Common Problems In Die Casting Die

- Sep 06, 2018-

1) Cold Stripe:

Cause: the temperature of the front end of the melt soup is too low and overlaps with traces.

Improvement methods:

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

2. Check whether the shape is not easy to fill; too far away from the closed area (such as fin, protrusion), the blocked area, too small fillet, and pay attention to whether there are ribs or cold spots.

3. shorten the filling time and shorten the filling time.

4. change filling pattern.

5. ways to improve mold temperature:

6. increase melting temperature.

7. check the composition of the alloy.

8. increasing the escape airway may be useful.

9. vacuum devices may be useful.



1. shrinkage stress.

The force is split when the 2. top or the entire edge.

Ways of improvement:

1. increase the fillet.

2. check whether there are hot spots.

3. pressurization time change (cold chamber machine).

4. increase or shorten the closing time.

5. increase the draft angle.

6. increase the ejection pin.

7. check whether there is dislocation or deformation in the mold.

8. check the composition of the alloy.

3) stomata:


1. the air is mixed in the soup.

2. source of gas: melting time, material in tube, mold, release agent.

Improvement methods:

1. slow and proper.

2. check whether the turning of the runner is smooth and whether the cross section area is decreasing.

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

4. check whether the release agent is too much and the mold temperature is too low.

5. use vacuum.

4) cavitation erosion:

Cause: Because the pressure suddenly decreases, the gas in the soup suddenly expands, impacting the mold, causing mold damage.

Improvement methods:

The section area of the runner should not be changed rapidly.

5) shrinkage cavity:

Cause: When a metal solidifies from a liquid to a solid, the space occupied becomes smaller, and shrinkage occurs when no metal is added. It usually occurs at a slower solidification point.

Improvement methods:

1. increase pressure.

2. Change the mold temperature. Local cooling, spraying agent, reducing mold temperature, sometimes just change the position of shrinkage hole, not shrinkage hole.

6) peeling:

Reasons: 1. filling mode is bad, resulting in overlapping of molten soup.

2. die deformation, resulting in overlapping of molten soup.

3. mixed oxide layer.

Improvement methods:

1. switch to high speed early.

2. shorten the filling time.

3. change filling mode, gate location and gate speed.

4. check whether the die strength is enough.

5. check whether the pin device is good.

6. check whether inclusion of oxide layer.


Reason: The first layer of melt soup rapidly cooled on the surface, the second layer of melt soup flow through the first layer failed to melt, but there is enough fusion, resulting in different structures.

Improvement methods:

1. improve filling mode.

2. shorten the filling time.

8). Holes generated by poor flow:

Cause: The soup flows too slowly, or too cold, or the filling pattern is poor, so there are holes in the solidified metal joint.

Improvement methods:

1. same way to improve cold grain.

2. check whether the temperature of molten soup is stable.

3. check whether the mold temperature is stable.

9). Holes in parting surface:

Cause: it may be a shrinkage cavity or a blowhole.

Improvement methods:

1. if the shrinkage hole is reduced, the gate thickness or the inlet thickness of the overflow well will be reduced.

2. cooling gate.

3. if stoma, pay attention to exhaust or curling.


Reason: 1. the clamping force is insufficient.

2. mold malfunction.

3. mold strength is insufficient.

4. the melting temperature is too high.


Cause: shrinkage occurs below the surface of the compression parts.

Improvement methods:

1. methods for improving shrinkage cavity.

2. partial cooling.

3. heat the other side.

12) carbon deposition:

Cause: release agent or other impurities are attached to the mold.

Improvement methods:

1. reduce the spray amount of release agent.

2. raise the mold temperature.

3. choose suitable release agents.

4. use soft water to dilute release agent.

13) bubbling:

Cause: the gas roll is underneath the surface of the casting.

Ways of improvement:

1. reduce the volume of gas (same air hole).

2. cooling or preventing low mold temperature.



1. zinc deposits are attached to the mold surface.

2. melt the soup to impact the mold, causing damage to the die surface.

Improvement methods:

1. reduce mold temperature.

2. reduce the surface roughness.

3. increase the draft angle.

4. coating.

5. change filling pattern.

6. reduce gate speed

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