Does porosity in electronic communication die castings affect sealing performance?
Publish Time: 2025-10-29
In the manufacturing of electronic communication equipment, electronic communication die castings are widely used in key components such as walkie-talkie housings, base station protective enclosures, and switch structural supports. Their functions extend beyond structural support, encompassing environmental protection, electromagnetic shielding, and thermal management. Sealing performance is a core requirement for ensuring stable operation under complex conditions, especially in outdoor or harsh environments where effective prevention of external intrusion such as moisture, dust, and salt spray is essential. However, the inherent characteristics of the die casting process make porosity a difficult-to-avoid internal defect. These microscopic defects, though small, can have a profound impact on overall sealing performance.The die casting process relies on high pressure to rapidly inject molten metal into the mold cavity, which then solidifies within a short time. This high-speed filling method easily traps air or releases gases generated by mold release agents. If the venting system is poorly designed, these gases can become trapped inside the metal, forming dispersed or concentrated pores. These pores are typically tiny, unevenly distributed, and may exist beneath the surface of the casting or deep within its interior. From the outside, the casting may appear flawless, but it contains potential interconnected channels internally. When multiple pores approach each other or form a chain-like distribution along the wall thickness, they can create penetrating microporous paths, becoming potential channels for external environmental media to seep into the device.For communication equipment housings requiring IP protection ratings, sealing performance depends not only on rubber seals or gaskets in the structural design but also on the inherent tightness of the housing itself. If interconnected pores exist within electronic communication die castings, even with an intact external seal, moisture or corrosive gases can slowly permeate through these microchannels under long-term use or pressure variations. This permeation process is difficult to detect but gradually leads to internal circuitry dampness, component corrosion, and decreased insulation performance, ultimately causing signal interference, short circuits, or even equipment failure. Especially in environments with large temperature differences, pressure changes within the internal cavities exacerbate this "breathing effect," further promoting the intake of external media.Furthermore, the presence of pores affects the effectiveness of subsequent surface treatment processes. Many communication equipment housings require spraying, electrophoresis, or anodizing to enhance corrosion resistance and appearance. If the substrate contains pores, the treatment fluid may be trapped within the pores during the drying process, slowly releasing over a long period, leading to blistering, peeling, or localized corrosion of the coating. This not only weakens the integrity of the protective layer but may also damage the adhesion of the sealing interface, indirectly affecting overall sealing performance.It is worth noting that not all pores cause leakage. Isolated, closed, and small pores far from critical sealing areas usually do not directly affect functionality. The key issue lies in the distribution, morphology, and connectivity of the pores. Near critical pressure-bearing or sealing mating surfaces, even a small number of connectivity defects can become the starting point of failure. Therefore, the limitations of the die-casting process should be fully considered during the design phase to avoid excessively thin or complex wall thicknesses in the sealing area, reducing the risk of gas entrapment.To reduce the impact of pores on sealing performance, the manufacturing process needs to be controlled at multiple stages. Optimizing the mold's gating system and venting design, and appropriately setting overflow channels and venting channels, helps guide gas out smoothly. Using vacuum die-casting technology, air can be removed from the mold cavity before filling, significantly reducing pore formation. Meanwhile, precisely controlling the degassing process during alloy smelting to reduce the gas content of the molten metal is also an effective way to improve the density of castings. Furthermore, non-destructive testing of key components, such as X-ray flaw detection or penetrant testing, can effectively identify potential defects and ensure product quality.In conclusion, although porosity in electronic communication die castings is a process byproduct, its impact on the sealing performance of electronic communication equipment cannot be ignored. It can become a hidden channel for environmental media intrusion, threatening the long-term reliability of the equipment. Only through the coordinated management of material selection, process optimization, and quality control can the hazards of porosity be effectively suppressed, ensuring that the die-cast shell continues to provide reliable sealing protection in harsh environments.
