Aluminum Die Casting parts common defects and solutions
The following are some common defects of aluminum die casting process:
1). Cold pattern:
The reason: the front of molten metal temperature is too low, when stacked traces.
1. Check whether the thin wall thickness (design or manufacturing), thinner regions should direct filling.
2. Check whether the shape is not easy to fill; too far away, enclosed area (such as fin (fin), projection), blocked area, rounded etc too easy filling. And note whether there is a rib-point or cold spots.
3. Shorten the filling time. Methods to shorten the filling time: ...
4. Change the fill mode.
5. Increase mold temperature method: ...
6. Raise the temperature of molten metal.
7. Check the alloy composition.
8. Airway may be useful to increase the escape.
9. Vacuum devices may be useful for me.
Reason: 1. Shrinkage stress.
2. Or trimming the top of the crack under stress.
Improve the way:
1. Increase the fillet.
2. Check for hot spots.
3. Pressurization time changes (cold room machine).
4. Increase or shorten the clamping time.
5. Increasing the draft angle.
6. Increase ejector pin.
7. Check whether there is mold dislocation, deformation.
8. Check the alloy composition.
Reason: 1. Air inclusions in molten soup.
2. Source gas: When melting, the feed tube in a mold release agent.
1. Slow appropriate.
2. Check whether the flow channel turns smoothly, whether decreasing cross-sectional area.
3. Check the airway escape area is large enough, whether there is blocked, the location is on the last place filled.
4. Check whether the spray too much release agent, mold temperature is too low.
5. Use a vacuum.
The reason: because of the pressure suddenly decreases, the molten metal in the sudden expansion of the gas, the impact of the mold, resulting in mold damage.
Do the cross-sectional area of the flow path rapid changes.
The reason: When the metal from the liquid to the solid state solidification space occupied by smaller, without metal supplement will form craters. Typically occurs at slow solidification.
1. Increase the pressure.
2. Changing the mold temperature. Localized cooling, spray release agent, reduce mold temperature. Sometimes just changing the shrinkage position, rather than eliminate shrinkage.
Reason: 1. Filling model is bad, causing molten metal overlap.
2. Mold deformation, resulting molten metal overlap.
3. Mixed oxide layer.
1. Early switched to high speed.
2. Shorten the filling time.
3. Change the fill pattern, gate location, gate speed.
4. Check mold strength is adequate.
5. Check the pin mold assembly is good.
6. Check whether the inclusion oxide layer.
Reason: The first layer on the surface of molten metal cooling molten metal flows through the second layer to the first layer could not melt, but there is sufficient convergence, resulting in different organizations.
1. Improve the filling mode.
2. Shorten the filling time.
8). Bad hole flow generated:
Cause: The molten metal flow is too slow, or too cold, or poor filling model, therefore solidifying metal junction in a hole.
1. With improved cold profiling methods.
2. Check the temperature of the molten metal is stable.
3. Check the temperature of the mold filling is stable.