Carrier type
The carrier tape is produced according to EIA 481e standard and used in conjunction with the cover tape (upper sealing tape, also known as cover tape). The carrier tape stores electronic components such as patch resistor, patch capacitor, patch MOS tube and patch diode in the pocket, and seals the cover tape above to form a closed package. In this way, electronic components will not be polluted and damaged during transportation.
During SMT assembly, the cover tape is stripped, and the automatic mounting equipment takes out the electronic components placed in the pocket in turn through the accurate positioning of the tape index hole, feeds them to the mounter, and assembles them on the PCB through SMT technology.
According to the different packaging of electronic components, there are many kinds of carrier tapes
Although the carrier belt is only an auxiliary material, it has a variety of types.
According to different widths, common widths include 8mm, 12mm, 16mm, 24mm, 32mm, 44m, 56mm, etc. According to the size of the electronic components, the user selects the belt products with suitable width.
According to different materials, the carrier belt mainly includes two types: plastic (polymer) and paper. Embossed carrier tape is mainly composed of plastic materials. The mainstream in the market are polycarbonate (PC) carrier tape, polystyrene (PS) and ABS (acrylonitrile butadiene styrene copolymer resin) carrier tape. Among them,
(1) PC material is characterized by high mechanical strength, good transparency, good dimensional stability, high glass transition temperature and good heat resistance.
(2) The mechanical strength of PS material is lower than that of PC material, so sometimes it will be made into three-layer composite sheet with ABS material to improve the tensile strength of the carrier belt. The mechanical strength of PET material is close to that of PC, but it is crystalline material with poor dimensional stability.
In addition, there are also a small amount of carrier tapes prepared from pet, APET and other materials. The stamping carrier belt is mainly made of paper material or PE composite material.
Process characteristics
Although the carrier belt is only an auxiliary material, its functions are different according to the production process and processing mode. In the application, the user carries the product characteristics and service conditions. Some basic considerations are as follows.
According to the pocket forming process, the carrier belt can be divided into intermittent (plate molding) and continuous (roller rotating) forming methods. Among them, the batch forming method is suitable for preparing large pockets. Relatively speaking, the continuous forming method has better dimensional stability and higher dimensional accuracy.
8, 12, 1, 24mm wide carrier tape and requirements for MLCC chip capacitor packaging
8, 12, 1, 24mm wide carrier tape and requirements for MLCC chip capacitor packaging
There are two kinds of pockets: embossed carrier tape and punched carrier tape. Embossed carrier belt refers to a pocket with concave shape formed by stretching the local part of the carrier belt material through die embossing or blistering. This carrier belt can form pockets of different sizes according to specific needs to adapt to the size of electronic components; Stamping carrier belt refers to forming penetrating or semi penetrating pockets through die punching. The thickness of electronic components that can be contained by this carrier belt is limited by the thickness of the carrier belt itself, and generally can only be used to package smaller components.
In terms of antistatic performance, the carrier tape can be divided into three types: conductive type, antistatic type (electrostatic dissipation type) and insulating type. Semiconductor products, especially integrated circuit packaging, are particularly sensitive to static electricity. Their conveying materials and packaging equipment must have anti-static measures. Precision electronic components have clear requirements for the anti-static level of the carrier belt. As for insulated carrier tape, it is generally used for non sensitive components such as connectors, FPC, shrapnel, nuts and so on.
Development trend
As an auxiliary material, the development of carrier products goes hand in hand with SMT and electronic components. In order to meet the needs of high-speed and reliable assembly of special components, some materials with high transparency, high brightness and high conductivity have been developed. The size and shape of matching components, the width and thickness of selected materials can also be customized.
In order to adapt to the miniaturization development trend of electronic components such as semiconductor chips, the carrier belt is also developing in the direction of small and precision. At present, the carrier belt with 4mm width has been supplied in the market.
