In die-casting and casting production, in order to improve the service life of mold die-casting spray guns, cavities, and punches, and to ensure smooth demolding of die-casting parts, and to ensure a smooth surface and complete and clear contour of die-casting parts, some auxiliary materials such as release agents and punch lubricants need to be used.
1、 The function of die-casting release agent:
1. Has good lubrication performance at high temperatures;
2. Cooling the mold by adjusting the temperature of each part of the mold to achieve relative stability, which is beneficial for improving the quality of castings and production efficiency;
3. Avoiding direct impact of molten metal on the mold and improving its working conditions;
4. Prevent mold sticking;
5. Reduce friction between castings and mold forming parts (especially cores), as well as wear on cores and cavities, prolong mold life, and improve surface quality of castings.
2、 Requirements for Die Casting Release Agent:
1. Low volatility point, at 100-150 ℃, the diluent can quickly evaporate without increasing the gas inside the mold cavity;
2. Good coating properties, no accumulation, able to form a thin film layer at high temperatures, and easy to clean;
3. No corrosive effect on molds and castings;
4. Minimize environmental pollution, that is, odorless, does not release or decompose harmful gases;
5. Stable performance, not easily volatile in air, does not precipitate or decompose during the shelf life;
6. Simple preparation process;
7. Rich sources and low prices.
Water based release agents should generally be preferred for die-casting release agents because they have the characteristics of low cost, easy volatility, and can not only play a role in demolding, but also regulate the mold temperature during demolding, and are easy to prepare.
When using release agents, whether by spraying or brushing, they should not be too thick and the thickness should not be uniform. The mold can only be closed and die cast after the diluent evaporates, thus avoiding the increase of gas volume in the mold cavity or pressure chamber and the possibility of gas holes in the casting, and avoiding the formation of high back pressure due to the increase of gas, which makes forming difficult. During use, the exhaust system should be cleaned at all times to avoid the exhaust system losing its function due to blockage by release agent. At the same time, it is necessary to avoid turning points and accumulation of release agent at convex corners to prevent unclear contour of the die-casting.
