Epoxy resin pouring is a production process with strong technology and high technical difficulty. In order to ensure the quality of the transformer, each operator must operate in strict accordance with the provisions of this operation instruction. Because the appearance quality of epoxy casting products is affected by many factors, it is very difficult to quantify and determine the cause of the problem accurately, so the appearance quality control of casting parts becomes a difficulty in the casting technology.
Vacuum pouring is the most widely used and mature technology in epoxy resin pouring. For an electrical insulation product poured with epoxy resin, it requires perfect appearance, stable size, qualified mechanical and electrical properties. These properties depend on the design of the parts, the quality of the mould, the selection of the casting materials, the control of the casting process conditions and so on. The key point of vacuum casting of epoxy resin is to reduce the air gap and air bubble in casting products as much as possible. In order to achieve this goal, it is necessary to control the vacuum degree, temperature and process time in each process of raw material pretreatment, mixing and pouring.
Technology and principle of vacuum system for epoxy resin pouring
Epoxy resin pouring is a process of pouring epoxy resin, curing agent and other materials into a set mold, and curing them into thermosetting products by crosslinking with thermoplastic fluid. Because epoxy resin casting products have excellent electrical and mechanical properties, it has been widely used and developed in the electrical industry.
Epoxy resin pouring is equipped with up to 8 vacuum joints, which can be connected with vacuum pipes in one or more molds. The mold obtains vacuum through these joints. Each joint has an independent vacuum control valve, so as to separately regulate the vacuum degree at each point of the mold. The vacuum tank ensures a continuous, stable and sufficient vacuumizing process, even for large moulds. By using a vacuum tank, a relatively small vacuum system can be selected. This ensures that the vacuum system provides the most economical solution in the case of maximum air extraction. At the same time, the vacuum system is compact and movable, which can be flexibly used anywhere.
Compared with traditional insulating materials, vacuum system technology for epoxy vacuum casting products has many unique advantages:
1. No air gap or little air gap, excellent electrical insulation performance of products;
2. Good fluidity of casting, natural filling cavity, good uniformity of products;
3. Due to the good electrical performance, the product can be miniaturized and the host structure optimized;
4. The product can be made into complex shape, and one-time forming, with good integrity of metal inserts and insulation materials;
5. Good weather resistance, can be applied to indoor and outdoor fields;
6. The product is solid, flame-retardant, safe and convenient to use.
Through the analysis of the application of vacuum system in epoxy resin pouring, we can know that the development of epoxy resin pouring from atmospheric pressure molding to vacuum molding. Vacuum casting makes the bubbles in the castable easier to be discharged, the internal quality and appearance quality of the products are greatly improved, thus promoting the development of power transmission and transformation technology.