In aluminum alloy die-casting production, mucosal strain has always been a problem that troubles us. When mucous membrane occurs, the scrap rate of the product will be greatly increased, which will increase the amount of raw materials. In addition, mold repair and debugging will also take time. , will greatly affect the output, thus affecting the customer’s delivery time. Therefore, we should strictly control the mold at the beginning to improve the yield rate. If there is a problem, analyze the cause immediately and make improvements. The following are the reasons why the mold will stick.

1. Less dosage for stripping

Let’s first look at what demoulding is. Demolding means removing the pressed product from the mold after the die-casting is completed. Before demoulding, a layer of release agent is sprayed on the surface of the mold through automatic spraying equipment, robots or manual spray guns. This forms a dense film on the surface of the mold, provides a layer of lubricating medium on the mold, and isolates the mold from direct contact with the high-temperature aluminum liquid, which not only facilitates the molding of the workpiece, but also extends the service life of the mold. Therefore, it is very important whether there is a dense film on the mold. If the amount of die-casting release agent sprayed per unit area is small and a piece is missing here, it will easily lead to the impact of aluminum liquid on the mold in the area that lacks the protection of the release agent. Direct washing will easily cause mucous membrane. At the same time, we also know that the release agent has an oil-in-water structure. When the release agent contacts the high-temperature mold, the water evaporates quickly. The vaporization takes away part of the heat and has a cooling effect on the mold, so there is a lack of release agent. This piece of protection can also easily lead to carbon deposits. Therefore, the dilution ratio of the die-casting release agent is too high (far beyond the recommended range of the die-casting release agent), the spraying time is short, the spraying amount is small, the lubrication and adhesion of the release agent are not good, etc. are all die-casting problems that are sprayed on a single unit area. The reason for the small release dose, for example, 20% solid content, is usually recommended to be diluted 100-150 times. As a result, under the same situation, the customer diluted more than 300 times, which can easily cause mucous membranes.

2. Check whether the draft angle of the casting is maximized. Increasing the draft angle can reduce mold sticking.

3. Check whether the mold is rough or there are areas with reverse draft, and repair and polish these areas.

4. If the casting always sticks to the fixed mold, you can deliberately roughen the unimportant parts of the movable mold to increase the tightness of the movable mold so that the casting will no longer stick to the fixed mold.

5. Check whether the surface of the front mold has cracked or sticky material

6. The material composition of ADC12 requires the Fe content to be less than 1.2%. However, if the Fe content is less than 0.6%, mold sticking is more likely to occur.