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The three main core equipment of SMT production line?
PCBA Tech
The three main core equipment of SMT production line?

The three main core equipment of SMT production line?

2021-11-07
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Author:Downs

SMT chip processing factory tells you which three main core equipment? The SMT production line mainly includes: three core production equipment-solder paste printer, placement machine, reflow soldering equipment, three auxiliary inspection equipment-SPI, AOI, X-Ray and rework workstations, etc.

SMT chip processing plant

These equipments involve technology: printing, mounting, welding technology, two-dimensional and three-dimensional optics, X-ray inspection technology, etc. The placement machine is the primary core equipment: it is used to achieve high-speed, high-precision, and fully automatic placement of components. It is related to the efficiency and accuracy of the SMT production line. It is a key and complex equipment, which usually accounts for 60% of the investment in the entire SMT production line. above.

The SMT workshop of the electronics factory introduces a full set of automation solutions to reduce manual participation and improve product quality and consistency.

Solder paste printing in SMT process is very important to quality and efficiency!

SMT mass production SMT bottlenecks mainly come from the solder paste printing process; in order to reduce labor costs and pursue personal output value: In mass production, SMT placement machines popularize dual-track and single-plate PCB production rhythms.

pcb board

The proportion of dual-track PCB in and out time when CT=10Sec Close to 0, auxiliary waste is 0, personal output is maximized; Printer CoreCT10Sec or less and dual tracks are inevitably required.

At present, the Chip components selected for electronic products tend to be miniaturized and thinner, and the chip wiring pitch and solder ball diameter have been reduced, which puts forward higher requirements for the alignment and positioning accuracy of placement equipment. At present, the challenges brought by high-density placement accuracy of high-end multi-function placement machines include:

One is to improve the parts supply department of the placement machine, including the improvement of the position accuracy of the parts supply, the tape accuracy, and the packaging accuracy of the parts themselves;

2. The high rigidity of the shaft that determines the suction position of the part and the high precision of the drive system improve the ability of the position recognition system before the part is placed;

Third, the placement machine will not generate excess vibration during the placement process, and it has strong adaptability to external vibration and temperature changes; fourth is to strengthen the automatic calibration function of the placement machine. Most of the modern placement machines are developing in the direction of combining high-speed and high-precision motion control and vision correction systems.

Due to the 75% defect rate of SMT production line in printing equipment, high-density placement accuracy will bring greater challenges to printing and testing equipment manufacturers:

1. It is to ensure that the process requirements (0.66 demoulding rate) will bring huge challenges to the thickness of the stencil and the amount of solder paste. At the same time, solder paste with a smaller powder diameter is required, which brings an increase in cost and a process problem of inhibiting oxidation. ;

2. The requirement of dust-free environment will increase the cost of exhaust system, air filtration system, auxiliary materials, anti-static floor, etc.;

Third, the balance between accuracy and speed of SPI and AOI equipment will face challenges.

In view of the development trend of SMT technology, comprehensively considering the flexible assembly and the bonding materials, printing, placement, and reflow when assembling very small parts, assembly equipment will face challenges in assembly quality, production efficiency, and assembly process.

SMT originated in the 1970s and entered a period of great development in the 1980s. It is widely used in aviation, aerospace, military, shipbuilding, household appliances, automobiles, machinery, instruments and many other fields. It is called "the third revolution of electronic production technology." ".

At present, SMT has entered a new stage of contemporary advanced electronic assembly technology marked by micro-assembly technology (MPT: Microelectronic Pakaging Technology), high-density assembly and three-dimensional assembly technology (3D: Three Dimensional), as well as multi-chip components (MCM: Multi Chip). Module), Ball Grid Array (BGA: Ball Grid Array), Chip Size Package (CSP: Chip Size Package) and other new surface mount components are in the rapid development and mass application stage.

The SMT assembly system develops and progresses with the development of SMT. Its development trend is mainly reflected in the continuous improvement of system performance, the continuous improvement of the ability to adapt to various new component assembly and lead-free soldering and other new assembly processes, as well as the diversification and diversification of system integration forms. The integration level continues to improve and so on.

With the miniaturization and multi-function of mobile electronic devices (such as smart phones and wearable devices), the components used are getting smaller and smaller, the structure is getting more and more complex, and the packaging density is getting higher and higher. Raises great challenges.

PoP and BGA have become the mainstream of packaging technology by virtue of their performance and price advantages. With the development of miniaturization and high density of electronic devices, the pitch and size of solder balls have become smaller and smaller, and the substrate has continued to be thinner, but the package size has continued to increase, the number of pins has continued to increase, and the complexity has also increased.

SMT is composed of surface mount components, circuit substrates, assembly design, assembly materials, assembly process, assembly equipment, assembly system control and management and other technologies. It is a project involving microelectronics, precision machinery, automatic control, welding, fine chemicals, materials Comprehensive engineering science and technology of multiple disciplines and multiple disciplines, such as, testing and so on.

The concept of SMT production line:

SMT surface assembly equipment mainly includes solder paste printers, dispensers, placement machines, reflow soldering furnaces, wave soldering furnaces, cleaning equipment, testing equipment, and rework equipment. Generally, SMT production line or production system is composed of main equipment such as solder paste printer, placement machine, and reflow oven.

The SMT solder paste printer is composed of a screen, a squeegee, and a printing workbench. After the stencil and the printed circuit board are positioned, apply pressure to the squeegee while moving the squeegee to roll the solder paste, filling the opening of the stencil with the solder paste. Furthermore, using the thixotropy and adhesion of the solder paste, the solder paste is transferred to the printed circuit board through the mesh.

Solder paste printing process steps:

Coating the solder paste on the stencil, the squeegee is traversed at a certain speed and pressure, the solder paste is squeezed into the opening of the stencil, and it is demolded on the PCB pads corresponding to the substrate.