Robotic Painting Technology And Future Development

Compared with manual painting, robotic painting has many advantages and has become increasingly popular in the industry in recent years. my country's industrial robots began to develop in the 1970s, among which the automobile industry was the first field to be piloted, and automatic painting equipment such as spray painting robots have been put into use one after another. The use of paint during robot painting is reduced, which is conducive to energy conservation and emission reduction; product quality, qualification rate and stability are improved; manual operation is reduced and labor production efficiency is improved. Painting robots are mainly divided into electronic control systems, camera systems, automatic spraying systems, ground feeding systems, safety anti-fall systems and climbing systems. At present, the manufacturers of painting robots are mainly concentrated in Europe and Japan. The price of European systems is relatively high and the performance is good. The Japanese systems are cost-effective and have an advantage in market share.

Robotic coating technology is used in general fields such as automobiles, home decoration, and electronic products. Spraying robots for automobile painting are the most common. Wall crawling robots are used for exterior wall painting of high-rise buildings. In addition, there are painting robots for large aviation parts, painting robots for inner and outer panels of ship docks, painting robots for rail vehicle bodies, and painting robots for nuclear power maintenance. Painting robots have urgent application needs in painting operations such as high-altitude buildings, narrow and confined spaces, pipeline inner wall anti-corrosion, high radiation and high-risk areas.

Painting process

The main parameters affecting the robot spraying process are: rotary cup speed, flow rate, molding air, electrostatic voltage, bearing air pressure and spraying distance. These parameters have a great influence on the quality of the paint film, and paint film defects such as sagging, orange peel, flowery, and color difference may occur. For example, a large flow rate will cause defects such as sagging and bubbles, and the rotary cup speed should be moderate. If the speed is too high, the coating film will become thinner and the paint will rebound. Color performance is the key to the beauty of the coating, and color difference will also occur in robot painting. Changes in spray color without cleaning, spray pipes without cleaning, and changes in paint structure caused by long-term spraying will cause color difference. The research hotspots of spraying robots are mainly trajectory optimization and spray gun modeling analysis. The continuous changes of mathematical algorithms and computational models have promoted the continuous development in this area. Domestic research on spraying robots mainly focuses on robot configuration and motion simulation, solving a series of kinematic and dynamic problems.

Research progress

Foreign countries have studied painting robots earlier. China began to use electro-hydraulic servo drives, which belong to the first generation of painting robots. At the same time, foreign countries used AC servo drives, which can improve the reliability of robots, reduce energy consumption, and reduce maintenance. The spraying process of painting robots has developed from manual guidance at the beginning to offline programming and automatic painting of the entire production line in the late 1980s. Offline programming can reduce the online debugging time of painting robots. Automobile painting robots are mainly used in the painting of car body topcoat, axle and other parts, and gradually developed an automated painting system for the whole vehicle.

The painting process generally requires surface treatment, paint application and surface inspection. Different painting robots have been developed for different painting links. Painting wall-climbing robots can replace workers in high-risk operations. The two major functions of wall-climbing robots are attachment and movement. A lot of research and improvement work has been done in the fields of mechanical and computer engineering. Harbin Institute of Technology in China has been engaged in the research of wall-climbing robots since the late 1980s and has developed multiple series and varieties of wall-climbing robots. Harbin Institute of Technology and Daqing No. 1 Oil Production Plant jointly developed my country's first crawler-type magnetic adsorption wall-climbing robot for spray painting and anti-corrosion. In addition, Harbin Institute of Technology has developed underwater cleaning robots for hull surfaces, opening up a new direction for underwater surface treatment and painting of ships. For wall-climbing painting robots, obstacle crossing technology is a problem that needs to be solved. These conditions can be improved through propeller thrust adsorption devices and omnidirectional walking mechanisms, and the robot's adaptability and obstacle crossing ability on complex surfaces can be improved.

For the painting of the inner and outer panels of ships in the dock, there are mainly grinding, sandblasting, rust removal, painting and other processes. There are three main types of spraying robots in ship docks: wall climbing, frame track, and elevated vehicle. Rust removal robots are also available in conjunction with spraying robots. There are many studies and rich products. In 2018, the rust removal and wall climbing robot developed by the 716 Research Institute of China Shipbuilding Industry Corporation was successfully tested for the first time in Wuhan Shipbuilding Company. Typical providers of painting robot products include the VM400 series of Urakami Research Institute in Japan, the Ship system series developed by Palfinger in Austria, and the spraying robots of Syncroil in Spain and Rina Vincenzo in Italy. In addition, the Daegu Institute of Electromechanical and Materials in South Korea has also developed an intelligent wall-climbing type dock inner and outer panel spraying robot.

In some other special fields, the demand for painting robots is more prominent. For example, aviation parts have extremely high requirements for the thickness, uniformity and stealth conditions of the coating. Robotic automated painting is an important direction for the development of my country's aviation manufacturing. At present, China is in the initial stage of using painting robots in the aviation manufacturing industry. In 2015, Shanghai Aircraft Manufacturing Co., Ltd., Tsinghua University and equipment companies jointly developed a hybrid robot for spraying aircraft wings and other parts.

Future Trends

The development of robot painting technology has increased the utilization rate of paint, reduced production costs, and is more energy-saving and environmentally friendly. With the continuous updating and iteration of technology, the control technology and software level are constantly improving, and the application performance of painting robots will be further improved and more intelligent. In the future, the demand for personalized painting and small-batch production of painting robots will increase, and the requirements for precision and stability will also become higher and higher. my country's painting robots need to be based on the specific requirements of my country's coatings and industry development, make good use of existing technologies and special advantages, and combine the continuous development of artificial intelligence, Internet of Things, cloud computing, long-life batteries and other advanced technologies to accelerate the research and development of painting robots, achieve overtaking on the curve, and try to innovate and upgrade, break through the shackles of existing technologies, and find a distinctive development path.