In the application of die casting industry, the role of die casting mold temperature machines is very important, especially in the manufacturing of magnesium alloys, aluminum alloys, and zinc alloys. Uneven or inappropriate mold temperatures can lead to dimensional instability of castings, generating thermal pressure during the production process, and ejecting defects such as casting deformation, surface depressions, mold adhesion, internal shrinkage, and hot bubbles. It also has an impact on the production cycle, such as unstable variables in filling time, cooling time, and spraying time. The life of the mold can also be impacted by supercooling and overheating, resulting in thermal cracking of expensive steel, accelerating its aging.
What is the function of the die casting mold temperature machine
The function of the die casting mold thermostat is to keep the temperatures Jo and Jm constant, preventing the temperature difference Jo-m from expanding or decreasing during production or shutdown.
The temperature of the mold is a key factor in the heat dissipation of the metal solution, mold filling, and solidification process of the casting.
When the mold temperature is too high
Difficulty in taking parts due to thermal deformation or mold sticking
The sprayed release agent cannot generate a protective film on the surface of the mold cavity, increasing the consumption of the release agent
3. Die casting cycle prolongation due to die casting mold wear
4. The temperature difference between the moving mold and the fixed mold causes mold deformation
5. Reduced accuracy, scarring, shrinkage, and increased porosity
When the mold temperature is too low
1. It is difficult to take parts due to shrinkage, and the mold is stuck
2. Reduced performance of release agent
3. Defects such as cold shuts or insufficient mold filling
Increased thermal shock leads to mold wear
5. The surface of the die casting is embedded with cold beans or flow marks
6. Reduced accuracy
7. Cold lines, cracks, and cold shuts during die casting
Comparison of Thermomechanical and Release Agents for Die Casting Dies
Spraying a large amount of release agent can also reduce mold temperature, but spraying excessive release agent can cause porosity defects in castings and shorten mold life. Because the surface temperature of the mold cavity decreases below the allowable value, the stress generated on the surface is concentrated. If a die casting mold temperature machine is used, controlling the mold temperature internally can avoid excessive use of mold release agents for cooling purposes.
Working objectives of die casting mold temperature machine
Heat the mold and stabilize it to the required working temperature to achieve the effect of shortening the die casting cycle, stabilizing the casting quality, and extending the mold life.
The Practicality of Die Casting Die Temperature Machine
It plays an important role in the startup process, production process, and cooling process.
Startup process
The following is an example of "die cast aluminum alloy elevator pedals":
When die-casting aluminum alloy elevator pedals, if you do not use a die-casting mold warming machine when starting the machine for the first time, but directly preheat them with aluminum water, the temperature of the mold can only be raised to the required working temperature for the product if more than a dozen molds were previously die-cast.
1. Serious impact on work efficiency.
2. If the price of the first mock examination is about 300 yuan, 4000~5000 yuan will be lost during preheating. When the mold is turned on and preheated, using a die casting mold warmer can reduce the scrap rate of pressed products.
Production process
Because the heat in the die casting mold basically comes from liquid metal, even if production is stopped for only a few injection cycles, without the aid of mold temperature control, the mold temperature will also drop sharply, and the casting scrap rate will immediately rise significantly.
cooling process
In addition to the function of preheating, the die casting mold heater also has a cooling function. And the temperature control accuracy reaches ± 1 ℃, which can completely replace the original simple water cooling method, helping customers to mold better products.
Advantages of using mold temperature machines in die casting processes
1. Extend mold life
2. By making the mold heat distribution more uniform, the mold life can be extended;
3. Preheating the mold evenly and smoothly to eliminate stress cracks - Preheating the mold with flame often causes local overheating or thermal shock caused by gap water cooling, which is overcome by using a mold warming machine to preheat;
4. Lower costs The mold is in good condition and the number of repairs will be reduced;
5. The amount of release agent decreased;
6. The casting quality is stable, which can reduce the inspection frequency and inspection cost;
7. Shorten warm-up time;
8. The mold temperature is constant and within the process requirements, and liquid metal is not easy to adhere to the mold;
9. Uniform temperature, low wear of mold accessories;
10. Using heat transfer oil, the cooling channel will not rust or scale, while water cooling will easily cause the channel to rust and block.
11. Increase productivity:
(1) Preheat the mold quickly and purposefully before production begins;
(2) At the beginning of production, the mold temperature is constant, and waste products are reduced - there is no need for many mold heats and low speed injection;
(3) Automatic mold temperature control, independent of the production process, ensures stable casting quality;
(4) Production interruption and restart reduce scrap - the mold will maintain thermal stability;
(5) Shorten the beat and achieve energy-saving effect.
12. Improve die casting technology
(1) Temperature control does not rely on operators;
(2) The mold temperature is relatively constant and can be adapted to die casting thin-walled castings;
(3) Reduce heat emission and improve the production environment;
(4) Fully automatic operation, mold temperature can be automatically controlled;
The practice of die casting has shown that when the alloy melting control is qualified, casting defects are mainly caused by abnormal mold temperature. The mold temperature machine can effectively help the die casting process control mold temperature within a reasonable range, which can reduce the scrap rate. During the die casting process, the mold initially needs to be preheated. In the past, it was often used to raise the mold temperature by pouring several mold alloy solutions, which was time-consuming and costly. Using a mold warming machine, mold preheating can be directly heated to the desired temperature using a mold warming machine, and no waste products will be generated during the preheating stage; The mold temperature machine can reduce the scrap rate to 80%, shorten the heating time by 30%, and extend the service life of the die casting machine by two to three times. The traditional die casting process uses water cooling, which has a large temperature difference between the mold and the cooling water, easily leading to mold cracking. Using a mold temperature machine, its oil outlet temperature accuracy can reach ± 1 ℃, and the temperature difference between the mold and the heat transfer oil is small, which will not lead to mold cracking.
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