Overpacking

The part is too thick or flash is severe. When filling is insufficient, the part shows obvious material shortage at the end of the cavity or at the thinnest wall thickness, with smooth or irregular shortage edges. Similar to short shot in '2079851475616104452, but in compression and transfer molding, insufficient filling may also be directly related to the charging position and charging method — if the material is unevenly distributed in the mold, local material shortage will occur even if the total amount is sufficient. Parts with insufficient filling cannot be used, and their local unfilling of the mold will cause the flow pattern of the next molding to change.

1. Process parameter factors: excessive holding pressure, excessive holding time, excessive injection volume, insufficient clamping force. 2. Temperature factors: the settings of barrel temperature and mold temperature directly affect melt fluidity, cooling rate, and crystallization behavior; 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 factors: in addition to venting, mold design parameters such as cooling water channel layout, gate position and size, and demolding draft angle all have a systematic impact on part quality, and optimization is required from the source of mold design.

1. Process parameter optimization and adjustment: reduce holding pressure, shorten holding time, reduce injection volume, increase clamping force. 2. Systematic troubleshooting method: troubleshoot item by item in the order of "parameters -> material -> 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 fluidity of the raw material; further check mold venting and gate design; finally check the mechanical condition of the equipment (check 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) evaluation. For recurring problems, use fishbone diagram or 5Why analysis to trace the root cause, and fix the countermeasures as PFMEA control points.

This problem is a typical manifestation of overpacking in '2079851475616104452; 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 into the equipment and mold levels.