Die Casting Defects And Their Causes, Methods To Avoid Die Casting Defects

Die casting defects vary. Here are some common die casting defects and their possible causes:
There are patterns or traces of metal flow on the surface of the casting: This may be because the flow channel leading to the inlet of the casting is too shallow, or the injection specific pressure is too high, causing the metal flow rate to be too high, causing splashing of molten metal.
There are small protrusions on the surface of the casting: This may be due to a rough surface or foreign matter on the surface of the mold, which prevents the molten metal from flowing smoothly during the cooling process.
There are cracks or local deformations on the surface of the casting: The possible reasons are that the ejector rods are unevenly distributed or insufficient in number, resulting in uneven stress; the ejector rod fixed plate is deflected during operation, resulting in uneven stress; the wall of the casting is too thin and shrinks After deformation.
There are pores on the surface of the die casting: This may be due to the use of too much lubricant, or the gas is not completely discharged during the die casting process.
There are shrinkage cavities on the surface of the casting: This is usually because the die-casting process is unreasonable and the wall thickness changes too much, causing the metal to shrink unevenly during the cooling process.
The outer contour of the casting is not clear, the shape cannot be formed, and there is a partial shortage of material: This may be because the pressure of the die-casting machine is not enough, the injection specific pressure is too low, or the temperature of the molten metal is too low and the fluidity is poor.
The casting part is not formed and the cavity is not fully filled: the reasons may include the temperature of the die-casting mold being too low, the temperature of the molten metal being too low, the press pressure being too small, the molten metal being insufficient, the injection speed being too high, and the air not being able to be discharged.
Cold separation: refers to the phenomenon that metal flows with lower temperature are connected to each other without fusion and gaps appear, which may appear as blackening, accompanied by flow marks or surface bubbles.
Scratches: Refers to the scratch marks on the surface of the casting due to metal adhesion and too small a slope in mold manufacturing along the demoulding direction, and even cracks in severe cases.