Preface

 

 

 

The placement machine is a piece of equipment with a high technical content in electronic assembly equipment. It involves material forming and processing, mechanical transmission, motor and servo drive, laser, and visual images in the fields of mechanics, optics, electronics, materials, mechanics, automation, and computers. The integration of various series of technologies such as , pneumatics, sensors, automatic control and computer software/hardware is one of the main indicators of the development level of electronic manufacturing equipment. Since the advent of the chip placement machine, the technology has been continuously updated, the functions have been continuously enhanced, the performance indicators have been continuously improved, and the level of automation and intelligence has been continuously improved, adapting to the development trend of micro-miniaturization, multi-function and low cost of electronic information products. There are dozens of famous manufacturers in the world producing more than 100 types of placement machines.

 

 

 

With the trend of diversification and personalization of electronic products, electronic components are becoming increasingly miniaturized. There are more and more pins on electronic devices, the spacing is getting finer, and the mounting positions are getting closer and closer. The high precision and high speed of the placement machine and flexibility are constantly developing. Although the variety and variety of placement machines are dazzling, the basic functions and working principles of placement machines have not fundamentally changed. The basic composition and technical principles of various placement machines are the same.

 

 

 

With the development of the electronic industry, electronic components are becoming more and more precise and diverse. Currently, chip components have developed from 0402 (metric system is 1005) to 0201 (metric system is 0603) and 01005 (metric system is 0402), plus such as BGA , CSP/μBGA, FC and MCM and other packaged components have emerged and been widely used. Objectively, they have put forward higher requirements for patch equipment, and the requirements for assembly efficiency are also getting higher and higher. As the main equipment for electronic assembly, the placement machine must become more and more precise and high-speed with the development trend of the electronics industry. The placement machine is a key equipment in the integrated circuit board (PCB) assembly production line. It can attach components (common ones such as chip capacitors, chip resistors and chip chips, etc.) to designated positions on the integrated circuit board at high speed and with high precision. , and conduct quality inspection and identification of components before placement. The placement machine is a highly automated equipment that integrates precision machinery, automatic control and computer systems. It is mainly composed of a frame and transmission system, computer and hardware control system, servo and drive system, as well as software system and feeding system. Each system The details will be fully introduced later, so please pay attention to the official account and pay attention to the follow-up content.

 

 

 

1. Composition of placement machine

 

 

 

The placement machine is actually a sophisticated industrial robot, which is a combination of mechanical-electro-optical and computer control technology.

 

 

 

1) Basic composition

 

 

 

Fundamentally speaking, the placement machine is composed of software and hardware: the hardware part includes mechanical mechanisms (including the mechanical body, transmission and drive mechanisms, pneumatic vacuum systems and other mechanical mechanisms), optical systems (including vision systems, light sources and control etc.) and electronic circuits and computers (including sensor circuits, image processing, various electronic control circuits and industrial computer systems); the software part includes three parts: operating system software, machine control software and system management software, as shown below shown

 

 

 

 

 

2.) Hardware structure

 

 

 

Although there are many types of placement machines, the basic functions and requirements are the same, that is, they are required to be able to place components (common ones such as chip capacitors, chip resistors and IC chips, etc.) on printed circuit boards at high speed and with high precision. designated position, so the basic structure consists of three major mechanisms (PCB transfer mechanism, feeding mechanism and placement mechanism) and the main body of the machine, as shown in the figure below.

 

 

 

 

 

3)  Functional structure

 

 

 

According to the functions of each part of the placement machine, the entire system can be divided into three major parts: mechanical system, control system and visual system, as shown in the figure below.

 

 

 

 

 

2. Key technologies of placement machines

 

 

 

1) Precision machine photoelectric integration technology

 

 

 

The placement machine is a precision electromechanical device that relies on mechanical motion to grab components from the feeder and place them on the circuit board after being centered by a calibration mechanism. Due to the miniaturization and diversification of mounted components and the speed and accuracy requirements of assembly technology, a variety of precise and complex mechatronics technologies must be adopted to achieve machine function and performance requirements. These technologies include 3 major parts: motion and actuator and related technologies, including high-precision dedicated pick/place mechanisms to achieve micro-assembly; new motion mechanisms to solve the contradiction between large movement space and small occupied volume; macro/micro drive Ability detection theoretical methods and related technologies. The specific technologies are as follows:

 

 

 

• Design, manufacturing and assembly technology of precision, miniaturized and highly reliable mechanical parts;

 

 

 

• High-efficiency, low-loss, fast-response, and precision micro-positioning mechanism composite transmission technology for motion machinery;

 

 

 

• High-precision, high-reliability electromechanical detection and positioning technology;

 

 

 

• Linear motor drive technology;

 

 

 

• Fast, accurate and reliable conveying and positioning technology for single/dual channel printed circuit boards;

 

 

 

• Highly reliable vacuum and pneumatic technology;

 

 

 

• Intelligent high-precision and high-speed placement head technology.

 

 

 

2.) Machine vision and image recognition processing technology

 

 

 

Due to the unique advantages of optical systems in improving detection accuracy and enhancing detectability, and with the improvement of automation technology, laser and machine vision are now widely used in placement machine technology, especially machine vision technology. The role of installation technology is becoming more and more important. The fine pitch of QFP pins in 0201, 01005 components and IC packages, as well as the application of BGA, CSP, COB, FlipChip and MCM, have further increased the requirements for placement accuracy, and the requirements for visual and image recognition technology are also getting higher and higher. Modern vision and image recognition technologies in placement machines mainly include:

 

 

 

• Dual camera application - a fast camera for small components and a high-resolution camera for larger IC circuits in one placement unit, each performing its own duties to maximize efficiency;

 

 

 

• Downward-looking and upward-looking cameras—solve printed circuit board benchmarks and component calibration respectively;

 

 

 

• Flight alignment technology – increases machine speed;

 

 

 

• High-efficiency, multi-spectral light source lighting technology;

 

 

 

• High-speed and efficient image acquisition, transmission, and processing technologies, especially the application of image processing "hardware accelerators" that have emerged in recent years - Graphic Processing Unit (GPU) in industrial computers, make image processing faster and more efficient It has been greatly improved. At the same time, in some calculations such as floating point operations and parallel computing, the GPU can provide dozens or even hundreds of times the performance of the CPU, providing strong support for the machine vision and image recognition processing technology of the placement machine.

 

 

 

3. Intelligent precision control technology

 

 

 

Control technology is the core of the entire placement machine. Since the placement speed of components is affected by the size of the circuit board, the components used and the type of feeder, etc., the control technology used should take various factors into consideration and optimize the movement of the placement head so that it can move along the entire circuit board. The travel time is kept to a minimum to achieve the optimal purpose.

 

 

 

Due to the mounting speed requirements of surface mount equipment and the miniaturization of component pin spacing, if the linear speed exceeds 100mm/s, the acceleration can reach up to 5 to 6 g, and the positioning accuracy needs to be maintained within 0.1mm. At the same time, the component The placement force also needs to be strictly controlled. The main control technologies of the placement machine are:

 

 

 

• Fast and precise control of PCB transmission and positioning;

 

 

 

• The X/Y motion mechanism is highly efficient, high-speed, vibration-damping, highly reliable and precisely controlled;

 

 

 

• Intelligent control of complex movements of the placement head system;

 

 

 

• Precise control of Z-axis movement and placement force;

 

 

 

• Intelligent high-speed motion precision control technology;

 

 

 

• Optimization control strategy for the entire picking/detection/mounting process;

 

 

 

• Dynamic error control technology;

 

 

 

• High-speed, efficient and optimal control of modular placement machines.

 

 

 

4) Modularization and system integration technology

 

 

 

As an electromechanical device that mainly uses mechanical motion to complete the placement function, the most effective solution for improving the three basic requirements of speed, accuracy and flexibility is modularization and system integration technology. Flexible modular technology emphasizes the portability, interoperability, scalability and configurability of equipment, and provides the equipment control platform with reconfigurability and openness to control requirements, so that it can construct and complete specific requirements simply and efficiently. Surface mount equipment to improve assembly productivity.

 

 

 

The main technical features of modularization and system integration technology are:

 

 

 

• Efficient, flexible and scalable modular structure;

 

 

 

• Modular application management system;

 

 

 

• Safe, reliable, and complete device interfaces and communication protocols;

 

 

 

• Surface mount production line system optimization and integration technology.

 

 

 

5) Efficient and intelligent software technology

 

 

 

As the composition and structure of placement machines become increasingly complex and diversified, the importance of placement machine software technology is increasingly reflected. In particular, the speed of upgrading of contemporary products is accelerating. Under the situation where flexible production has become an inevitable trend, efficient and intelligent software plays a key role in the performance of equipment functions and efficiency.

 

 

 

The efficient and intelligent software for the placement machine mainly includes:

 

 

 

• Efficient real-time multi-tasking parallel processing operating system;

 

 

 

• Convert product design files into placement machine programs;

 

 

 

• Intelligent placement program optimization;

 

 

 

• SMT management and automatic fault diagnosis system;

 

 

 

• Integrated management system for assembly production optimization.