Uneven distribution of blowing agent

The cell size in the core is uneven. When this defect occurs in products of Process No. 2, 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. Mold design factor: The blowing agent is unevenly dispersed in the raw material, the mixing energy is insufficient, the blowing agent gasifies during the filling process, and the mold temperature is uneven.

1. Process parameter optimization and adjustment: Stir in the storage tank to ensure uniform dispersion, increase the mixing energy, control the filling pressure to prevent gasification, and make the mold temperature uniform. 2. Systematic troubleshooting method: RIM problem troubleshooting follows the order of "formulation -> mixing -> temperature control -> equipment". First check the two-component ratio and catalyst dosage, then check the mixing head and self-cleaning function, next troubleshoot the raw material and mold temperature control, and finally check the accuracy of the metering pump and hydraulic system. 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 uneven distribution of blowing agent in the RIM process, and the core of the solution lies in ensuring the precise ratio and sufficient mixing of the two components, while controlling the reaction temperature and curing conditions within the optimal window. It is recommended to start troubleshooting from the mixing system and metering accuracy.