European Classroom | The development of product assembly technology, key technologies and future trends
Assembly
is a key link in the product development process. The parts are assembled according to the specified technical requirements, and then debugged and tested to make them qualified products.
2021
Oct.5
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According to statistics, in the modern manufacturing process, assembly workload accounts for 20% to 70% of the entire product development workload, and assembly time accounts for 40% to 60% of the entire manufacturing time. The assemblability and assembly quality of the product not only directly affect the product performance , but also have important engineering significance for improving assembly production efficiency and assembly quality .
Product assembly technology has become an important part of industrial production. This issue of the European Classroom will provide a comprehensive analysis from three aspects: the development of product assembly technology, key technologies and future trends .
Development of product assembly technology
The early stage of the development of the machinery industry
When factories were still in the single-piece production mode, workers had high skills in design, machining and assembly. At this time, most workers were familiar with the principles of design and the properties of the materials used , and were skilled craftsmen.
After World War I
The emergence of mass production has led to the widespread application of the idea of division of labor , and a group of new professionals have emerged. This professional division of labor is not only carried out in the workshop, but also in the engineering department . For example, workers are divided into machine operators, quality inspection workers, etc.; engineers are divided into structural design engineers, process engineers, etc.; engineers are further divided into engine design, body design, electrical system design, etc.
With the development of large-scale production methods, assembly has gradually formed a division of labor among assembly workshop management engineers, assembly process design engineers, assembly quality inspection engineers, and workshop assembly operators. It has also formed an academic and engineering team with product assembly technology as the main research direction , which has effectively promoted the development of assembly technology.
Key technologies for product assembly
In terms of product assembly technology, domestic and foreign scholars have achieved a series of research results. The following is an analysis of the research status of related results from six aspects: assembly-oriented design, digital assembly, assembly connection process, assembly process equipment, assembly measurement and detection, and assembly MES .
Design for Assembly
Design for assembly (DFA) mainly takes product structure design as its starting point, considers the assemblability of its product parts, assembly cost and time, assembly sequence and path and other related issues, and provides a series of analysis and evaluation criteria and methods for assembly design to help designers conduct a comprehensive analysis of product assemblability.
On the one hand, it provides reasonable modification suggestions for product design , and on the other hand, it provides guiding assembly sequence and assembly path and other process parameters for formulating product assembly process regulations .
Digital assembly technology
The emergence of computers and digital technology has greatly promoted the rapid development of assembly technology. Digital assembly is the result of the intersection, integration, development and application of product assembly technology with computer technology, network technology and management science . It is the combination of digital technology and traditional assembly technology, namely digital assembly technology:
Based on the product digital prototype, we carry out product coordination scheme design and assemblability analysis, and plan, simulate and optimize the assembly sequence, assembly path and assembly accuracy, so as to effectively improve the product assembly quality and efficiency.
Assembly connection process
In product assembly, various connection methods are widely used to connect separate parts together. The most commonly used connection methods include threaded connection, welding, riveting and adhesive connection.
Threaded connection is one of the most widely used connection methods in mechanical products. It can obtain great connection force, is easy to disassemble and assemble repeatedly, has the advantages of interchangeability, easy mass production, and low cost; riveting process is widely used in aviation, aerospace, textile, automobile and shipbuilding fields because of its simple molding, low cost, stable connection strength, high temperature resistance, and corrosion resistance.
Assembly process equipment
The design process of assembly process equipment is closely related to the product structure to be assembled, assembly process and testing technology. The differences in product structure and process make assembly process equipment a special kind of machinery.
In the future, assembly process equipment will develop in the direction of high reliability, automation, flexibility, intelligence, and application integration . At the same time, the complexity of assembly process, uncertainty of structure and process parameters also require assembly process equipment to achieve system integration with process and detection technology during the development process.
Assembly measurement and inspection
According to the different measurement objects, assembly measurement and inspection technology is mainly divided into three categories: ① measurement of geometric quantities , that is, measurement of product shape and position; ② inspection of physical quantities , that is, inspection of assembly force, deformation, residual stress, quality characteristics, etc.; ③ inspection of state quantities , including inspection of product assembly status, interference conditions, sealing performance, etc.
The measurement and detection methods and tools involved in the above-mentioned detection objects are different and need to be reasonably selected according to the specific circumstances.
Assembly MES technology
Manufacturing execution system (MES) is a production information management system for the workshop execution layer that has developed rapidly in recent years .
Assembly MES technology usually includes functions such as assembly workshop operation planning, assembly quality analysis, assembly cost control, dynamic material tracking and management, and workshop equipment capacity management. Assembly MES technology can effectively improve the production efficiency of the assembly workshop and ensure product assembly quality .
Future trends
At present, the assembly management in China's product production is backward and the automation level is low. Only some industries such as automobiles and electronics have achieved automated assembly. Most products in the aviation, aerospace, military, shipbuilding, CNC machine tools, engineering machinery and other industries are mainly based on experience-guided manual assembly operations . The assembly process parameters are mainly adjusted by experience and feeling, and the level of assembly adjustment mainly depends on the experience and skills of the workers, resulting in uneven product assembly quality .
With the transformation and upgrading of China's manufacturing industry to high-end manufacturing such as intelligent manufacturing, product assembly technology also needs to gradually realize the transformation from manual/experience assembly to automated/intelligent assembly . The development trend of product assembly technology in the future is mainly integration, precision, micro/nano and intelligence .
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