Here are some common problems and solutions in die casting

1. Hammer head jamming

To avoid hammer head jamming, you can start from two aspects: 1. In production, measure the temperature frequently to avoid the hammer head and the cylinder temperature being too high, causing the hammer head to jam; 2. Use high-quality alloy materials to avoid impurities from infiltrating. When putting the material back, also be careful not to let impurities mix in, so as to avoid impurities sticking to the hammer head and causing it to jam.

2. Injection head stuck in the goose neck

 When encountering the problem of hammer head jamming, wait until the equipment is at normal temperature, and try to rotate the hammer head. If it cannot be rotated, then use the method of replacing the cylinder to solve the problem and remove the hammer head. If you want to solve the jamming problem quickly, the fastest way is to change the material pot.

3. When the die casting machine is feeding, it often happens that dozens of molds cannot be cast, and the material can only be cast after waiting for a few minutes

Generally, when encountering this kind of situation, it should be that the nozzle head or the nozzle body is blocked. At this time, observe whether there is no bright spot at the top of the material head, if all are gray in cross-section, it means that the nozzle is blocked. The solution is as follows: 1. Increase the temperature of the nozzle appropriately; 2. Reduce the time of leaving the nozzle by 0.1 to 0.2 seconds; 3. Slightly reduce the cooling water of the fixed mold.

4. Thin-walled products are prone to cracking during aluminum die casting

 You can analyze it from the following points:

1> There may be problems with the material. The use of die-casting materials should try to control the proportion of waste materials not to exceed 30%:

2> The mold opening is not good. One is that the ejection force is unbalanced; the other is that the cooling water is not reasonably opened, resulting in uneven mold temperature; the third is that the filling flow is unreasonable.

3> Improper selection of process parameters. The problem of process parameters is mainly wrong in the retention time and ejection delay time. The retention time should not be too long, about 3 seconds per mm wall thickness; the ejection delay time should not be too long, generally 0.5-2s.

5. When processing ADC14 material by die casting, the feedback material is too hard and the cutting tool is easy to wear

To solve this problem, you can look at it from the following points:

1> The most critical thing is that there should be no impurities in the composition of the material, that is to say, the hard point, it is best to use all new original materials for the ratio, and not to use recycled materials. Especially the quality of the S1 element should be good;

2> Special gem blades produced for these harder alloys should be used, and the service life is generally about 7 days.

6. Why do some aluminum die-castings have black spots when polished?

There are several reasons: it may be silicon oxide or alumina ingots to solve the problem. But the biggest possibility comes from the release agent. If too much release agent is sprayed or the organic matter content of the release agent is too high, these organic matter will be reduced to carbon elements at the temperature of hot-dissolving aluminum, and some will become organic macromolecular polymers. Carbon molecules and polymers are mixed and included in the surface layer during aluminum casting, becoming the black spots we see. Therefore, reduce the concentration of the spray, use other sprays; or extend the blowing time after spraying.

7. In the die casting process, sometimes there is metal overflow: Why does metal overflow occur sometimes?

The reason may be that the dynamic and fixed molds are not tightly sealed, and the gap between the two is relatively large; or the locking force is insufficient, causing metal overflow; or the dynamic and fixed molds of the die casting machine are installed in parallel; or the span of the support plate is large, and the injection force causes the bushing to deform and produce spray. If the above reasons are encountered, the overflow situation can be solved by the following debugging: reinstall the mold; increase the locking force: adjust the die casting machine to keep the dynamic and fixed mold mounting plates parallel to each other; add a support plate on the dynamic mold to increase the stiffness of the bushing.

8. Why can’t the hole processing of aluminum die-casting exceed 0.25mm?

In order to be suitable for die casting, people have added a lot of silicon to the aluminum alloy used for die casting. When the aluminum alloy condenses in the mold, these silicon will float to the surface to form a layer of silicon film that is very hard and wear-resistant. Some OEM designers use this feature to design the inner surface of the die-casting hole directly as a bearing surface. This silicon surface layer generally has a thickness of only 0.2 to 0.9mm. If too much processing is done, the life of this bearing surface will be shortened.

9. What are the reasons for the pattern after anodizing of die-casting parts?

1> Currently, the main reason is that the spray and injection oil are not evenly distributed, and they gather locally, causing abnormal composition of the surface aluminum alloy or cold isolation spots, resulting in the phenomenon of pattern after oxidation; the pattern of oxidation is basically consistent with the pattern on the die-casting part.

2> Due to improper high-speed switching position, under-casting occurs, and there will be patterns after oxidation.

3> The textbook says that the high copper ion content in the oxidation tank is also a cause of patterns, but this situation is rare.

10. What should I do if the die-casting mold sticks?

1> First check whether the mold temperature is normal, reduce the pouring temperature of the alloy and the mold temperature;

2> Check whether the release agent ratio is abnormal, try to replace the release agent, and polish the surface of the spray position for debugging. For molds that have been nitrided, be careful not to polish too much to prevent damage to the nitrided layer on the surface and cause the mold to become more sticky;

3> Improve the design structure of the pouring system to avoid the continuous flushing of the alloy liquid on the cavity wall or core;

4> Modify the mold cooling system;

5> Adjust the die-casting process parameters, appropriately reduce the injection speed, and shorten the second speed stroke.