In the production process of aluminum alloy die-casting, temperature is one of the core process elements. The quality of die-casting mold temperature control directly affects product quality and production efficiency. The choice of die-casting mold temperature control method is particularly important. Based on the actual situation, this paper analyzes the temperature control method of aluminum alloy die-casting mold in combination with the actual situation of aluminum alloy die-casting, so as to realize the thermal balance of the mold and solve the problem of thermal joints.

1 Introduction

With the vigorous development of the automobile 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 has become an indispensable process method. This article discusses the importance of die-casting mold temperature. , principles and 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

Die-casting mold is the molding process equipment in the casting production process. Whether the temperature field distribution established in the mold is stable or not has an important impact on the casting quality, production efficiency and mold service life, and is directly related to the cost and economic benefits of casting production. The temperature field in the mold must be within the range of process requirements, so that castings with qualified appearance and internal quality can be obtained. On the contrary, if the temperature is too high, defects such as strains and bubbles will be formed, which will prolong the cooling time and reduce the production efficiency; Defects such as cold isolation, insufficient pouring, and pores are generated. Die-casting molds are produced in a high temperature and high pressure environment for a long time. If coupled with the unstable temperature field of the mold 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 an ideal thermal balance, that is, the mold absorbs and discharges the same amount of heat to achieve a dynamic thermal balance. Spot cooling is carried out in place to promote the formation of thermal balance.

3. Hot Festival

(1) Generation part: The casting structure has the highest temperature during the die-casting process, and it is easy to form shrinkage cavities, shrinkage porosity and stress concentrations during the cooling process.

(2) Control method - spot cooler

In order to achieve the purpose of water saving, the spot cooler adopts the method of water circulation, and in order to ensure sufficient pressure, a collecting and distribution box is added.

(3) High-pressure spot cooling is added to the core at the hot joint of the casting.

(4) Cold water treatment: In the cooling pipeline, the cold water will encounter sudden cooling and heat, the pipeline is small, etc. The old water treatment generally uses softening treatment, which often fails to meet the water quality requirements in production. Blockage occurs frequently, resulting in huge loss of manpower, material resources and financial resources. Generally, RO reverse osmosis water treatment device is used to treat cold water into pure water.

4. Thermal balance

(1) Principle: In the process of die casting production, the heat absorbed by the mold and the heat emitted should be consistent, so as to avoid the mold becoming colder or hotter, and reduce shrinkage cavities, shrinkage porosity, and shrinkage caused by uneven mold temperature. Casting defects such as pores. Improve the appearance and internal quality of castings, mold life and production efficiency. Achieving thermal equilibrium is the process of cooling the mold where the temperature is high, and heating up the low temperature.

(2) Control method - die-casting mold temperature machine

The mold temperature machine is divided into water type and oil type. The control temperature is around 160 °C and the water type is generally selected for those with higher environmental requirements, and the oil type is generally selected for higher than 160 °C. The main function of the mold temperature machine is to cool the mold parts, and the temperature adjustment and control in the die casting production process are not enough.

(3) Control method - mold cooling unit

The mold cooling unit is used in conjunction with the cooling circulating water of the mold to cool the high temperature part of the mold to maintain the thermal balance of the mold cavity temperature.

5. Die-casting mold temperature monitoring method

(1) Handheld thermal imager

Thermal imaging test is carried out for each shift, and mold adjustment is carried out according to temperature conditions

(2) Thermocouple or thermal imager temperature monitoring system.

According to the situation of the mold, embed thermocouples in the mold (or place thermal imagers above the mold and on the left and right sides), monitor the temperature distribution of the mold in real time through the control system, and adjust the mold temperature by analyzing the monitoring data to realize the mold temperature. Temperature monitoring.