PCB Technical - ​What is the SMT chip processing technology?

SMT patch processing overview:

SMT patch refers to PCB (PrintedCircuitBoard) for a series of technological processes that are processed on the basis of PCB. The Chinese name is printed circuit board, also known as printed circuit board, printed circuit board. It is an important electronic component and an electronic element. The support of the device is the provider of the electrical connection of the electronic components. Because it is made by electronic printing, it is called a "printed" circuit board.

Mounter

SMT is the surface mount technology (Surface Mounted Technology) (abbreviation of Surface Mounted Technology), which is currently the most popular technology and process in the electronics assembly industry. Electronic circuit surface mount technology (Surface Mount Technology, SMT) is called surface mount or surface mount technology. It is a kind of surface assembly components with no leads or short leads (SMC/SMD for short, chip components in Chinese) mounted on the surface of a printed circuit board (Printed Circuit Board, PCB) or the surface of other substrates. Circuit assembly technology in which reflow soldering or dip soldering is used for soldering and assembling.

Under normal circumstances, the electronic products we use are designed by PCB plus various capacitors, resistors and other electronic components according to the designed circuit diagram, so all kinds of electrical appliances need a variety of smt chip processing techniques to process.

SMT basic process components: Solder paste printing -> parts placement -> reflow soldering -> AOI optical inspection -> maintenance -> sub-board.

Some people may ask why it is so complicated to connect an electronic component? This is really closely related to the development of our electronics industry. Nowadays, electronic products are pursuing miniaturization, and the perforated plug-ins used before The component cannot be reduced. Electronic products have more complete functions, and the integrated circuits (ICs) used have no perforated components, especially large-scale, highly integrated ICs, and surface mount components have to be used. With mass production of products and automation of production, the factory must produce high-quality products with low cost and high output to meet customer needs and strengthen market competitiveness. The development of electronic components, the development of integrated circuits (IC), and the diversified application of semiconductor materials. The revolution of electronic technology is imperative and chasing the international trend. It is conceivable that in the case of intel, amd and other international cpu and image processing device manufacturers whose production process has advanced to more than 20 nanometers, the development of smt, such as surface assembly technology and process, is also not a case of it.

The advantages of smt patch processing: high assembly density, small size and light weight of electronic products. The volume and weight of patch components are only about 1/10 of that of traditional plug-in components. Generally, after SMT is adopted, the volume of electronic products is reduced by 40%~60 %, the weight is reduced by 60%~80%. High reliability and strong anti-vibration ability. The defect rate of solder joints is low. Good high frequency characteristics. Reduce electromagnetic and radio frequency interference. It is easy to realize automation and improve production efficiency. Reduce costs by 30%~50%. Save materials, energy, equipment, manpower, time, etc.

It is precisely because of the complexity of the process flow of smt patch processing that many smt patch processing factories have emerged, specializing in smt patch processing. In Shenzhen, thanks to the vigorous development of the electronics industry, smt patch Processing has contributed to the prosperity of an industry.

SMT patch processing process:

Single-sided assembly:

Incoming inspection + silk screen + solder paste (red glue) + patch + reflow (curing) + cleaning + inspection + repair

Single-sided mixed installation:

Incoming inspection + PCB A side silk screen solder paste (red glue) + SMD + A side reflow (curing) + cleaning + plug-in + wave crest + cleaning + inspection + repair

Double-sided assembly:

Incoming inspection + PCB's A side silk screen solder paste (red glue) + patch + A side reflow (curing) + cleaning + flip board + B side silk screen solder paste (red glue) + patch + B side reflow (curing) Or (DIP + wave crest) + cleaning + inspection + repair

Double-sided mixed:

Incoming inspection + PCB's B side silk screen solder paste (red glue) + patch + B side reflow (curing) + cleaning + flip board + A side silk screen solder paste (red glue) + patch + B side reflow (curing) Or (DIP + wave crest) + cleaning + inspection + repair

The basic process components of SMT include: screen printing (or dispensing), placement (curing), reflow soldering, cleaning, inspection, and repair

Silkscreen:

Its function is to print solder paste or patch glue onto the PCB pads to prepare for the soldering of components. The equipment used is a screen printing machine (screen printing machine), located at the forefront of the SMT production line.

Dispensing:

It drops glue onto the fixed position of the PCB, and its main function is to fix the components on the PCB. The equipment used is a dispenser, located at the forefront of the SMT production line or behind the testing equipment.

Mounting:

Its function is to correctly install the surface mount components to the fixed position of the PCB. The equipment used is a placement machine, located behind the screen printing machine in the SMT production line.

Curing:

Its function is to melt the patch glue, so that the surface mount components and the PCB board are firmly bonded together. The equipment used is a curing oven, located behind the placement machine in the SMT production line.

Reflow soldering:

Its function is to melt the solder paste, so that the surface mount components and the PCB board are firmly bonded together. The equipment used is a reflow oven, located behind the placement machine in the SMT production line.

Cleaning:

Its function is to remove the solder residues such as flux that are harmful to the human body on the assembled PCB board. The equipment used is a washing machine, and the location may not be fixed, it may be online or offline.

Detection:

Its function is to inspect the welding quality and assembly quality of the assembled PCB board. The equipment used includes magnifying glass, microscope, online tester (ICT), flying probe tester, automatic optical inspection (AOI), X-RAY inspection system, functional tester, etc. The location can be configured in a suitable place on the production line according to the needs of testing.

Rework:

Its function is to rework the PCB boards that have detected faults. The tools used are soldering irons, rework stations, etc. Configured at any position in the production line.

The specifications of the processed components are: LGA, CSP, BGA, QFP, TQFP, QFN, PLCC, SOT, SOIC, 1206, 0805, 0603, 0402, 0201.

Processing mode: PCB welding processing, lead-free SMT chip processing, plug-in processing, SMD chip, BGA soldering, BGA ball planting, BGA processing, chip packaging.

Processing includes: mobile phone boards, automobile testing equipment, B-ultrasound machines, set-top boxes, routers, network players, driving recorders, PLCs, display controllers, spectrum analyzers, hairdressers and other products;

The main SMT chip processing materials and processes include: SMT processing of ordinary circuit boards (hard boards) and flexible circuit boards (soft boards). The processing technologies are: solder paste process, red glue process, red glue + solder paste dual process, among which The dual process of red glue + solder paste effectively eliminates the problem of easy parts dropout in a single red glue process.