Frequent porosity, cold shuts, and deformation in die-cast parts? Detailed explanation of the main defect causes and process optimization solutions.
Jun 12, 2026
In the mass production of aluminum die casting and zinc die casting, defects such as porosity, shrinkage cavities, cold shuts, flow marks, product warping, and edge burrs have long plagued major manufacturers. Defective products not only increase raw material waste and rework costs but also delay order delivery, impacting long-term cooperation between suppliers and customers. Especially for high-end components in new energy, 3C electronics, and precision instruments, where stringent requirements exist for internal density, appearance, and dimensional tolerances, defect control has become a key indicator of a die casting plant's core competitiveness.
Porosity and shrinkage cavities are the most common defects in die casting. Incomplete degassing during raw material melting, insufficient mold venting design, excessive fluctuations in pouring temperature, and improper matching of filling speeds can all lead to gas trapping within the molten metal, forming porosity. Meanwhile, significant variations in product wall thickness, uneven cooling system distribution, and inconsistent solidification shrinkage can easily result in shrinkage cavities. Targeted improvement methods generally include thorough preheating and drying of raw materials, optimization of mold venting structure, segmented adjustment of injection parameters, and balanced mold cooling water channel design, reducing the proportion of void defects from the molding source.
Thin-walled shell products are prone to cold shuts, which are essentially caused by the low temperature at the fusion of two molten metals, resulting in discontinuous fusion. These appearance defects can be effectively improved by appropriately increasing the mold preheating temperature, optimizing the gate layout, and shortening the filling time. Issues such as warping, demolding scratches, and excessive burrs after die casting are mostly due to the lack of DFM review on the initial drawings, unreasonable draft angle settings, and insufficient parting surface matching accuracy. Professional die casting companies will intervene in structural optimization early in the mold opening process, matching a reasonable draft angle, and cooperating with subsequent automatic edge trimming processes to ensure stable product dimensional consistency.
Currently, competition in the die casting industry is gradually shifting from low-price competition to refined quality control. Systematic defect analysis and rectification capabilities can continuously reduce costs and increase efficiency for downstream customers. Our company undertakes custom die casting business for aluminum alloys and zinc alloys year-round. Our technical team can provide specialized rectification plans for customer samples and mass production defects, and offers free one-stop services including preliminary process prediction, trial production debugging, and mass production quality control. Customers with drawing prototyping and mass production needs are welcome to contact us.
