is pre-embedded with independent heating elements and temperature measurement ports, enabling zone-specific constant-temperature control to ensure high consistency in pressure, flow rate, and temperature across all eight cavities.

2. Eight Sets of Precision Needle Valve Hot Runner Assemblies

Equipped as standard with eight identical high-precision needle valve hot runner assemblies, featuring a stable nozzle body structure and uniform heat conduction. The valve needles are made of SKD61 steel and undergo vacuum quenching and nitriding treatments, resulting in high hardness, wear resistance, and resistance to deformation. Paired with high-precision guide sleeves, they ensure smooth, jamming-free reciprocating motion. Gates are mechanically forced to break off, ensuring molded products are free of gate marks, stringing, and cold runner tails, meeting requirements for high-gloss finishes and precision assembly.

3. Pneumatic Synchronous Drive System

A stable pneumatic drive structure enables synchronized opening and closing of all eight needles or sequenced, time-delayed operation. With rapid response and precise control, this system effectively mitigates issues such as weld lines, shrinkage, and warpage, making it suitable for multi-point injection of large parts and multi-cavity molding of precision small parts.

4. Independent Temperature Control System

The system is fully equipped with eight independent temperature control channels, with one circuit per nozzle, ensuring precise temperature control within ±1°C. It features alarm and protection functions for overheating, wire breakage, and short circuits, effectively preventing plastic carbonization, decomposition, and nozzle clogging, thereby ensuring long-term stability during mass production.

5. Thermal Insulation and Sealing Structure

Each hot runner is equipped as standard with high-temperature copper gaskets, ceramic thermal insulation spacers, and thermal insulation support columns for the manifold. This effectively isolates the mold from low temperatures, reduces heat loss, and prevents material overflow, leakage, and high-temperature carbonization at the joint surfaces, significantly extending the system’s service life.

IV. Core Product Advantages

1. High Consistency Across All Eight Cavities

The symmetrical, balanced runner design ensures even material flow into all eight cavities, resulting in high consistency in product weight, dimensions, and appearance, and significantly reducing the defect rate.

2. Fully Automated Sprue-Free Production

Mechanical sealing completely cuts off the material flow, eliminating drips, stringing, and sprue waste, thereby saving raw material costs and making the system compatible with automated production lines.

3. Significantly Improved Molding Quality

Smooth, mark-free gates eliminate the need for post-processing sanding; sequential material injection effectively mitigates common defects such as weld lines, warpage, and shrinkage.

4. High Production Efficiency and Stable Cycle Times

Eliminating cold runner cooling time shortens molding cycles; simultaneous mass production across all eight cavities significantly boosts production capacity, making it ideal for high-volume, standardized production.

5. Wide Range of Compatible Materials

It reliably supports a variety of materials, including ABS, PP, PC, PMMA, PA, POM, LCP, glass-fiber-reinforced materials, flame-retardant materials, and medical-grade plastics.

V. Applicable Products and Industries

The 1-to-8-cavity needle-valve hot runner system is a highly versatile, standard multi-cavity precision mass-production system widely used in 1-mold-8-cavity mass-production molds for precision electronic components, plastic housings, connector structural parts, small automotive plastic parts, home appliance components, medical consumables, packaging components, and precision parts for daily necessities.

VI. Application Scenarios

Products with high aesthetic requirements; no gate marks or stringing/flash allowed

High-volume mass production requiring stable, high-yield production

Multi-cavity products with significant variations requiring balanced material injection to improve consistency

Molding of engineering plastics, transparent materials, and glass-fiber-reinforced modified materials

Automated, unmanned production with no manual handling of sprue ends required