1).Cold lines:

 Reasons: the front end of the melt temperature is too low, there are traces when stacked.

Improvement:

1. Check the wall thickness is too thin (or manufacturing), thin areas should be directed to filling.
2. Check whether the shape is not easy filling; too far away, an enclosed area (such as fin (fin), convex), the blocked area, the fillet is too small and so difficult to fill. And note if there are rib point or cold spots.
3. Shorten the filling time. Shorten the filling time: ...
4. Change the fill mode.
5 Improve the methods of the mold temperature: ...
6. Increase the temperature of the melt.
7. Check the alloy composition.
8. Increase escape airway may be useful.
9. Plus vacuum device may be useful.

2). Cracks:
Reasons: 1. Shrinkage stress.

2 Top or the entire edge by split.
Improve the way:
1. Increase the fillet.
2. Check for hot spots.
3. Pressurization time change (cold chamber machine).
4. Increase or shorten the clamping time.
5 Increase the draft angle.
6. Increase the ejection pin.
7. Check whether the mold dislocation, deformation.
8. Check the alloy composition.
3). Stomata:
Reasons: 1. Air inclusions in the melt.
     2 Gas sources: melting, in the barrel, in the mold release agent.
Improvement:
1. Appropriate slow.
2. Check the flow channel turn smooth, cross-sectional area is decreasing.
3. Check escape airway area is large enough, whether it is blocked, the location in the last filling.
4. Check the release agent spray too much, the mold temperature is too low.
5 The use of a vacuum.
4) Cavitation:
Reasons: due to the sudden decrease in pressure, so that a sudden expansion of the gas in the molten, the impact of mold, causing mold damage.
Improvement methods: cross-sectional area of ??the flow channel is not rapidly changing.
5). Shrinkage:
Reason: When the metal by liquid solidification smaller the amount of space in the solid state, in the absence of metal supplement will be the formation of shrinkage. Usually occurs in the slow solidification at.
Improvement:
1. Increase the pressure.
2. Changes in mold temperature. Local cooling, spray release agent to reduce the mold temperature. Sometimes just changing the the shrinkage location, rather than eliminate shrinkage.
6) Peeling:
Reasons: 1. Filling pattern is bad, resulting in overlapping melt.
  2. Mold deformation, resulting in overlapping melt.
      3. The mixed oxide layer.
Improvement:
1. Early switch to high speed.
2. Shorten the filling time.
3. Change the fill mode, gate location, gate speed.
4. Check the mold strength is adequate.
5 Check the pin-mode device is good.
6. Check for mixed oxide layer.
7). Ripple:
Reasons: the first layer of the melt caused by rapid surface cooling, the second layer of the melt flow through the first layer in a failure to melt, but there is enough integration organizations.
Improvement:
1. To improve the filling pattern.
2. Shorten the filling time.
8). The flow of bad holes generated:
Reasons: the melt flow is too slow or too cold, or poor filling pattern, so in the solidification of the metal junction hole.
Improvement:
1. To improve the cold pattern method.
2. Check the melt temperature is stable.
3. Check mold temperature and charge stability.
9) In the parting surface hole:
The reason: It may be shrinkage or pores.
Improvement: 1. Shrinkage, reduce the gate thickness or overflow wells imports thickness.
2. Cooling the gate.
3. If the pores, pay attention to the problem of exhaust or volume gas.
10). Flash:
Reasons: 1. Insufficient clamping force.
   2. Mold clamping bad.
      3. Insufficient mold strength.
   4. The melt temperature is too high.
11). Shrinkage Depression:
Reasons: the shrinkage occurred in the pressure surface below.
Improvement:
1. Improve shrinkage method.
2. Local cooling.
3. Heated on the other side.
12) Coke:
Reason: attached to the mold release agent or other impurities in the product on.
Improvement:
1. Reduce the amount of release agent spraying.
2. Elevated mold temperature.
3. Select the appropriate release agent.
4. Use soft water diluted release agent.
13). Bubble: the following reasons: gas volume in the casting surface.
Improve the way:
1. Reduce the volume gas (vent).
2. Cooling or anti-low mold temperature.
14). Stick mode:
Reasons: 1. Zinc plot attached to the mold surface.
2. Melt the impact of the mold, resulting in damage to the mold surface.
Improvement:
1. Reduce mold temperature.
2. Reduce the designated surface roughness.
3. Increased draft angle.
4. Coating.
5 Change the fill mode.
6. Reduce the gate speed