In recent years, as China's manufacturing industry has continuously improved, CNC plasma cutting machines have become widely adopted in industrial enterprises, significantly enhancing the overall level of the country’s machinery manufacturing sector. However, the large amount of smoke produced by these machines during operation often spreads throughout the workshop, posing serious health risks to workers and contributing to atmospheric pollution. As a result, more and more companies are now paying close attention to dust and fume control in modern industrial settings.
**1. Dust and Hazards in Modern Industrial Workshops**
Welding equipment such as manual arc welders, COâ‚‚ gas shielded welding machines, TIG welders, and submerged arc welders generate significant amounts of welding fumes. In metal cutting processes, many companies use CNC plasma cutting machines for precision. During plasma cutting, a large amount of soot is created due to the melting of metal and high-speed gas collisions. Similarly, metal grinding operations also produce substantial amounts of metal dust.
The harmful gases and fine particles generated from welding, cutting, and grinding are typically very small, with about 70% of the particles measuring less than 0.5 microns and 30% larger than 0.5 microns. These particles can remain suspended in the air for long periods, making them highly dangerous. The effects on human health include damage to the central nervous system, respiratory issues, and skin irritation. One hour of welding is equivalent to smoking 58 packs of 20 cigarettes in terms of risk.
Scientific research shows that cutting dust contains various inhalable substances like manganese oxide and potassium/sodium oxides. Once inside the body, these can cause severe harm. Prolonged exposure to smoke from portable CNC cutting machines increases the risk of chronic bronchitis and other respiratory diseases. These substances can accumulate in bones and blood, leading to organ dysfunction and even cancer. With the increasing use of cutting materials containing elements like chromium, manganese, and nickel, the impact of cutting fumes on occupational health is becoming more severe.
As shown in Figure 1, the light emitted during plasma cutting fills the entire workshop, highlighting the need for effective dust management.
It is clear that these dusts are extremely harmful. Therefore, it is essential to implement effective treatment methods to improve the working environment and reduce atmospheric pollution.
**2. Main Methods for Controlling Dust from CNC Plasma Cutting Machines**
Since plasma cutting produces a large amount of toxic gases, most Chinese enterprises use either wet or dry dust removal methods.
**1. Wet Dust Removal Method**
The common practice in China is to create a water-cutting platform before using the CNC plasma cutter. The material is placed on the surface of a sink or in water during cutting. If placed above the water tank, smoke is reduced but some still escapes due to compressed air. If the material is cut underwater, the harmful gases are minimized, but this method reduces cutting speed, increases loading/unloading time, and poses explosion risks for certain metals like aluminum and magnesium. Additionally, water pollution is a concern due to the complex chemical composition of the dust, making treatment costly.
Figure 2 shows a typical wet cutting platform.
**2. Dry Dust Removal Method**
This method involves installing a dust collection device on the CNC cutting platform, which directly transports the collected dust to a filter purification system before discharge. Since the smoke from plasma cutting forms mainly under the workpiece slit, a vacuum cutting platform with negative pressure is commonly used. To save costs and improve efficiency, only the area being cut is ventilated, dividing the platform into several enclosed sections with air outlets. This method is popular due to its simplicity, reliability, and effectiveness.
Figure 3 illustrates a single-side lower exhaust dry dust removal system.
**3. Filter Cartridge Dust Collectors for Plasma Cutting Dust**
Plasma cutting dust removal is typically done through direct suction or blowing methods.
**Suction Type**
- **Direct Suction Dust Removal System**: This system includes single-side, double-side, and four-side configurations, depending on the size of the cutting platform.
- **Single-Side Direct Suction**: Used for platforms up to 3 meters wide, with air vents on one side.
- **Double-Side Lower Damper**: Suitable for platforms between 3 and 5.5 meters wide.
- **Four-Side Lower Damper**: For wider platforms, with additional ducts in the middle.
- **Double Suction System**: Uses a sliding suction channel on one side and a fixed blower on the other, ensuring efficient dust removal with minimal airflow.
**Blowing Suction System**: Designed for smaller platforms, with dust collection units mounted on the gantry itself.
Figures 4–7 illustrate different types of suction systems.
**4. Comparison of Dust Removal Before and After Activation**
Figure 8 shows the difference in dust levels before and after the system is turned on.
**5. Key Features of Filter Cartridge Dust Collectors**
- **Filter Cartridge Selection**: Two main types are used: membrane polyester filters and flame-retardant nano filters. Flame-retardant nano filters offer higher filtration efficiency (up to 99.9%) and longer lifespan compared to traditional filters.
- **Automatic Cleaning Device**: Equipped with a PLC-controlled pulse jet cleaning system. When pressure differences exceed set values, compressed air is used to clean the filters, ensuring continuous efficiency and low maintenance.
Figure 9 shows the internal structure of a filter cartridge dust collector.
In conclusion, the author has gained extensive experience in CNC plasma cutting and dust removal over the years. With growing government emphasis on environmental protection and increased awareness among enterprises, the treatment of pollution sources like cutting, welding, grinding, and painting will continue to improve. As a result, the application of advanced dust removal technologies, such as those used in CNC plasma cutting, will become increasingly widespread.
ZHEJIANG KINGSIR VALVE CO., LTD. , https://www.cn-kingsir.com