Hot Runner Injection Molding Supplier In China

Maximize Your Savings with a Trusted hot runner Injection Molding Partner

Hot Runner Injection Molding Manufacturer

Stebro Mold is a professional hot runner injection molding supplier in China, we use the Engel multi-shot injection molding machine to produce high-quality 2K plastic components. You won’t have to contact multiple providers when you work with us. You can have the advantage of a single-source plastics provider from idea to shelf.

Our services include:

  • 2D & 3D product design and optimization
  • The material selection
  • Rapid prototyping services
  • Cost-effective 2K mold solution
  • Mold Flow Analysis to optimize the mold design
  • In-house 2K mold manufacturing, tooling transfer, mold change, and maintenance
  • 2K mold trial
  • Pre-production runs and mass production
  • Part Assembly

We’re here to make sure your projects are a success! With our help, you’ll get 2K injection molded parts done correctly from the start, within your budget, and on time.

Why Stebro Mold for Hot Runner Molding Supplier

Customer Letters
Amanda Lee
CEO & Founder Crix
Catherine Gilbert
Director at Initech

What is a hot runner system in injection molding?

A hot runner system in injection molding is a set of heated parts within an injection mold.

It can keep plastic material molten as it moves from the injection molding machine to the mold cavity. It delivers molten plastic to the mold cavity efficiently and precisely. It reduces waste and improves the quality of molded parts while decreasing the time it takes to create each part.

Many hot runner injection molding suppliers prefer hot runner systems for high-volume production.

Hot runner brands and manufacturer

Advantages of hot runner injection molding system

  • Reduced cycle time
  • Material and energy savings
  • Improved part quality
  • Reduced labor costs
  • Greater design flexibility
  • Less scrap and waste
  • Elimination of knit lines

Disadvantages of plastic injection molding hot runner

  • Higher initial investment
  • Increased complexity
  • Maintenance and cleaning challenges
  • Potential limitations with certain materials
  • Risk of thermal expansion
  • Higher energy consumption

Key components of a hot runner system

  • Hot Manifold
  • Hot runner nozzles
  • Gates
  • Heaters
  • Temperature controllers
  • Thermocouples
  • Wiring and connectors
  • Seals and gaskets
  • Mounting and support components

Types of hot runner systems

  • Externally Heated Hot Runner Systems
  • Internally Heated Hot Runner Systems
  • Open Gate Hot Runner Systems
  • Valve Gate Hot Runner Systems
  • Single Temperature Control Hot Runner Systems
  • Multi-Zone Temperature Control Hot Runner Systems

Injection molding hot runner design

  • Understand your application requirements: Analyze the molding application, such as part size, weight, surface finish, production volume, plastic material and color. This helps identify the ideal hot runner system configuration and features.
  • Material properties: Review the thermoplastic’s properties, such as viscosity, melting temperature, and thermal sensitivity. Choose a hot runner system that maintains proper processing conditions and meets material requirements to prevent issues like degradation or leakage.
  • Mold design and cavity layout: Consider the cavity number, mold layout, and the flow balance. This will ensure even filling and consistent part quality.
  • Manifold design: The manifold distributes molten plastic to hot runner nozzles. Its design should ensure even flow distribution, minimal pressure drop, and desired temperature maintenance. Also, consider ease of maintenance, cleaning, and thermal expansion.
  •  Nozzle design and selection: The nozzle design should based on application requirements and desired molten plastic flow control. Optimize nozzle length, diameter, and tip geometry for ideal flow rate and minimal pressure drop. Ensure nozzle material and design compatibility with the thermoplastic for durability and wear or corrosion resistance.
  • Gating method: Pick a gating method based on application requirements and desired molten plastic flow control. Consider gate location, size, and shape to influence filling patterns, pressure requirements, and finished part appearance.
  • Heating and temperature control: Choose a heating method (external or internal) and temperature control strategy for consistent processing conditions. Consider multi-zone temperature controllers for improved accuracy, especially in complex or sensitive applications.
  • System integration and compatibility: Verify hot runner system compatibility with your injection molding machine and mold design. Consider mounting hardware, wiring, connectors, and machine control system suitable for seamless integration and minimal downtime.
  • Ease of maintenance and cleaning: Choose a hot runner system designed for easy maintenance and cleaning. Accessibility, disassembly ease, and materials that withstand cleaning processes without damage are crucial.
  • Budget and return on investment: Determine if the hot runner system offers the best ROI for your application.
  • Vendor selection: Research and compare hot runner system manufacturers based on reputation, product quality, technical support, and after-sales service. Work with a vendor that provides support and expertise throughout the selection, installation, and maintenance process.

By considering these factors and collaborating with an experienced hot runner injection molding company, you can improve efficiency, part quality, and overall cost savings for your project.

cold runner VS hot runner injection molding process

Cold Runner System:

  • Cold runner molds use unheated channels (runners) for molten plastic flow. Plastic cools and solidifies in channels.
  • After the molding and ejection, the solidified plastic in the runner system must be separated from the finished parts. It can be reground and reused or discarded.
  • Longer cycle times due to additional cooling time
  • Less expensive to set up and maintain
  • Easier material changes, suitable for low-volume production runs and frequent material changes.
  • Works better with certain materials such as elastomers and high temperature thermoplastics. These materials may be sensitive to the prolonged exposure to heat in hot runner systems.

Hot Runner System:

  • In hot runner injection molding, the plastic melt flows through melt channels (manifolds and nozzles) before entering the mold cavities. The system maintains the plastic in its molten state, preventing it from solidifying within the heated runners. If the hot runner system with manifold, it need one more mold plate for the hot runner.
  • Hot runner injection molding systems eliminate the need for separating solidified plastic from the finished parts, as there is no waste material generated in the runner channels. This results in reduced material waste and cost savings.
  • Hot runner systems generally have a shorter cycle time compared to cold runner systems, as there is no need to wait for the plastic in the runner channels to solidify. This increases overall production efficiency and can lead to higher throughput.
  • Hot runner systems are more expensive to set up and maintain due to their more complex design, heating elements, and temperature controllers. However, they can provide cost savings over time through reduced material waste and improved cycle times.
  • Material changes can be more challenging in hot runner systems, as residual material can remain in the heated channels, leading to contamination or degradation. This makes hot runner systems more suited to high-volume production runs with fewer material changes.
  • Hot runner systems are ideal for use with a wide range of thermoplastic materials that are not sensitive to prolonged exposure to heat. They can provide better control over material flow, temperature, and pressure, leading to improved part quality and reduced defects.

Choosing between cold runner and Hot runner injection molding depends on application requirements, material properties, production volume, and budget. Cold runner molds are simpler and cheaper but generate more waste and have longer cycle times. Hot runner molds boost efficiency, minimize waste, and improve part quality but incur higher setup and maintenance costs. Contact with the hot runner injection molding manufacturers to get the best solution.

Troubleshooting common hot runner issues

  • Material leakage: Material leakage can occur around the nozzle, manifold, or gate areas, leading to part defects and material waste. To troubleshoot this issue, check for proper sealing, alignment, and nozzle/manifold temperature. Ensure that all components are assembled correctly and that there is no damage to sealing surfaces or o-rings.
  • Poor temperature control: Inconsistent or inaccurate temperature control can cause issues such as material degradation, stringing, or flow imbalances. To resolve this issue, verify the function of temperature controllers, heaters, and thermocouples. Replace any faulty components and ensure proper calibration of temperature control equipment.
  • Gate freezing or sticking: If the gate freezes prematurely or sticks during operation, it can result in short shots, poor part quality, or increased cycle time. To troubleshoot, check the gate design, gate size, and processing conditions. Adjust the nozzle or gate temperature as needed and ensure proper material flow and cooling times.

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