Product Overview

A hot runner system is a complete set of temperature-controlled injection molding equipment designed specifically for injection molds. It uses electric heating to continuously maintain the molten state of the plastic within the manifold and hot nozzles, eliminating the traditional cold runner molding process that produces solid sprue material and enabling sprue-less, low-waste, and highly efficient automated injection molding. Based on cavity layout, aesthetic requirements, and material properties, the complete system is categorized into open-type, needle-valve-type, close-pitch multi-cavity, and single-to-multi-cavity standardized series, suitable for the precision mass production of general-purpose plastics, transparent optical materials, high-temperature engineering plastics, and medical-grade materials.

Core Components

Distributor Plate

Forged and machined from H13 and P20 hot-work die steel, the runner system features equal-length, balanced, mirror-polished runners. Layout options include linear, H-shaped, X-shaped, and radial configurations. The manifold is pre-equipped with embedded heating elements and temperature-sensing ports, paired with suspended, thermally insulated support columns to evenly distribute molten material to each hot runner nozzle, ensuring consistent filling across all cavities. Additionally, thermal expansion gaps are incorporated to prevent material leakage caused by high-temperature extrusion.

Hot Nozzle Assembly

This assembly is divided into two main categories: open-type and needle-valve-type. The open-type design is simple and has low maintenance costs; the needle-valve-type is equipped with a carbide valve needle and guide sleeve, using a pneumatic cylinder to mechanically seal the gate, thereby eliminating drips, stringing, and gate marks. Hot nozzles come standard with ultra-thin heating rings, independent K-type thermocouples, ceramic insulating spacers, and high-temperature copper sealing gaskets, ensuring precise temperature control and minimizing heat loss.

Drive Components (Exclusive to Needle Valve Systems)

Pneumatic cylinders, valve needle push plates, air fitting connectors, and solenoid valves form a complete drive unit, supporting synchronized opening/closing and time-delay control to optimize weld lines and warpage defects in long plastic parts; for clean production environments, an electric servo drive is available as an option, eliminating the need for an external air source.

Temperature Control Equipment

Multi-channel PID intelligent temperature control cabinet, with one independent temperature control loop per nozzle, offering a temperature control accuracy of ±1°C and integrated fault alarms for over-temperature, open circuits, and short circuits. Comes with high-temperature aviation connectors, metal-braided protective sleeving, and junction boxes for easy installation and removal, suitable for long-cable routing in large molds.

Core Product Advantages

Saves raw materials and eliminates sprue waste, significantly reducing engineering plastic production costs while eliminating the need for sprue grinding and recycling processes;

Shortens the molding cooling cycle, increases single-machine output, and supports continuous production on automated assembly lines;

Lower melt pressure loss ensures smoother filling of thin-walled and long-run parts, reducing the load on the injection molding machine;

The needle valve design ensures products are free of gate marks, eliminating the need for manual sanding and trimming, and improving the appearance yield of finished products;

Zone-specific constant temperature control prevents localized cold spots in the runner, reducing molding defects such as short shots, air bubbles, carbon buildup, and yellowing;

Modular standard components allow for the replacement of individual damaged parts, facilitating future maintenance.

Suitable Materials

PP, PE, ABS, PS, POM, PA, PC, PMMA, LCP, PEEK, glass-fiber/mineral-reinforced materials, flame-retardant plastics, and medical-grade plastic resins with no leaching.

Application Industries

High-volume injection molds for automotive parts, new energy insulation plastic parts, consumer electronics housings and connectors, medical consumables, optical lenses, thin-walled packaging containers, home appliance exterior components, precision gears, and micro-components for daily chemical products.

Selection Guide

General internal structural parts, limited budgets, and mass production of general-purpose plastics: Select an open hot runner system;

High-gloss housings, transparent parts, medical products, and applications requiring flawless appearance: Select needle-valve hot runner systems;

Multi-cavity molds, very small parts, and densely arranged cavities: Select a close-pitch needle-valve system;

Standard batches of small-to-medium-sized plastic parts, stable mass production with 8/16 cavities per mold: Select a balanced needle-valve system with one sprue feeding multiple cavities;

Large, elongated plastic parts where multi-point feeding is prone to causing weld lines: Use a time-sequenced needle valve hot runner system.