Release Agent For Aluminum Die Casting: Functions & Requirements
Everyone knows that in the process of die casting production,
die casting enterprises use high-temperature resistant die-casting release agents as lubrication media. So why is this? Let's take a look at die-casting release agents together.
Die casting release agents are suitable for
aluminum, magnesium, and
zinc alloy series die casting products, and are currently widely used in industries such as
automobiles, telecommunications, motorcycles, and home appliances. And aluminum alloy die-casting release agent is a necessary auxiliary agent in the die-casting production process. So it is necessary to master the application technology of aluminum die-casting release agent. Due to the varying volume and size, structural complexity, and post-processing requirements of die-casting products, the requirements for release agents also vary.
In die casting production, in order to extend the service life of the mold cavity and punch, ensure smooth demolding of the die casting, and ensure a smooth surface and complete contour of the die casting, auxiliary materials such as aluminum die casting demolding agent and punch lubricant need to be used.
1. Role of release agent:
(1). Good high-temperature lubrication performance;
(2). The mold can be cooled, and the temperature of each part of the mold can be adjusted to achieve relative stability, which is conducive to improving casting quality and production efficiency.
(3). Avoid the direct impact of molten metal on the mold and improve the working conditions of the mold;
(4). Prevent mold sticking;
(5). Reduce the friction between castings and molded parts, as well as the wear of cores and cavities, extend the service life of molds, and improve the surface quality of castings.
2. Requirements for die-casting release agents:
(1). Low volatile point. At 100-150, the diluent can quickly evaporate without increasing the gas in the cavity.
(2). Good coating performance, no accumulation, thin film at high temperatures, easy to clean;
(3). Will not cause corrosion to molds and castings;
(4). The pollution to the environment should be as small as possible, that is, odorless, non precipitation, and non decomposition of harmful gases;
(5). Stable performance, non volatile in the air, no precipitation or decomposition during storage;
(6). Sufficient supply and low price. Generally speaking, water-based release agents have the characteristics of low cost and good volatility, and should be prioritized for selection. It can not only demould, but also adjust the mold temperature, making it convenient and fast. When using release agents, spraying and brushing should not be too thick or uniform.
The aluminum die-casting release agent of the present invention has good adhesion to high-temperature molds, as well as strong heat resistance and crack resistance, forming a smooth blade film that can continuously produce products at high temperatures, and plays a good role in the combination of the release plunger and the mold.
The method of use is to mix the release agent in an appropriate proportion and then spray it onto the mold with a spray gun.
Only by analyzing the advantages and disadvantages of the decompression casting process can the release agent be used correctly.
Advantages of aluminum die-casting release agent:
(1) It can be used to manufacture metal parts with complex shapes, clear contours, thin walls, and deep cavities. Because molten metal maintains high fluidity under high pressure and speed, it is possible to obtain metal parts that are difficult to process through other processes.
(2) The dimensional accuracy of die-casting parts is high, reaching IT11-13 and sometimes IT9, with a surface roughness of RA0.8-3.2m. The interchangeability is good.
(3) High material utilization rate. Due to its high accuracy, die-casting parts can be assembled with only a small amount of processing, and some die-casting parts can be directly assembled and used. The material utilization rate is 60%~80%, and the billet utilization rate is 90%.
(4) High production efficiency. Due to the fast filling speed and short filling time, the metal industry solidifies quickly and the die-casting operation cycle is fast. In various casting processes, die casting has high production efficiency and is suitable for large-scale production.
(5) Easy-to-use plugin. The positioning mechanism is easy to install on the
die-casting mold, and the inserts are easy to insert, meeting the special performance requirements of local die-casting.
The influence of the ratio of die-casting release agent and water on the quality of castings can be roughly divided into the following aspects
1. External cooling of the mold;
2. Forming a skin membrane for demolding purposes;
3. The maintenance function of the mold surface;
4. Smooth effect.
The composition of the die-casting release agent film requires certain conditions:
1. The surface temperature of the mold is between 18O and 250 ℃;
2. Spray evenly onto the mold cavity using a nozzle or manual spray gun;
3. The ratio of water-based coatings should be strict;
If the ratio of release agent to water is too large and the spraying amount is too much, a thicker film will be formed, which will cause slow solution flow and accumulation of the release agent film in die casting, resulting in gas, wrinkles, and sedimentation on the surface of the
die casting part.
If the ratio of the release agent to water is too low or the spraying amount is too small, it will form a thin film, which will cause local oil film cracking, poor release performance, tensile damage, mold sticking, and other phenomena in the die casting. From this, it can be seen that the correct use of water-based release agents has a significant impact on the quality of the die casting.
When using a nozzle or spray gun to spray water-based paint onto the surface of the mold cavity, the particles sprayed reach the surface of the mold to form a water vapor layer. The particles sprayed on will continue to rebound back, which is called the vapor film phenomenon. At a certain temperature below, the water vapor thins, and the sprayed particles can reach the surface of the mold. The components of the release agent begin to adhere to the surface of the model, We call the high temperature when this phenomenon occurs "wet temperature", at which the mold release film begins to form. The "wet temperature" of various die casting release agents is determined by their different composition combinations. Release agents with high wet temperature wet the mold surface in a short time after spraying, and make the surface cool quickly. However, demolding agents with low humidity temperatures tend to have higher temperatures on the surface of the model, making it difficult for the surface of the mold cavity to adhere to moisture, resulting in the slower formation of the demolding film and slower cooling speed.
Metal pressure casting is one of the special casting processes, which has the characteristics of high production efficiency, short production process, high casting smoothness and strength, low machining allowance, and saving metal materials. The water-based release agent has excellent high-temperature film-forming properties, cooling smoothness, water dispersibility, convenient use, and maintenance of the working environment. Its release function is to deposit a dense film with a thickness of only micrometers on the surface of the mold cavity after spraying. In the entire metal
die-casting process, the role of the release agent mainly includes the following three aspects:
1) Before the metal hydraulic injection, it is evenly distributed on the surface of the mold cavity, forming a layer of isolation film between the mold and the metal liquid, preventing the mold cavity from direct erosion by the molten metal liquid.
2) During the die-casting process, it helps the metal liquid enter the mold cavity, ensuring the perfect filling of the mold.
3) After the casting is formed, it can be easily demolded.
Ningbo Fuerd was founded in 1987 and is a leading full-service
die Casting Tooling,
aluminum die casting,
zinc die casting,
and Gravity casting manufacturer. We are a solution provider offering a wide array of capabilities and services that include engineering support,
designing,
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CNC machining, impregnation, tumbling, chrome, powder coating, polishing, assembly, and other finishing services. We will work with you as partners, not just suppliers.
