Professional testing organization: introduction to packaging methods of surface assembled components

Date：2021-12-31 15:44:40Views：921

Most commonly used components are first packaged, then packaged, and then shipped to customers. The packaging method of surface assembled components has become an important link in SMT system. It directly affects the efficiency of assembly and production. It must be optimized in combination with the type and number of feeders of mounter. This paper has collected and sorted out some materials, and I hope this paper can be of great reference value to all readers.

Packaging of surface assembled componentsBulk, disk braided packaging, tubular packagingandTrayThere are four types of packaging.

1. Bulk

SMC components without lead and polarity can be in bulk, such as general rectangular and cylindrical capacitors and resistors. The cost of bulk components is low, but it is not conducive to the picking and mounting of automatic equipment.

2. Disc braided packaging

Tape braiding packaging is applicable to other components except large-size QFP, PCC and LCCC chips. Its specific forms include paper tape braiding, plastic tape braiding and adhesive tape braiding.

Paper tape. The paper braiding belt is composed of a bottom belt, a carrier belt, a cover belt and a paper winding tray (belt tray). The circular small hole on the carrier belt is a positioning hole for driving the gear on the feeder; The rectangular hole is the material bearing cavity, which is used to place components. When packaging components with paper braided tape, the thickness of components shall be similar to that of paper tape. Paper braided tape shall not be too thick, otherwise the feeder cannot be driven. Therefore, paper braided tape is mainly used to package sheet resistors and sheet capacitors below 0805 specification (including) (with a few exceptions). The paper tape is generally 8mm wide. After packaging the components, it is wound on the plastic paper tray.

Plastic braid. The structural dimensions of plastic tape braiding and paper tape braiding are roughly the same, except that the material box is convex, and there are many kinds of components packaged with plastic tape braiding, including various leadless components, composite components, special-shaped components, sot transistors, SOP / QFP integrated circuits with few leads, etc. When pasting, the upper film stripping device on the feeder removes the film cover belt before reclaiming.

One side of the paper braided tape and the plastic braided tape is provided with a row of positioning holes for guiding the paper tape forward and positioning when picking up components. The hole spacing of positioning holes is 4mm (the braiding hole spacing of components less than 0402 series is 2mm). The distance between components on the tape depends on the length of components, which is generally a multiple of 4mm. The material tray for tape packaging is made of polystyrene (PS) material and consists of 1 ~ 3 parts. Its color is blue, black, white or transparent, which can usually be recycled.

Adhesive braiding. The bottom surface of adhesive tape braiding is adhesive tape, IC is pasted on the adhesive tape, and it is double row drive. When pasting, there is a lower stripping device on the feeder. Adhesive braiding is mainly used to pack chip components with large size, such as SOP, chip resistance network, delay line, etc.

3. Tubular packaging

Tubular packaging is mainly used for SOP, SOJ, PLCC integrated circuits, PLCC sockets and special-shaped components. From the production type of the whole machine, tubular packaging is suitable for products with many varieties and small batches. The packaging tube (also known as material strip) is composed of transparent or translucent polyvinyl chloride (PVC) materials, extruded into a standard shape that meets the requirements. The number of parts per tube of tubular packaging varies from dozens to nearly 100. The direction of components in the tube is consistent and cannot be installed reversely.

4. Pallet packaging

The tray is made of carbon powder or fiber material. Generally, the component tray exposed to high temperature is required to have temperature resistance of 150 ℃ or higher. The tray is cast into a rectangular standard shape, including a unified alternating cavity matrix, which supports the components and provides protection for the components during transportation and processing. The spacing provides accurate component positions for standard industrial automation equipment used for mounting during circuit board assembly. The components are arranged in the tray. The standard direction is to place the first pin in the beveled corner of the tray. Tray packaging is mainly used for QFP, narrow spacing SOP, PLCC, BCA integrated circuits and other devices.

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