Spraying is one of the essential processes in the production of aluminum alloy die-casting. Its usage can be roughly divided into four methods: automatic spraying (mechanical arm), manual spray gun, brush, drip, etc. Among them, automatic spraying and manual spray gun spraying are the most common. The spraying effect of manual spray guns is most easily affected by human factors and equipment. If the spraying effect is not ideal, it can directly lead to defects such as burns and cracks on the castings, causing significant losses to die-casting production.
Here are a few important factors that affect the spraying effect of manual spray guns:
1. Human factors
In terms of manual spraying, spraying technology can measure the skill level of a die-casting worker and also reflect their experience. Some basic principles or experiences are followed by everyone:
A、 Focus on spraying on areas with high temperatures
B、 Key spraying areas for easy to pull molds
C、 In addition, the temperature during the production process may change, and die-casting workers need to observe more: for example, if there are areas that turn white, it is important to focus on spraying.
D、 The pressure and direction angle of spraying will have a significant impact on our spraying effect, and can be adjusted to see the effect.
E、 Observe more, summarize more, adjust more, each product is different, and master the rules well.
2. Spraying equipment and process factors
The common method for manual spraying is the three-level spraying process:
Jet first: How many functions does jet have here
A、 Remove residue and debris from the upper mold, especially from the exhaust and corners
B、 Plays a certain air cooling effect
Post spray release agent: Reduce mold temperature to form a continuous mold on the surface of the mold
Jet again: This step has the following functions
A、 Make the areas that are not easy to spray evenly sprayed under the action of air pressure
B、 Quickly diffuse the evaporated water vapor and other substances after spraying the mold release agent out of the mold cavity to prevent reaction with the alloy liquid
C、 Has the effect of accelerating cooling
3. Other process parameters for spraying
Spray amount of release agent:Excessive spraying not only causes waste, but also easily leads to mold accumulation; Insufficient spraying can easily lead to mold pulling. So during the use of release agents, it is necessary to control the spraying amount to a critical point.
Testing method for critical point:Gradually reduce the amount of release agent sprayed while ensuring that the mold is not pulled, until the amount of release agent sprayed is reduced to a point where it cannot be further reduced.
Spray pressure:Higher air pressure can produce better atomization effect, increase the wettability of the release agent, and bring out more heat.
Spray distance:Control the spraying distance to ensure that the release agent is sprayed onto the entire surface of the mold.
Spray time:The optimal spraying time is generally 1-2 seconds.
In addition, factors such as the angle of spraying also affect the spraying effect of the release agent, and it is necessary to make more attempts in the workshop to determine a reasonable process.
