Introduction to PCB assembly

- Feb 16, 2017-

In today's rapid development, automotive electronics, industrial manufacturing, medical equipment and technology enterprises has been the trend of the development of intelligent, intelligent products for engineering research and development ability of the test to improve, there are very strict requirements on the manufacturing process, electronic circuit board and electronic products as essential, is an important component of the product operation the quality of the board will also affect the work efficiency of the product.

SMT is a surface mount technology, also known as surface mount technology (Surface Mounted Technology), is currently the most popular electronic assembly technology and technology.

SMT: Surface Mounted Technology (surface mount technology): the appearance of focal adhesion component mounting and assembly skills soldered to the circuit board PCB appearance rule orientation.

SMD:Surface Mounted Devices acronym, meaning: surface mount device, which is a component of SMT. There are many, such as sheet resistance, chip capacity, SMD transistor, SMD inductors, etc..

SMD is in the shape of rectangular shape, cylindrical shape or irregular, the welding end or pin manufacture in the same plane, Reflow soldering electronic components and is suitable for the appearance of adhesive (SMT reflow soldering): after melting AB pre assigned to PCB circuit board pads on the paste paste, between adhesive component of terminal or appearance the pin and the printed circuit board pads mechanical and electrical connection.

Chip: rectangular chip component (rectangular chip component): two leadless, welding end, shape of thin rectangular appearance of focal adhesion components.

SOP: Small Outline Package (small outline package IC): a small molded plastic package with a wing or J shape on both sides of a short pin assembly components.

QFP: Quad Flat Pack (quad flat package IC): four sides with a short wing pin, pin distance: 1.00,0.80,0.65,0.50,0.40,0.30mm and other SMT plastic packaging IC IC.

BGA: Ball grid array (ball grid array): package integrated circuit, the input and output is in the component on the bottom surface of the ball grid according to the display style.

SMT and SMD in the surface mount technology in the use of free cleaning process in the production process of cleaning products after the discharge of waste water, bring water quality, the earth so that the pollution of plants and animals. In addition to water cleaning, organic solvent using chlorine hydrogen fluoride (CFC&HCFC) for cleaning of air, the atmosphere pollution and damage. The corrosion of the cleaning agent on the board will seriously affect the quality of the goods. Reduce the cost of cleaning operation and machine protection. No cleaning can reduce the damage caused by the moving of the plate (PCBA) in the process of moving and cleaning. There are still some components can not be cleaned.

The flux residue has been controlled, can prevent the appearance of the commodity demand by cooperation, visually check the cleaning situation question. The residual flux has continuously improved its electrical function, to prevent product leakage, cause any damage. Disposable flow has been the international multiple safety test, proof of chemical SMT machine in the flux is stable, non corrosive.

BOM: Bill of materials (Bill of Material, BOM), use of computer-aided production management, first of all to make the computer can read the composition of products manufactured by enterprises and all materials to be involved in order to facilitate the computer identification, we must put the product structure by graphic expression into a data format, the data format to describe products the structure of the document is a list of materials, which is BOM which is the technical documents of product structure definition.

Therefore, it is also called product structure or product structure tree. In some industrial areas, may be referred to as "recipe", "factor table" or other name. In MRP II and ERP system, the material has a wide range of word meaning, it is all products, semi-finished products, products, raw materials, accessories, consumables and so on cooperation, and collectively involved in the production of materials.

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