Problems and Analysis in the Development of China's Construction Machinery Maintenance Industry

I. Transformation of Maintenance Concepts

The idea of post-event maintenance

In the early 20th century, the maintenance of construction machinery was generally carried out after a malfunction occurred, that is, post-event maintenance. Its greatest advantage is that it fully utilizes the lifespan of components or system parts. However, post-maintenance is unplanned maintenance, which wastes a lot of remaining repairs. At the same time, it also has certain defects and deficiencies.

2. Maintenance philosophy that prioritizes prevention

In the 1950s, people's understanding of the wear mechanism of equipment deepened further: components work - wear occurs - failure occurs - affecting usage and endangering safety. To ensure that each component is reliable and safe in use, maintenance work must be carried out before faults occur, thus forming a maintenance concept that prioritizes prevention. This maintenance concept encompasses the idea of proactive prevention. Its essence is to eliminate faults in their infancy by taking various preventive measures, thus changing the passive situation where post-maintenance lacks planning. However, this maintenance ideology also has certain limitations, mainly manifested in three aspects: First, maintenance work is guided by direct experience and can only put forward general maintenance principles, lacking pertinence; Second, they only focus on solving specific technical problems in maintenance, neglecting the overall connotation of maintenance and lacking research on maintenance management. Due to the difficulty in predicting a large number of random faults in advance, even though a lot of preventive maintenance work has been done, it is still hard to achieve the expected results. Thirdly, the rigid implementation of timed and fixed-distance maintenance, such as disassembly and inspection maintenance, inevitably leads to frequent disassembly and assembly in maintenance work. This results in poor targeted maintenance, heavy workload, long time consumption, and high costs. Moreover, disassembly and assembly may also plant new potential faults, significantly reducing the reliability of mechanical equipment.

3. Maintenance philosophy centered on reliability

Over the past two or three decades, based on the maintenance philosophy of prevention first, modern management science has been applied, and advanced testing techniques and diagnostic methods have been widely adopted, gradually forming a maintenance philosophy centered on reliability. This maintenance concept takes the system monitoring of the maintenance object as a means, replaces the off-position detection with a large number of in-situ detection, and changes the single timed and fixed-range maintenance to the maintenance based on reliability data analysis. It makes the maintenance work more targeted, makes the subjective and objective more consistent, enhances the scientific nature and reduces the blindness. The basic points are as follows:

① Maintenance work is based on reliability theory. From the selection of maintenance timing, methods, cycles, the calculation of maintenance workload, and the definition of maintenance scope, to the reliability coefficient of a single component after repair and the standards for diagnostic inspection of a project, all should be based on ensuring and enhancing the overall reliability of the equipment.

The reliability of construction machinery is determined by a combination of three factors: design, manufacturing and usage. Therefore, to enhance its reliability, efforts must be made from these three aspects. Reliability maintenance can maintain and restore the performance of machinery, and can provide extremely valuable data information for design, manufacturing and usage units to improve the overall reliability of equipment.

③ Reliability indicators are the most scientific and effective basis and standard for evaluating maintenance quality.

In conclusion, the maintenance concept centered on reliability follows the pattern of equipment failure, enhances the pertinence and flexibility of maintenance, improves the efficiency and effectiveness of maintenance, and enables maintenance work to achieve its ultimate goal and meet the overall requirements.

Ii. The Current Situation of the Maintenance Industry

Abroad, industrialized developed countries all attach great importance to the development of the maintenance industry. They have dedicated maintenance management institutions, and maintenance enterprises come in various forms. The maintenance market has become relatively mature, and private maintenance groups have a history of over 40 years. They often hold exhibitions of maintenance equipment and large-scale academic conferences on maintenance theory and technology, which has effectively promoted the development of the maintenance industry. In the early 1970s, the research and application of construction machinery maintenance in our country entered a period of relatively rapid development. Research institutions and academic groups were established, and new equipment and new processes for maintenance were promoted and applied, achieving certain results. At present, the maintenance industry of construction machinery in our country is still not standardized enough, mainly manifested in:

One is that the macro management of the construction machinery maintenance industry lacks a unified department in charge. At present, the construction machinery maintenance industry is managed by several departments such as national ministries and commissions and the administrative department for industry and commerce. The power is scattered and the responsibilities are unclear, making it difficult to coordinate and unify policies, which has led to a "vacuum zone" in the management of maintenance industry personnel in our country.

Second, there is a lack of laws and regulations to protect the normal development of the maintenance industry, which makes the development of the maintenance industry lack a basis and rules to follow.

Thirdly, the nature of construction machinery maintenance enterprises is relatively single, basically limited to medium and small-sized maintenance enterprises of collective and private nature, and their awareness of financing is weak. Fourth, the competition, evaluation, supervision and incentive mechanisms for the maintenance industry have not yet been established. The standards and systems are not yet complete, and there is no basis for the evaluation of maintenance quality.

Iii. Reform Ideas for the Maintenance System

The reform of the maintenance system affects the normal operation and healthy development of the maintenance industry. To ensure the coordinated development of the maintenance industry of construction machinery and the manufacturing industry, it is necessary to establish an appropriate maintenance system. First, it is necessary to establish a management department with unified responsibilities and authorities as soon as possible, which is responsible for the macro-control of the construction machinery maintenance industry and the planning of its overall development. Second, efforts should be made to enhance legislation and law enforcement in the industry, formulate systematic and complete regulations, systems and standards, so that the maintenance industry has laws to abide by and evidence to rely on, and accelerate the pace of development from administrative command-based to law-based management. Third, actively create an external environment conducive to the diversified development of the construction machinery maintenance industry. Formulate fiscal and tax preferential policies to support the development of the maintenance industry, rationally introduce foreign capital, intensify mergers and reorganizations, and change the current situation where the nature of maintenance enterprises is relatively single.

Flexible and diverse management forms have gradually formed a situation where joint ventures, sole proprietorships, collectives and private enterprises coexist, compete and complement each other. Fourth, promote the development of the construction machinery maintenance industry from professional separation to resource sharing. Modern equipment integrates mechanical, electronic, hydraulic, computer and sensor technologies, which puts forward higher requirements for maintenance. Maintenance enterprises that can only complete a single profession and trade will face severe challenges. Meanwhile, repetitive investment will cause huge waste of resources. Enterprises with a small amount of maintenance resources can only adapt to the development trend by achieving resource sharing and complementary advantages. Fifth, transform the traditional fixed-point maintenance method into a combination of fixed-point maintenance and mobile maintenance, form professional mobile maintenance teams, and equip them with high-performance mobile maintenance equipment to provide on-site maintenance services.

Iv. Development Direction of the Maintenance Industry

It mainly focuses on the technologies of condition monitoring and fault diagnosis

With the development of science and technology, especially the rapid growth of microelectronics, computers and information technology, the application of opto-mechanical integration technology in construction machinery will become increasingly widespread. At present, the technologies for condition monitoring and fault diagnosis have made considerable progress. Practice has shown that the more advanced the performance of construction machinery is, the more complex its structure becomes, and the more its maintenance activities rely on condition monitoring and fault diagnosis technologies. Post-event maintenance, preventive maintenance, and the idea of maintenance centered on reliability each have their own advantages and disadvantages and certain applicable scopes. Mechanically stipulating that a certain maintenance unit or a certain model can only adopt a certain maintenance method is not only impractical but also ineffective. At present, the maintenance of construction machinery in developed countries is mainly based on condition monitoring, centered on reliability maintenance, and combines multiple maintenance methods. Different methods are adopted for condition-based maintenance according to different situations. In the future, with the wide application of condition monitoring and fault diagnosis technologies, advanced construction machinery will be equipped with online automatic monitoring and fault diagnosis instruments and equipment that integrate mechanics and electronics. The maintenance concept centered on reliability will become the dominant ideology in the maintenance management of construction machinery.

2. Establish an intelligent network maintenance service system

Establishing an intelligent network maintenance service system will become a key development direction for the construction machinery maintenance industry in the 21st century. In Switzerland, the construction machinery maintenance service network has spread throughout the country. There are parts center warehouses in each region. Business personnel can grasp the distribution of maintenance stations and certain parts across the country in just two or three minutes. By applying network technology, it is also possible to transcend national, regional and temporal and spatial boundaries, connecting research institutions, technical consulting firms, manufacturing plants, repair shops, parts stations and user units of construction machinery, and achieving remote, fast, high-quality and all-round services. The manufacturer takes this as the main means of after-sales service. Through the data acquisition system, transportation management system and maintenance service system that are matched with the construction machinery, it directly or indirectly acquires information from the construction site and completes the after-sales service in the most efficient way.

3. Develop improvement-oriented repair and composite restoration processes

Traditional restorative repair can only make the performance of faulty machinery approach that of the original machine after repair, without taking into account the factor of technological progress. Improvement repair involves using new devices, materials and technologies to fix old machines, so that the repaired old machines can fully demonstrate their capabilities and reach or approach the performance of new machines. In the future, with the wide application of electro-hydraulic technology, CAD technology and materials engineering technology in construction machinery, the update cycle of new types of construction machinery with integration and intelligence will be further shortened, and restorative repairs will be increasingly replaced by improvement-oriented repairs. In addition, there are composite repair methods that use two or more repair processes to repair parts or equipment, such as: welding + adhesive, multiple surface repair techniques, etc. They can integrate the strengths of various methods and make up for their weaknesses, and have the best economic benefits. They will become the key research and development direction of repair technology.