As we all know, the working conditions of die-casting molds are bad, and there are many factors affecting the life of the mold. Let's discuss the factors affecting the life of the mold and its control.

1. Formulate a reasonable processing technology

After the mold design is completed, the relevant technical documents are generally issued directly to the production department, and the process adopted by Shengji Company based on years of accumulated experience is first input into the process group, and professional technicians formulate reasonable technical documents according to specific requirements. Enter the production department and quality department;

2. Formulate reasonable matching clearance and strict control of the pipe for precision

Unreasonable matching gap between the movable structures of the mold will directly lead to the failure of the mechanism of the mold, causing mechanical failure, damage to the mold and life; the gap input technical pattern calculated by the designer and the technician according to the specific project, the production department strictly according to the diagram Construction, quality department is responsible for the acceptance and determination of the implementation results; in addition, it is necessary to pay attention to some of the high-quality areas to put on the appropriate penetration gap, otherwise the mold expansion will cause the thermal expansion and extrusion will lead to deformation, cracking, product strain, Pull crack, profile flash.

3, using high-speed NC processing technology to reduce EDM EDM technology has been an important means of mold processing for many years, but we know that EDM is the use of electrodes and workpieces in a certain working medium to generate pulse discharge, in the spark Immediately after high temperature and high pressure, the workpiece material is melted and vaporized. After the electrical discharge process, a processing metamorphic layer---"white layer" will be formed on the surface of the mold, which will lead to premature crack failure in the die casting production; therefore, try to adopt High-speed NC machining instead of pulse discharge machining will help improve the life of the mold. At the same time, high-speed NC machining can ensure high dimensional accuracy, good surface roughness, reduced polishing man-hours, and even no need for polishing. In addition, the surface of the mold after NC machining is in a compressive stress state, which helps to delay the occurrence of early cracks on the surface of the mold.

When pulse discharge machining is not avoided, it is recommended to use multiple discharge machining. In the final stage, low current and high frequency discharge are used, and then the "white layer" is polished.

4, reduce residual stress

The cavity parts will generate residual internal stress during each processing step, which will make the parts unstable and easy to deform or even crack during operation. Therefore, corresponding measures must be taken to control:

a. Ensure reasonable structural design; firstly, ensure that the parts have sufficient rigidity and uniform wall thickness, and “smooth transition” should be handled for the stepped or corner areas.

b. Arrange the processing technology reasonably; the roughing and finishing are carried out in stages, and one or more semi-finishing operations are added to the special parts to ensure the natural failure time of the parts.

c. After the processing is completed, the parts are subjected to stress relief treatment;

5, strict control of the cooling system

In the die-casting production, the mold is repeatedly impacted by high temperature, high pressure and high speed metal liquid, and its life impact is most significant. When the internal cooling system cannot work normally, the die casting site can only be operated by spraying external cooling, which will make the mold chill. Heat, seriously affecting normal life;

Therefore, the production process should pay attention to the following:

a. Strictly follow the design drawings to ensure the cooling channel flow;

b. The depth of the point cooling ensures that the processing is in place, and the length of the nozzle is strictly processed according to the design drawing and confirmed by inspection;

c. Each cooling channel has a corresponding number to ensure easy adjustment and control of the heat balance of the mold during die casting production;

6. Mold material and heat treatment process

The advantages and disadvantages of the cavity material have direct factors on the life of the mold. High-quality mold steel needs to have high toughness and ductility, thereby improving the thermal fatigue resistance of the steel and improving the service life of the mold.

In the heat treatment process, the heat treatment process should be strictly controlled. Parts of different geometrical dimensions should be divided into furnaces and differentiated processes; for castings with special surface requirements, consider appropriate mold surface coating treatment techniques;