In order to improve the service life of the die, heat treatment technology should be taken as the starting point.
1. Mould surface cleaning
First, only crude oil or abrasive belt is used, and then heat treatment is carried out. When you come back, polish with fine kerosene.
First, grinding the fiber wheel can effectively remove and polish the black skin. Or sandblasting test with 800 mesh boron carbide should remove the black skin without too much effort to re-grind.
2. The Difference between Processing and Unprocessed
Recognition by tapping sound. The metallographic structure and internal friction of castings are different from those of quenched and tempered castings. A tap can be distinguished.
3. Soft spot prevention
The scales and rust spots should be removed before heat treatment. During quenching and heating, the die surface should be properly protected. Vacuum electric furnace, salt bath furnace and protective atmosphere furnace should be adopted as far as possible.
When cooling the die after quenching and heating, the appropriate cooling medium should be selected, and the long-term used cooling medium should be filtered or replaced regularly.
The basic principle of die casting die design, cavity layout considers 1. Balance the layout as much as possible. 2. In order to prevent overflow caused by unbalanced load of die casting die, the layout of die cavity and the opening of gate should be symmetrical. Three. Cave layout is as compact as possible to reduce die size. Consider flow direction 1. It can smoothly guide liquid zinc to fill the die cavity without eddy current and smooth exhaust. 2. Avoid the front impact of zinc liquid on the core with smaller diameter, and prevent the core from moving (core displacement) or deformation.
Consider heat loss and pressure drop of 1. The smaller the heat loss and pressure drop, the better. 2. This process should be very short. Three. The cross-sectional area of the runner should be large enough. 4. Avoid bending and sudden change of direction (change direction with arc angle). 5. The surface roughness of the runner is low. 6. Multi-point pouring can reduce pressure drop and injection pressure, but there will be mold closure problems. Consider flow balance 1. When filling with multi-cavity, the runner should be balanced so that the plastic can be filled at the same time to ensure the consistency of the quality of the mould. 2. Use natural balance arrangement as far as possible. Three. When the natural balance cannot be achieved, the artificial balance method is used to balance the runner. Considering that the rubbish can be filled smoothly without affecting the flow and pressure loss, the runner volume (length or cross-sectional area) can be reduced, thus reducing the cost of garbage generation and recycling.
Maintenance technicians should know zinc alloy die casting, but in the first die casting work, this knowledge may not be perfect, so many times there will be unknown, please note that die casting as follows.
In many automobile, motor, electronics and other industries, this kind of die-casting is very many, and the work of die-casting also needs attention. First of all, we need to consider its demoulding problem, because once the demoulding process occurs, it is very unsafe, but also a need to pay special attention to the problem. Secondly, the thickness of the inner wall of the die casting must be carefully considered. If the thickness is too thick and the void is too large, it will have a certain impact on the filling work.
The structure of the die should also be taken into account to avoid the complex structure of the die. Once the structure is particularly complex, multi-core-pulling method should be considered for regulation. In some die castings, the appearance of the injector may be required, which is very important. Finally, it should be noted that the design and placement of the die can not imitate the core pulling below, preferably on both sides.