CIMS Technology in PCB Assembly
In the domestic PCB assembly industry, surface mounting technology (SMT) is rapidly adopted, and domestic STM production lines have reached more than 10,000.
The important processing equipment in PCBA industry belongs to the automatic production equipment controlled by computer.
These automated processing equipment require programmers to spend a considerable amount of time in data preparation and programming before the production of printed circuit boards (PCB).
The vast majority of electronic products manufacturers, especially high-tech enterprises with independent development and design capabilities, have the characteristics of fast product renewal, multi-variety and small batch production.
This requires that the production preparation time of processing equipment is short and the effective production time is long, so as to meet the requirements of the above production characteristics and shorten the research and development of products and the period of putting them into the market.
How to establish organic information integration and sharing between CAD design system and automatic production equipment, connect design automation and production automation to information flow, and dismantle the "partition wall" between product design and product manufacturing is exactly what computer integrated manufacturing system (CIMS) technology needs to solve.
In PCBA industry, CIMS is a paperless manufacturing information system which can improve the quality, capability and output of circuit assembly. The system can control and monitor assembly line equipment such as screen printer, dispensing machine, mounter, plug-in machine and test equipment. Once a problem occurs, CIMS can feed back the information to the operator or process engineer and point out the exact location of the problem. A relatively complete CIMS system should have the following four elements:
Firstly, the system realizes the information integration of CAD and Computer Aided Manufacturing (CAM), which is the most basic part of CIMS system. The information integration between automatic design and automatic manufacturing subsystems can help to realize the automatic conversion from CAD data to manufacturing data needed by production equipment, that is, to realize automatic programming. This function makes the product conversion on the production line quite easy. Once on-line products have conversion requirements, they can be automatically reflected in machine programs, test data and documents through CIMS system, without programming or modifying settings for each device. This means that product conversion can be achieved in the past few hours or even days, and now it can be achieved in a few minutes. This paper will focus on how to realize the integration of CAD/CAM in the following chapters.
Secondly, CIMS should provide tools for manufacturability analysis and testability analysis.
By analyzing the manufacturability of the CAD files from the design department and feeding back the problem of violating the mounting rules to the design system, the concurrent engineering of the design and manufacturing system can be promoted and the one-time success rate of the design can be improved.
The testability analysis tool can provide a complete testability analysis report for designers, so as to arrange testing and testing resources reasonably and effectively, and help design engineers to improve the testability design of products.
Thirdly, CIMS can provide a reference for production scheduling. By considering the parameters of products to be assembled, machine occupancy and delivery cycle requirements, the system will maximize the efficiency of production and assembly. CIMS can be used for both direct short-term scheduling and long-term strategic consideration of plant capacity.
Finally, CIMS should help to balance the production line and optimize the process. One of the main features of CIMS is to optimize the assembly by automatically balancing the loading and sequencing of products, the allocation and mounting of components and the speed of equipment. At the same time, the system should be able to make a reasonable choice between allocating components to the appropriate machine or using manual assembly.
With the help of relevant national organizations, many typical CIMS application projects have been established in China's machinery manufacturing industry.
Beijing Machine Tool Factory and Huazhong University of Science and Technology have won the International CIMS Promotion and Application Award successively, which indicates that China has entered the international leading level in CIMS research and development and promotion. However, few factories in the electronics manufacturing industry actually implement CIMS project.
Recently, SMT technology is being rapidly adopted in PBCA industry in China.
In recent years, tens of thousands of advanced SMT automation production lines have been introduced, which are basically computer-controlled automation equipment, creating favorable conditions for the implementation of CIMS project in PCBA industry.
In view of the specific situation of PCBA industry in China at present, accepting the experience and lessons of CIMS implementation in machinery industry in recent years, the implementation of CIMS project in PCBA industry is not necessarily comprehensive, but the key is the application of CIM. The application of CIM technology in PCBA industry makes enterprises have the characteristics of multi-variety and small batch production, and improves the ability of enterprises to respond to market changes quickly, so as to enhance the competitiveness of enterprises in large-scale global production.
From PCB design to assembly, CIMS provides a powerful tool for PCBA manufacturers. CIMS can provide complete solutions regardless of the variety of components, the type of substrate, the size of PCB board and the process used.
At the same time, CIMS is also the link of heterogeneous equipment integration, providing guarantee for rapid product conversion, quality and output improvement.
