Common Problems in Die Casting and Improvement Methods

The control of the die cast tooling surface temperature is very important for producing high quality die castings.

Uneven or inappropriate die cast tooling temperature will also cause the size of the casting to be unstable, and the casting will be deformed during the production process, resulting in defects such as thermal pressure, mold sticking, surface depression, internal shrinkage and hot bubbles. When the mold temperature difference is large, the variables in the production cycle, such as filling time, cooling time, and spraying time, will be affected to varying degrees. Here is an introduction to common problems and improvement methods of die-casting molds.

1. Cold mark

Reason: The temperature at the front of the molten soup is too low, and there are traces when they overlap.

Improve methods:

1. Check whether the wall thickness is too thin (designed or manufactured), and the thinner area should be directly filled.

2. Check if the shape is not easy to fill: too far, closed area, blocked area, too small rounded corners, etc. are not easy to fill.

3. Shorten the filling time.

4. Change the filling mode.

5. Increase mold temperature.

6. Increase the temperature of the molten soup.

7. Check the alloy composition of the die casting mold.

8. Enlarging the escape airway may be useful.

9. Adding a vacuum device may be useful.

2. The crack

Reason: shrinkage stress and force cracking during ejection or whole edge.

Ways of improvement:

1. Increase the fillet.

2. Check if there are hot spots.

3. Change the pressurization time.

4. Increase or shorten the clamping time.

5. Increase the draft angle.

6. Increase the ejector pin.

7. Check whether the die-casting mold is misaligned or deformed.

8. Check the alloy composition.

3. Pore

Reason: Air is mixed in the molten soup. The source of the gas: during melting, in the barrel, in the mold, and release agent.

Improve methods:

1. Appropriate slow speed.

2. Check whether the turning of the runner is smooth and whether the cross-sectional area is gradually decreasing.

3. Check whether the area of the escape airway is large enough, whether it is blocked, and whether the location is in the last filling place.

4. Check if the release agent is sprayed too much and the mold temperature is too low.

5. Use vacuum method.