Non-return ring stuck

The non-return ring cannot close, causing serious material leakage during injection. When this defect occurs in products of Process No. 1, it is usually related to a specific process parameter range or equipment status. If it persists, it will directly affect the product qualification rate and production cycle, increasing material loss and rework costs. Timely diagnosis and elimination is a basic requirement to ensure stable production.

1. Equipment factor: The fitting clearance between the non-return ring and the screw head is too small, foreign matter gets stuck in, the non-return ring is overheated and deformed, and burrs are produced by long-term wear. 2. Temperature factor: The settings of barrel temperature and mold temperature directly affect melt flowability, cooling rate, and crystallization behavior; relatively low temperature is a common cause of filling and molding quality problems, and precise control is required according to the material's recommended processing window. 3. Mold comprehensive factor: In addition to venting, mold design parameters such as the cooling water circuit layout, gate position and size, and draft angle all have a systematic impact on product quality, and optimization is needed from the source of mold design.

1. Process parameter optimization and adjustment: Adjust the fitting clearance, clean out foreign matter, check the cooling condition, and replace the worn non-return ring. 2. Systematic troubleshooting method: Troubleshoot item by item in the order of "parameters -> materials -> mold -> equipment". First adjust the parameters that are easiest to change, such as injection pressure and temperature, and observe the effect; if there is no improvement, check the drying and flowability of the raw material; further check the mold venting and gate design; finally check the mechanical state of the equipment (non-return ring, screw). Change only one variable at a time to determine the root cause. 3. Preventive management: Establish standardized process parameter cards and quality control limits for each mold/product, and regularly conduct process capability index (CPK) assessments. For recurring problems, use fishbone diagrams or 5Why analysis to trace the root cause, and solidify countermeasures as PFMEA control points.

This problem is a typical manifestation of non-return ring stuck in '2079851475616104452, and the core of the solution lies in eliminating the root cause of the defect through systematic optimization of process parameters (temperature, pressure, speed) and rationality checks of mold design. It is recommended to start with process parameter adjustment and gradually go deeper to the equipment and mold levels.