The advanced surface mounting technology directly affects the efficiency and quality of production. SMT Mounter is the most critical and complex integrated optical / mechanical / electrical equipment in SMT. Generally, surface mount equipment accounts for more than 60% of the total investment of the whole SMT production line. The efficiency and quality of the production line mainly depend on the speed, good and bad of SMT Mounter. At present, the production technology of SMT Mounter in China is gradually in line with the international advanced level. Key technologies include: mechanical movement technology, industrial computer and information processing technology, visual detection and sensing technology, automatic control technology, etc. Next, we will share with you the key technologies of these domestic SMT mounters.

SMT Mounter made in China

1、 Mechanical movement technology of SMT Mounter

In SMT production, because of the high-speed movement of SMT Mounter and the small size of the components, the main executive parts require miniaturization and high-speed. SMT Mounter has the following requirements for mechanical moving parts: (1) design, manufacturing and assembly technology of micro, precision and high-precision mechanical parts; (2) composite transmission technology of fast response, low loss, high efficiency and precision positioning mechanism of moving machinery; (3) high precision, intelligent and high-speed Mounter technology. Mounter is the executive mechanism of SMT Mounter. In order to make SMT Mounter run stably and reach precision requirement, ball screw pair is usually used in SMT Mounter. According to the type of SMT Mounter, we can choose integral guide or movable guide. The new SMT equipment is developing from the traditional single circuit PCB transportation to the multi-circuit PCB transportation structure, and the mounting head is developing to the multi nozzle structure and multi nozzle linkage.

2、 SMT Mounter industrial computer and information processing technology

Due to the strict real-time requirements of the industrial computer system, SMT equipment needs to have the ability of multi task synchronous processing, such as online programming, multi task interface and real-time work. Therefore, it is necessary to build a real-time multitask control model for SMT devices, which runs on the real-time multitask operating system as the implementation platform of SMT control. Information processing includes information access, exchange, operation, judgment and decision-making. Computer is the main tool to realize information processing. Information processing technology and computer application are the most active factors to promote the development of SMT and mechatronics technology. SMT Mounter is controlled by computer. Generally, it adopts two-level computer control: each Mounter has its own set of control software to control the movement of mechanical structure; the main control computer uses software to realize programming and human-machine interface. With the rapid development of computer technology, windows operating system has completely replaced DOS, OS2 and other platforms, which makes the operation of Mounter more visual and intelligent. The intelligent level of SMT Mounter has been greatly improved.

3、 Visual inspection and sensor technology of SMT Mounter

The research direction of SMT placement machine vision detection and sensor technology is sensor and its signal detection device. It is of great significance to develop the mechatronics technology by vigorously developing the research of vision detection and sensor technology. Because machine vision has advanced nature in enhancing detectability and improving detection accuracy, machine vision has been widely applied in the field of SMT components and SMT product quality detection with the improvement of electromechanical automation technology. Nowadays, almost all high-precision Mounter systems have vision subsystem for positioning. Using these subsystems to detect and process the original position information of the target, we can get the feedback information needed by the computer, and provide accurate data for precise component mounting. Visual inspection technology can accurately locate and calibrate the components. Because of the higher and higher requirements of electronic components for mounting accuracy, the new full vision technology for surface mounting technology used in high-precision microelectronics equipment adopts high-precision and high-speed image processing and feature extraction methods. In addition, visual technology can also be used for image recognition of mounting IC, for component classification, waste disposal, etc., to improve mounting quality and efficiency. Machine vision detection technology includes: (1) high-speed image processing technology for patch; (2) high-speed machine vision recognition technology; (3) lighting technology, etc. Some advanced SMT machine vision uses flight detection technology to realize the location correction and defect detection of electronic components. This technology has the ability of real-time detection and positioning in the process of component pick-up, positioning and mounting, so that SMT Mounter can achieve the purpose of improving the mounting efficiency under the condition of ensuring the accuracy.

Mounting equipment needs high reliability and high precision electromechanical detection and positioning technology. In order to make SMT Mounter mechanism work together, mounter is installed with a variety of sensors, they are like the eyes of SMT Mounter, constantly monitoring the operation of the machine, and can effectively adjust the working state of SMT Mounter. The more sensors are used, the higher the intelligent level of SMT is. The main types of sensors used in SMT Mounter are position sensor, negative pressure sensor and pressure sensor. (1) Position sensor is to monitor the limit position of various motion positions; (2) the negative pressure sensor monitors the change of negative pressure. When the suction nozzle cannot absorb or hold the components, the negative pressure data is abnormal, and the sensor feeds the abnormal information back to the computer, and the system can give an alarm in time; (3) the pressure sensor is to let the mounting head mount the components on the circuit board The mounting force can be adjusted to avoid too much force damaging PCB or too little force not in place.

4、 Automatic control technology of SMT Mounter

Automation control technology has a wide range, including the whole process from theory to practice, such as automatic control theory, control system design, system simulation, field debugging, reliable operation, etc. Because of the wide application of microcomputers, automation control technology is more and more integrated with computer control technology, which has become a very important core technology in mechatronics. Automatic control technology is the core of the whole mounting equipment. Taking SMT Mounter as an example, because the mounting speed of components is affected by PCB size, components used and feeder type, various factors should be taken into account when selecting control technology, and the motion sequence and path of Mounter should be optimized to minimize the total travel time of the whole circuit board, so as to achieve the most efficient purpose. Due to the strict time requirements of SMT Mounter and the miniaturization of IC pin spacing, the positioning accuracy of IC on PCB should be kept within 0.1mm under the condition of high-speed movement (such as linear speed up to 100km / h, acceleration up to 5-6G), and the mounting strength of components should be strictly controlled at the same time, so the speed, acceleration, vibration, impact and mounting strength should be achieved In order to achieve high precision, high efficiency and high speed, SMT Mounter needs to establish motion control model and develop intelligent control strategy.