Shrinkage cavities (also known as sinkage) in die castings are a common defect that usually occurs in thick-walled or densely populated areas of the part. Such defects may affect the mechanical properties and appearance of the part. The following are some common causes of shrinkage cavities in die castings and their corresponding solutions:

1.Insufficient filling of metal liquid:

Cause of the problem: The metal liquid failed to completely fill the mold cavity during the filling process, causing shrinkage cavities to form in some areas.

Solution: Adjust the pouring system and pouring parameters, increase the pouring opening or change the pouring direction to promote metal filling and improve the filling rate and fullness.

2. Mold design issues:

Cause of the problem: Improper mold design, such as an overly thick or overly complex structure, may cause the metal liquid to be hindered during the filling process and form shrinkage cavities.

Solution: Optimize the mold design, reduce the thick-walled parts of the part, add ventilation holes or improve the gating system to promote the filling and flow of metal liquid.

3. Improper temperature control of metal liquid:

Cause of the problem: If the temperature of the metal liquid is too high or too low, it may cause poor fluidity of the metal liquid during the filling process and easily form shrinkage cavities.

Solution: Strictly control the pouring temperature of the metal liquid to ensure that it is poured within a suitable temperature range and avoid the temperature being too high or too low.

4. Organizational structure issues of metal alloys:

Cause of the problem: The chemical composition of the metal alloy is uneven or there are other impurities, which may cause the metal liquid to solidify unevenly during the filling process and form shrinkage cavities.

Solution: Optimize the formula of metal alloys, strengthen the stirring and homogenization of metal liquids, and ensure that the organizational structure of metal alloys is uniform and stable.

5. Improper operation:

Cause of the problem: Improper control by the operator during the die-casting process, such as excessive pressure, temperature or speed, may also cause the metal liquid to form shrinkage cavities during the filling process.

Solution: Train operators to ensure they understand and correctly implement operating procedures, strictly control die-casting parameters, and avoid operating errors.

Through the above measures, shrinkage cavities in die castings can be effectively prevented and reduced, and the quality and reliability of die castings can be improved.