China Topscom Delivered Speech About characteristics and technological process of Electronics contract Manufacturing Outsourcing Industry On 2019 CITE China Information Technology Expo Fair.
Keywords: pcba,pcb board,pcb assembly,electronic manufacturing,OEM EMS Market,smt mainland company,oem manufacturing, pcb smt assembl
1. Technical level and technical characteristics of the industry.
SMT (Surfaced Mounting Technology), is the most popular technology and process in the electronic assembly industry at present. It is a kind of pcb circuit assembly technology which installs non-lead or short-lead surface assembly components (also called sheet components) on the surface of printed circuit board or other substrate and assembles them by means of reflow soldering or wave soldering. It is mainly used for the assembly of electronic components. The wide application of SMT is mainly based on the pursuit of miniaturization of electronic products, and the original parts of punched plug-ins used in the past can not be reduced; the functions of electronic products are more complete, and the IC used has no perforated original parts, especially large-scale, highly integrated IC, has to use surface patch components.
As a new generation of electronic assembly technology, SMT has brought about fundamental and revolutionary changes in electronic assembly technology with its own characteristics and advantages. At present, SMT has been widely used in various fields of electronic assembly, and has completely replaced the traditional electronic assembly technology in many fields, and in the process of application, SMT assembly itself is constantly developing and improving. the article is posted by Dr.Chai Lianxing,vice president of Topscom,china Topscom provide high difficulty density & printed circuit boards PCB design & layout, mass manufacturing & fabrication,pcba boards assembly,turnkey full systems integration electronic contract manufacturing services.
(1) SMT has become an efficient and agile technical equipment.
At present, the technology and equipment of SMT pipes is developing in the direction of agility, flexibility and rapid response. The high production efficiency of the SMT production line is mainly reflected in the capacity efficiency and control efficiency of the SMT production line, that is, with the support of the computational data network, the intelligent control mode is adopted to optimize the design parameters, control process and mounting mode, so that the mode and parameters can be converted accurately and effectively, so as to realize defect-free production.
(2) the development of SMT equipment.
The update and development of SMT equipment in surface mount technology represents the level of surface mount technology. At present, SMT equipment is developing to the direction of high performance by changing its structure. In order to improve the production efficiency and reduce the volume of the equipment, the SMT equipment is developing from the traditional single-channel printed circuit board (PCB) conveying to the dual-channel PCB conveying structure, and the mounting head structure is developing from the traditional single-head structure to the multi-head structure and multi-head linkage.
(3) the SMT production line is developing in the direction of green and environmental protection.
"Green production line" will be the development direction of SMT brands. That is to say, in the planning period, the environmental protection requirements should be considered from the aspects of SMT building line design, SMT equipment selection, process material selection, environment and logistics management, process waste treatment and process management of the whole line, and formulate corresponding process specifications in the production process to maintain and manage the SMT production line in a realistic, scientific and reasonable way to meet the needs of production and the requirements of environmental protection.
2. Industrial process flow.
The main production processes and processes of SMT are as follows:
Printing (solder paste)-- > testing (optional AOI automatic or visual inspection)-- > mounting (first sticking small devices followed by large devices: sub-high-speed patch and integrated circuit mount)-- > testing (optional AOI optical / visual inspection)-- > soldering (using hot air reflow soldering)-- > testing (AOI optical inspection appearance and functional testing)-- > maintenance (. Use tools: welding table and hot air unsoldering table, etc.)-- > split board (cutting board by hand or by sub-board machine).
The above process is simplified as follows: printing-- > patch-- > welding-- > maintenance. Testing links are added to each process to control the quality.
(1) Tin paste printing.
Its function is to leak the solder paste to the pad of PCB at an angle of 45 degrees with a scraper to prepare for the welding of components. The equipment used is the printing press (solder paste printing press), which is located at the front end of the SMT production line.
(2) parts mounting.
Its function is to accurately install the surface mount components to the fixed position of the PCB. The equipment used is the placement machine, which is located at the back of the printing press in the SMT production line. It is generally used in combination with high-speed machines and general-purpose machines according to production requirements.
(3) reflow soldering.
Its function is to melt the solder paste so that the surface mount components and PCB are firmly welded together. The equipment used is the reflow furnace, which is located behind the placement machine in the SMT production line. The temperature requirement is very strict, and the temperature measurement needs to be carried out in real time.
(4) AOI optical detection.
Its function is to check the welding quality of the welded PCB. The equipment used is the (AOI), position of the automatic optical testing machine. According to the needs of the detection, it can be configured in the appropriate place of the production line. Some are before reflow soldering and some are after reflow soldering.
Its function is to repair the PCB board that has been detected to be faulty. The tools used are iron burning, repair workstation, etc. Configured after AOI optical detection.
Its function is to split the multi-connected plate PCBA into separate individuals, generally using V-cut and machine cutting methods.