In the process of aluminum alloy die-casting production, temperature is one of central technological factors. Temperature control of die casting mold directly affects quality of product and production power. Selection of temperature control method of die casting mold is particularly important. Based on actual situation, combined with actual situation of aluminum alloy die-casting, this paper analyzes temperature control method of aluminum alloy die-casting mold to complete heat balance of mold and deal with hot section.

With vigorous development of automobile profession, it has brought more opportunities to die-casting profession and brought new challenges. In die-casting production, mold temperature has an important influence on casting quality, die life and production cycle. Therefore, in modern die-casting technology, mold temperature control is an indispensable technical method. This paper clarifies importance, principle and control method of die-casting mold temperature, analyzes temperature control method of a set of die-casting molds selected for control method.

 

Die casting mold is molding process equipment in casting production process. Whether temperature field spread in mold is stable or not has an important influence on casting quality, production power and die life, which is directly related to cost and economic benefit of casting production. Temperature field in mold should be within scale of process requirements, so that castings with acceptable appearance and internal quality can be obtained. On the contrary, if temperature is too high, it will constitute shortcomings such as strains and bubbles, which will prolong cooling time and reduce production power. If temperature is too low, there will be disadvantages such as cold separation, insufficient pouring, and pores. Die casting mold is produced under high temperature and high pressure for a long time. If temperature field of mold is not stable, cyclical thermal expansion and contraction for a long time, mold is more simple and fails, which greatly shortens service life and reduces production power.

During casting process, heat exchange between mold and molten metal reaches ideal heat balance, that is, mold absorbs heat and discharges heat flat, reaches dynamic heat balance. After process is selected, mold temperature reaches scale of working temperature of casting, local cooling of simple hot section is performed to promote composition of heat balance.

(1) Occurrence part: Casting structure has the highest temperature during die casting process, and it is easy to form shrinkage holes, shrinkage, and stress accumulation during cooling process.
(2) Control method - point cooler
In order to achieve purpose of water saving, point chiller adopts method of water circulation, and in order to ensure sufficient pressure, a header box is added.
(3) Core of hot section of casting is added with high pressure.
(4) Point cold water treatment: point cold water will encounter sudden cooling and heat in cooling pipeline, and pipeline is fine. Old water treatment generally uses softening treatment, which often fails to meet water quality requirements during production. Blocking frequently occurs, causing 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.

During die-casting production process, heat absorbed by mold and heat discharged should be consistent, so as to prevent mold from getting colder or hotter, reduce defects such as shrinkage and porosity caused by uneven mold temperature. Improve appearance and internal quality of casting, life of mold and production power. Arriving at heat balance is a process of cooling local temperature of mold and heating it at a low temperature.

Mold temperature machine is divided into water type and oil type. Control temperature is about 160℃. For general selection of water-type mold temperature machines with high environmental requirements, oil-type mold temperature machine is generally selected above 160℃. Main function of mold temperature machine is to use cold mold parts, temperature adjustment and control during die-casting production process are not good.

Mold cooling unit is used in conjunction with mold's own cooling circulating water to cool part with high mold temperature to maintain heat balance of mold cavity temperature.

Thermal imaging test for each shift, conditioning of mold according to temperature conditions

According to condition of mold, thermocouple is buried in mold or placed on the top, left and right sides of mold, and temperature distribution of mold is monitored in real time through control system. After analysis of monitoring data, mold temperature is adjusted to complete temperature monitoring of mold.

Mold temperature is one of the most important process parameters. It not only determines quality of casting, but also seriously affects service life and production power of mold. Therefore, to ensure that parameters are controllable, try to use an automatic temperature control system. Temperature control of die casting mold is a combination of various methods. It can not be considered that temperature of mold can be controlled by only one temperature control method. Different temperature control methods are adopted for different conditions of die-casting production process and die casting mold. With development of die-casting technology, new temperature control method is also constantly updated. Application of new method will definitely further improve level of mold temperature control, contribute to production of faster and better die-casting parts.