In the production process of aluminum alloy die casting, temperature is one of the core process elements. The temperature control of the die casting mold directly affects the quality and production efficiency of the product. The choice of the temperature control method of the die casting mold is particularly important. Based on the actual situation and the actual situation of aluminum alloy die-casting, this article analyzes the temperature control method of aluminum alloy die-casting mold to achieve mold thermal balance and solve the problem of hot joint.
With the vigorous development of the automotive industry, it has brought more opportunities and new challenges to the die casting industry. In die-casting production, mold temperature has an important influence on casting quality, mold life and production cycle. Therefore, in modern die-casting technology, mold temperature control is an indispensable process. This article focuses on the importance of die-casting mold temperature , Principles, control methods are explained, and a set of die casting mold temperature control methods selected for the control method are briefly analyzed.
2. The importance and control principle of die casting mold temperature
(1) The importance of die casting mold temperature
The die-casting mold is the molding process equipment in the casting production process. Whether the temperature field distribution established in the mold is stable has an important impact on the quality of the casting, the production efficiency and the service life of the mold. It directly affects the cost and economic benefit of the casting production. The temperature field in the mold must be within the scope of the process requirements, so as to obtain castings with qualified appearance and internal quality. Conversely, if the temperature is too high, defects such as strains and bubbles will be formed, which will extend the cooling time and reduce the production efficiency. Defects such as cold insulation, insufficient pouring, and air holes are generated. Die-casting molds are produced under high-temperature and high-pressure environments for a long time. If the temperature field of the mold is unstable, and the long-term periodic thermal expansion and contraction, the mold is more likely to fail, which greatly shortens the service life and reduces the production efficiency.
(2) Principle of temperature control of die casting mold
During the casting process, the heat exchange between the mold and the molten metal reaches the ideal heat balance, that is, the mold absorbs heat and discharges heat to achieve dynamic thermal balance. After the process is selected, the mold temperature reaches the range of the casting’s working temperature, which is easy to form a heat joint. Local cooling is carried out to promote the formation of heat balance.
3. Hot section
(1) Production location: The temperature of the casting structure is the highest during the die casting process, and it is easy to form shrinkage cavities, shrinkage and stress concentration during the cooling process.
(2) Control mode-point cooler
In order to achieve the purpose of saving water, the point cooler adopts the method of water recycling, and in order to ensure the sufficient pressure, a collection box is added.
(3) The core at the hot joint of the casting increases high-pressure spot cooling.
(4) Spot cold water treatment: Spot cold water will encounter sudden cooling and heat in the cooling pipeline, and the pipeline is small. The old water treatment generally uses softening treatment, which often fails to meet the water quality requirements in production. Blockages occur frequently, causing huge human, material, and financial losses. Generally, RO reverse osmosis water treatment devices are used to treat cold water into pure water.
4. Heat balance
(1) Principle: During the die-casting production process, the heat absorbed by the mold and the heat discharged must be consistent, so as to avoid the mold getting colder or hotter, and reducing shrinkage, shrinkage, and shrinkage caused by uneven temperature of the mold. Porosity and other casting defects. Improve the appearance and internal quality of castings, the service life of molds and production efficiency. Reaching thermal equilibrium is the process of cooling the mold at a high temperature and heating it at a low temperature.
(2) Control mode—die casting mold temperature machine
The mold temperature machine is divided into water type and oil type. The control temperature is about 160 ℃ and the environmental requirements are generally selected. The water type is generally selected, and the oil type is generally selected above 160 ℃. The main function of the mold temperature machine is to cool the mold parts, and the temperature adjustment and control in the production process of die casting are not enough.
(3) Control mode-mold cooling unit
The mold cooling unit is used in conjunction with the mold’s own cooling circulating water to cool the parts with high mold temperature to maintain the thermal balance of the mold cavity temperature.
5. Temperature monitoring method of die casting mold
(1) Handheld thermal imager
Conduct thermal imaging test for each shift, and adjust the mold according to the temperature
(2) Temperature monitoring system of thermocouple or thermal imager.
According to the situation of the mold, embed a thermocouple in the mold (or place a thermal imager above and to the left and right of the mold), monitor the temperature distribution of the mold in real time through the control system, and adjust the temperature of the mold to realize the mold temperature by analyzing the monitoring data Temperature monitoring.