What is the reason why the main channel sticks to the mold during injection molding

Table of Contents


Unresolved adhesion issues can lead to production downtime, scrapped parts and increased maintenance costs. Addressing these issues is important to ensure smooth operations, maintain high product quality, and maximize overall efficiency. We will delve into the reasons and solutions for the main channel sticking to the mold during injection molding.

Injection molding is often used for mass production of injection molded parts, which can greatly improve production efficiency. Injection molding is a molding process that produces parts by injecting its molten form into a mold. After cooling and hardening, the final product takes on the shape of the mold. Injection molding is often used for mass production of parts.

During the production process, we often encounter the problem of the main channel sticking to the mold. Now I will study how to solve this problem and improve production efficiency.

II. Understanding the Causes of Main Channel Sticking

Temperature Discrepancies

Impact of Mold Temperature on Sticking

Mold temperature plays a crucial role in the sticking phenomenon.

Significant differences between temperature difference between the mold temperature and the material’s melt temperature can lead to adhesion issues.

Influence of Melt Temperature on Adhesion

The temperature back pressure at which the material is melted also affects sticking.

High plastic melt down temperatures combined with lower mold temperatures exacerbate adhesion, increasing the likelihood of sticking in the mold.

Poor Mold Release Agents

Importance of Effective Release Agents

Proper application of release agents is essential for preventing sticking.

Effective release agents create a barrier between the mold surface and the material, facilitating smooth molded part release.

Consequences of Inadequate Application or Degradation

If release agents are applied inadequately or degrade over time, they may fail to provide sufficient protection against sticking.

Inadequate coating on mold surfaces can result in adhesion and sticking, leading to production issues.

C. Surface Roughness

Effects of Uneven or Rough Mold Surfaces

Mold surface roughness directly impacts the mold plates likelihood of sticking.

Uneven or rough surfaces provide more opportunities for material adhesion, increasing the risk of degraded materials sticking.

Strategies for Achieving Optimal Surface Finish

Proper surface finishing techniques, such as polishing, are essential for minimizing sticking.

Achieving optimal surface finish ensures smooth mold surfaces, reducing the likelihood of material adhesion and sticking.

D. Material Properties

Role of Material Selection in Sticking Tendencies

The choice of material significantly influences its sticking behavior.

Certain materials exhibit higher viscosity or reactivity with mold surfaces, increasing the likelihood of sticking.

Considerations for Materials with High Viscosity or Reactivity

Materials with high viscosity or reactivity may stick and require special attention to prevent sticking.

Understanding the properties of selected materials is crucial for mitigating sticking issues during injection molding.

E. Injection Pressure and Speed

Effects of Excessive Pressure and Speed on Adhesion

Injection pressure and speed impact the material’s interaction with the mold surfaces.

Excessive pressure high melt temperature or turbulent flow speed can force the material to adhere tightly to the mold, increasing the risk of sticking.

If the injection molding pressure is unstable or too small, it will cause problems in the filling and compaction process of the plastic in the mold, increase the friction between the mold surface and the plastic, and cause mold sticking.

Importance of Precise Control of Injection Parameters

Precise control of injection parameters, including pressure and speed, is essential for minimizing sticking.

Optimizing injection processing parameters helps maintain proper material flow and release, reducing the likelihood of sticking.

F. Mold Design

Impact of Design Elements on Material Flow and Release

Mold design features influence melt flow pattern and release during injection molding.

Factors such as draft angles, venting systems, cycle time and cooling time can affect sticking tendencies.

Strategies for Designing Molds to Minimize Sticking

Well-conceived mold designs with appropriate features facilitate smooth material release and minimize sticking.

Designing molds with meticulous attention to detail helps mitigate sticking issues and ensures efficient production.

III.Main channel sticking mold solution

A. Optimizing Mold Temperature

Proper mold temperature is crucial for preventing plastic parts sticking in injection molding.

Optimal temperature control systems help maintain consistent mold temperatures throughout the process.

Regular monitoring and adjustment of mold temperatures based on material requirements and production conditions are essential.

B. Enhancing Surface Finish

Improving surface finish through polishing and surface treatment reduces the likelihood of sticking.

Utilizing advanced surface finishing techniques, such as chemical etching or electroplating, can further enhance mold surface smoothness.

Regular maintenance and cleaning of mold surfaces help preserve optimal surface finish and prevent mold filling from sticking.

C. Selecting Suitable Materials

Choosing materials with low viscosity and minimal reactivity with mold surfaces reduces sticking tendencies.

Conducting material compatibility tests and selecting mold release agent can enhance material flow and release.

Collaborating with material suppliers to identify suitable materials for specific injection molding applications is essential.

D. Refining Injection Parameters

Fine-tuning injection parameters, including pressure, the injection speed amount, and temperature, helps minimize sticking.

Conducting thorough process optimization studies and adjusting parameters based on material behavior and mold conditions are critical.

Implementing real-time monitoring systems to track injection parameters and identify potential sticking issues early in the injection process, is beneficial.

E. Designing Molds with Attention to Detail

Incorporating design features that facilitate smooth material flow and release is essential for dimensional stability and minimizing sticking.

Ensuring proper draft angles, ejector pins, sprue bushing,venting systems, Mold opening device and gating configurations promote efficient mold cavity filling and part ejection.

Collaborating with experienced mold designers and leveraging advanced design software tools can help optimize mold design for minimal sticking.

By implementing these solutions and best practices, manufacturers can effectively address sticking issues in the injection molding process, ensuring smooth production operations and high-quality molded parts. Proactive measures, continuous monitoring, and ongoing optimization are key to preventing part sticking and maximizing overall efficiency in injection molding processes.


Proactive measures such as optimizing mold temperature, refining injection parameters, and enhancing mold design are critical to preventing adhesion.By addressing potential adhesion issues before they occur, manufacturers can minimize production downtime and reduce the risk of part defects.

Emphasis on effective problem solving and optimization strategies is critical to achieving seamless production and high-quality molded parts.Continuous monitoring, process optimization, and collaboration among stakeholders are key to effectively identifying and solving tough problems.

By prioritizing problem solving and optimizing efforts, manufacturers can streamline production processes, improve product quality, and increase overall efficiency.

In summary, solving tough problems in injection molding requires a comprehensive approach that includes proactive measures, effective problem solving, and optimization strategies. By employing these methods, manufacturers can overcome tough challenges, ensure production operations run smoothly and deliver high-quality molded parts to meet market demand.

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