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What cooling and temperature control techniques are available for aluminum die casting molds?

Published on:

2023-03-20

What cooling and temperature control techniques are available for aluminum die casting dies? During the continuous production of die casting dies, in most cases, it is necessary to manually enhance the cooling by cooling the die head with water or by using heat transfer oil (heat transfer oil) to control the temperature of the die head.
1. Depending on the structure of the casting, different temperatures in different parts of the die are controlled by several independent cooling water circulation systems, thus providing conditions for sequential solidification of the casting; it is also possible to select the most sensitive and suitable location in each cooling circuit of the die, install thermal sensors to scan and monitor the temperature, and then operate the opening and closing of the electric valves in the input section by means of adjustable controllers, although this method is good Although this method is good, the investment is high, especially the cost of the thermal sensor and its circuitry, and it is usually only used to produce die castings with larger dimensions and higher requirements.
2, through the automatic heating and cooling device of heat transfer oil, die casting special mold temperature machine, to control the mold temperature. Compared with simply cooling the mold, it is much better to control the moving and fixed mold within a certain temperature range. The die casting mold temperature machine uses heat transfer oil as the medium which is the working fluid leading to the mold. The microcomputer PID regulates and controls the oil temperature through the heating and cooling efficiency of the heat transfer oil and the circulation rate.
The cooling water temperature of the die casting mold cannot be too high, otherwise the steam pressure formed when the water boils will affect the cooling effect. The upper limit of cooling water temperature is 95℃ and the lower limit is 10℃. The water cooling hose connected to the die should not be broken, and the cooling water should be softened by ion exchange method, otherwise the water will gradually produce scale on the inner wall of the cooling channel, and the white precipitate will make the cooling effect worse.
Due to the high temperature of die-casting core surrounded by alloy liquid, it is easy to form a sticky mold in production, and due to the rapid increase in temperature, the local hardness of the core decreases, which leads to dimensional deviation casting core temperature is too high is easy to cause porosity and shrinkage; high temperature of the movable model core and slider will shorten the life of the slider and guide channel.
In order to avoid the above defects, for small diameter cores, foreign countries have developed a mold core jet cooler with fine hole cooling. Even if the mold core temperature is 200°C, a special piston pump is used to maintain the drainage capacity at a pressure of 1 MPa or more, injecting a large amount of cooling water and stopping the drainage immediately. The high pressure air flow can be filled into the cooling circuit to drain the residual cooling water. This device not only improves the life of the core, but also improves the quality of the die casting.
Temperature control of die casting mold is one of the important parameters in the die casting process, which directly affects the quality and economic efficiency of die casting. Fully understand the role of die-casting temperature control and various factors affecting die-casting temperature, and bring the application of die-casting heat balance calculation into production, is an essential condition to achieve the scientific level of die-casting production.