Technical requirements for shrinkage marks in injection molding process of PC rural lighting ready board in Africa

The injection molding of PC material African rural lighting ready board body should eliminate material shortage, obvious shrinkage marks, and surface bubble defects. The depth of shrinkage marks on the exposed surface should not exceed 0.1mm, and the maximum depth of shrinkage marks on the internal non visible structural surface should not exceed 0.15mm. The hand feel should not perceive obvious depressions. This indicator is suitable for outdoor low-voltage distribution enclosures, taking into account appearance, dimensional accuracy, and long-term resistance to UV and temperature deformation, preventing stress concentration at the location of shrinkage marks, and avoiding shell cracking in the large temperature difference environment between day and night in Africa.

PC has a high viscosity, and thick walled areas, reinforcement ribs, and screw column roots are most prone to shrinkage marks. In the injection molding process, a stepped holding pressure is used to increase the holding pressure and extend the holding and shrinkage time. The melt temperature is controlled at 280-310 ℃ and the mold temperature is controlled at 70-100 ℃ to ensure that the material is replenished before the gate solidifies and reduce the risk of depression caused by cooling shrinkage. Optimize the exhaust groove of the mold to prevent trapped gas from causing bubbles. Bubbles are not allowed to appear on the appearance and sealing area of the box. The diameter of bubbles on the internal surface should not exceed 0.3mm, and there should be no more than 3 bubbles per hundred square centimeters.

Strictly prohibit material shortage and insufficient injection. The sealing surface, buckle, installation column and other functional structures of the box must be fully formed, and material shortage will be directly judged as scrap. Inspect from multiple angles at a distance of 30-50cm under natural light, and use a depth gauge to detect shrinkage marks. Excessive shrinkage marks can change the flatness of the box body, affect the clearance between the cover and the box body of the lighting ready board, damage the IP protection level of the lighting ready board, and reduce the service life of the box body in outdoor humid and dusty environments, causing potential leakage hazards. Production requires full inspection of the depth of shrinkage marks on the first piece, and regular sampling during the batch process to ensure adaptability to complex working conditions in African rural areas.