Cold Runner Mold: Plastic Injection Molding, Simple Part Design, Limited Production Runs, Low Maintenance, Change Production Color, Low-Cost Mold

What is cold runner mold

A cold runner mold is a type of injection molding tool where the plastic material is cooled in a separate channel or “runner” before it reaches the individual cavities of the mold. The plastic resin is injected into the cold runner system, where it solidifies before being directed into the cavities to form the final parts. The term “cold” refers to the fact that the runner system is not heated, unlike a “hot runner” mold. Cold runner molds are often used for producing large numbers of small, simple parts and are relatively low-cost to produce.

SINCERE TECH (plasticmold.net) provides plastic injection mold solutions to industries of all types and sizes.

Our state-of-the-art mold building facilities include high-speed CNC Milling and mirror EDM Machining for many types of complex specialty injection molds, including insert molds, gas-assist injection molding, 2K mold, multiple cavities mold and unscrewing molds. We can build molds from small to big (25 ton) for both hot runner mold systems and cold runner mold systems.

Cold Runner Molds: Efficient and Economical

Here are some key characteristics and considerations of cold runner molds:

1. Runner System: In a cold runner mold, the plastic material is injected into a runner system that distributes the molten plastic to multiple mold cavities. The runner system is typically designed to be easily removed from the finished part, but it generates waste material (the runners) that needs to be recycled or disposed of.
2. Simplicity: Cold runner molds are simpler and less expensive than hot runner molds because they do not require the complex heating and control systems associated with hot runners.
3. Material Waste: The main drawback of cold runner molds is the generation of material waste. The runners are typically discarded or recycled, which can add to material costs.
4. Cycle Time: Cold runner molds may have slightly longer cycle times compared to hot runner molds because the plastic in the runners must cool and solidify before the parts can be ejected.
5. Part Quality: The simplicity of cold runner molds can make them a good choice for parts with relatively simple geometries. However, in some cases, cold runners can cause aesthetic defects like visible weld lines on the finished parts.
6. Heat-sensitive Materials: Cold runner molds are suitable for a wide range of plastics but may be less suitable for heat-sensitive materials that can degrade during the cooling process.
7. Maintenance: Maintenance and cleaning of cold runner systems are generally easier compared to hot runners because there are no heated components to deal with.

Ultimately, the choice between cold runner and hot runner molds depends on the specific requirements of the molding project, such as part complexity, material selection, production volume, and cost considerations. Cold runner molds are commonly used in many applications, particularly when cost and simplicity are important factors.

Choosing the correct system depends on the requirements of the part to be produced. A few of the considerations include:

• Part complexity
• Color requirements
• Physical characteristics of the material
• Type of material – virgin or “regrind”
• Color changes during the production run

Cold runner systems are best used:

• When the parts produced are of simple design,
• For limited production runs, or
• When a rapid change in production colour is needed

In a cold runner mold, the runner (excess material retained in the feed channels) is cooled and ejected with the part. Every cycle, apart, and a runner is produced.

There are two major types of cold runner molds:

• A two-plate cold runner mold is the easiest and least expensive type of mold to produce. Two plate molds have a single parting plane, and the mold splits into two halves at the plane. Because the runner system must be in line with the parting plane, the part can only be gated on its perimeter.
• A three-plate cold runner mold differs from a two plate in that it has two parting planes, and the mold splits into three sections every time the part is ejected. This feature provides greater flexibility of design, allowing gating to be placed in the most efficient locations. Since the mold has two parting planes, the runner system can be located on one, and the part on the other, for easier separation.

Cold Runner Mold Systems: The advantages & disadvantages

There are many significant advantages to using a cold runner mold system:

• Simple, lower-cost mold design and construction
• Considerably less expensive than a hot runner system
• Moulds require less maintenance
• Easier to set up and operate
• Colour changes are easy – all plastic in the mould is ejected with each cycle

While it is a less expensive process that hot runner systems, there are a few disadvantages to cold runner systems that need to be considered, including:

• Waste plastic generated
• Runner material must be either disposed of or
  reground and reprocessed
• Additional steps in the manufacturing process
• Regrind will increase variations in the injection 
  molding process
• Regrinding could decrease the plastic’s strength characteristics and mechanical properties

At Sincere Tech China mold maker, our unwavering commitment to staying at the forefront of the plastic mold industry drives us to embrace advancements and anticipate future trends. We continuously explore innovative materials and composites that offer enhanced performance and promote sustainability. By investing in ongoing research and development, we consistently deliver cutting-edge solutions that meet the evolving needs of our valued customers. As a trusted injection mold supplier in China, we take pride in our unwavering dedication to excellence.

Aligned with our sustainability goals, we place a high priority on environmentally friendly practices. We actively seek out sustainable alternatives, such as biodegradable polymers, and implement recycling initiatives to minimize the environmental impact of our manufacturing processes. By choosing our custom injection molding services, you can align your brand with sustainable manufacturing practices and contribute to a greener future.

Ensuring quality is our topmost priority, and we maintain rigorous quality control measures throughout the entire manufacturing process. Equipped with state-of-the-art facilities and staffed by skilled technicians, we subject each product to thorough inspection and testing. This guarantees exceptional performance, reliability, and customer satisfaction.

When you choose Sincere Tech as your preferred plastic mold maker in China, you can expect the highest level of professionalism, expertise, and innovation. Our dedicated team is committed to helping you bring your ideas to life, delivering superior products that excel in performance, durability, and cost-effectiveness.

Partner with Sincere Tech today and experience our relentless pursuit of excellence, as we work together to bring your vision to reality.

Our expanded capabilities include:

1. Rapid Prototyping: We offer rapid prototyping services to quickly transform your concepts into tangible prototypes, allowing for iterative design improvements and accelerated product development.
2. Precision Tooling: Our advanced tooling capabilities enable us to create high-quality molds with tight tolerances, ensuring consistency and precision in your injection-molded products.
3. Overmolding: We specialize in overmolding, which allows for the combination of multiple materials or components, resulting in enhanced functionality, aesthetics, and durability.
4. Insert Molding: Our expertise in insert molding enables us to securely encapsulate inserts within the molded parts, facilitating efficient assembly and enhancing product performance.
5. Two-Shot Molding: With two-shot molding, we can produce complex, multi-material components in a single operation, reducing assembly requirements and enhancing design possibilities.
6. Value-Added Services: In addition to injection molding, we offer a range of value-added services, including product assembly, packaging, and logistics support, streamlining your supply chain and reducing costs.

Partner with Sincere Tech Mould suppliers for your custom injection molding needs, and benefit from our comprehensive capabilities, unwavering commitment to quality and sustainability, and our drive to exceed your expectations at every step of the process. Together, let’s bring your innovative ideas to life.