Insufficient filling/material shortage

The end of the product is not filled or there is a local material shortage. When filling is insufficient, the product shows obvious material missing at the end of the cavity or at the thinnest wall, and the edge of the shortage is smooth or irregularly shaped. Similar to the short shot of '2079851475616104452, but in compression molding and transfer molding, insufficient filling may also be directly related to the feeding position and feeding method——if the material is unevenly distributed in the mold, local material shortage will occur even if the total amount is sufficient. Products with insufficient filling cannot be used, and their local unfilled areas of the mold will cause the flow pattern of the next molding to change.

1. Process parameter factors: insufficient feeding amount, poor material flowability, insufficient molding pressure, mold closing speed too fast and venting not in time. 2. Preheating factor: The preheating temperature and time of the material (especially thermosetting molding compounds) directly affect its flowability and curing behavior; improper preheating will lead to poor filling or uneven curing, and it is a key control point unique to compression molding.

1. Process parameter optimization and adjustment: increase the feeding amount, improve material flowability (preheat or raise the mold temperature), increase the molding pressure, adjust the mold closing speed. 2. Systematic troubleshooting method: Troubleshooting of compression molding problems follows the order of 'material -> temperature -> pressure -> mold'. First check the preheating and flowability of the material, then verify the mold temperature distribution and curing time, then adjust the molding pressure and mold closing speed, and finally check the mold venting and demolding conditions. 3. Preventive management: Establish standardized process parameter cards and quality control limits for each set of mold/product, and regularly conduct process capability index (CPK) evaluations. For recurring problems, use fishbone diagrams or 5Why analysis to trace the root cause, and solidify the countermeasures as PFMEA control points.

This problem is a typical manifestation of insufficient filling/material shortage in compression molding; the core of the solution lies in proper preheating of the material and assurance of flowability, as well as precise matching of mold temperature and molding pressure. It is recommended to adjust coordinately from both aspects of material state and process parameters.