China construction machinery industry has jumped to the top in the world, becoming an important pillar industry for the development of China's national economy.

According to predictions, the domestic sales scale will reach 900 billion yuan by 2025, the international demand for mainframe products will reach 210 billion US dollars, and China's exports of construction machinery products will reach 26 billion US dollars, making it a major exporting country in the world.

The total scale of the construction machinery industry has jumped to the top in the world, becoming an important pillar industry for the development of China's national economy.

The development of the construction machinery industry has shifted from extensive, imitative, and quantitative to technological innovation, quality and efficiency, and aesthetic and environmental protection. The construction machinery industry is undergoing a transformation during the 12th Five Year Plan period The goal of technological development is to prioritize technology and focus on low-carbon, green, efficient, energy-saving, and information technology projects. To achieve the development goals of energy conservation, consumption reduction, and emission reduction, on the one hand, product structure optimization and lightweight design can be carried out to reduce exhaust emissions; on the other hand, traditional manufacturing processes can be transformed to increase specialized production scale, and energy-saving, environmentally friendly, and low-carbon process equipment can be used for product manufacturing in the production process. Coating technology is precisely the energy consuming and environmentally friendly key link in the manufacturing process. Therefore, it is imperative to apply energy-saving, environmentally friendly, and low-carbon coating technology in industries such as construction machinery. This is also the need for China's "resource-saving" and "environmentally friendly" two type society construction.

Characteristics of Coating for Construction Machinery

In recent years, construction machinery enterprises have continuously increased investment in technological transformation, improved production capacity, and continuously updated and improved manufacturing processes, mainly manifested in the improvement of manufacturing quality and surface coating level. From the development of coating technology alone, the open-air spraying process for street vendors has been eliminated, and the coating technology level continues to improve. Coating equipment is becoming more advanced, automated, and efficient. Some parts have been coated with advanced coating technology and equipment in the automotive industry, with more complete processes, more beautiful and weather resistant coatings, more reliable anti-corrosion coatings, and more environmentally friendly coatings and equipment. However, as a large-scale industry, construction machinery is different from other industries such as automobiles, home appliances, and furniture. It has its own characteristics and needs to be carefully studied

1. The types of products and workpieces are complex, and the sizes of workpieces vary. The length of components ranges from a few hundred millimeters to one or twenty meters, and the weight ranges from a few kilograms to twenty or thirty tons. The whole machine ranges from a few meters to fifty or sixty meters, and the weight ranges from a few tons to two or three hundred tons. The plate thickness ranges from one or two millimeters to one or two hundred millimeters.

2. The structure is complex, the workpiece has multiple internal cavities, and the single piece operation time is long.

3. The workpiece has multiple machining surfaces and holes, and the shielding is complex.

4. The supply of sheet metal is poor, mostly using hot-rolled plates and profiles, with severe surface corrosion and uneven pits.

5. The painting process for components and the entire machine is complex and involves multiple procedures. Some components may be coated with a base coat, processed or assembled before intermediate or surface coating; some may be stained during assembly or testing of the entire machine, and even require welding damage during assembly, requiring the entire machine to be re polished before surface coating; and the entire machine or components may require multiple color matching.

All of these pose challenges to the selection of coating process equipment and the application of energy-saving, environmentally friendly, and low-carbon coating technologies.

3、 Application of energy-saving, environmentally friendly, and low-carbon coating technology for painting process equipment

1. Pre shot blasting processing equipment

(1) The production scale of major host or structural component manufacturers now cannot be compared to before the 11th Five Year Plan Large and efficient. For example, excavator factories have a starting scale of over 10000 units/year, and several factories have a capacity of 20000 to 30000 units/year; loader factories The production capacity of a group of military units has reached 30000 units/year, with some factories reaching over 40000 units/year; forklift factories have production capacity of over 10000 units/year, with some factories exceeding 60000 units/year; crane production capacity is mostly over 10000 units/year, with some factories exceeding 20000 units/year; cement mixing and transportation truck production capacity is mostly over 3000 units/year, with some factories already planning a production capacity of 30000 units/year.

Such batches and types require detailed classification of workpieces, especially by cross-sectional size. The cross-sectional size of workpieces in continuous shot blasting chambers affects the arrangement, number, and size of the blasting heads, thereby affecting the dust removal air volume. These two parts of power consumption account for more than 70% of the power consumption of shot blasting equipment.

As for excavators, they have a capacity of over 10000 units per year Two structural component coating lines need to be built, traditionally designed as two universal lines, now designed as: one line for shot blasting and painting on the upper and lower platforms, and one line for shot blasting, cleaning, phosphating, and powder spraying on the boom, boom, and bucket. Only the energy consumption of shot blasting equipment can save 200Kw.

(2) The shot blasting machine adopts a direct connection method to reduce power transmission loss and increase maintenance space.

(3) The use of belt conveyors for pellet recycling reduces equipment failures and saves energy.

Especially for long workpieces such as crane booms, tower crane booms, balance arms, and crawler cranes, the shot blasting equipment and cleaning and spraying equipment are very long. Spiral conveying is often used, requiring 6-8 levels, high power consumption, high failure rate, deep pits, and increased investment. If belt conveying is used instead, it will be more energy-efficient, simple, and practical.

(4) The dust collector must adopt two-stage dust removal: cyclone+filter element. The filter element adopts imported filter paper, automatic pulse back blowing, and the discharge pipe is equipped with detection holes for easy detection. The filter element is maintained and replaced according to requirements to ensure standard discharge.

(5) For suspended through shot blasting equipment, the sealing material and structural type at the top opening need to be continuously improved. Some joint venture companies' sealing structures are worth learning from to effectively reduce the risk of personal injury caused by leaked flying particles and minimize environmental pollution in the workshop. Currently, it is common practice to use composite color plates to create a barrier wall from the separator platform downwards, which can greatly reduce the splashing of flying particles and achieve good results.

(6) The recommended protective material is rolled Mn13, which is impact resistant. The impact of the thrown pellets actually makes it more wear-resistant, significantly improves its service life, and is easy to install and maintain. Welding connection is sufficient.