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SMT processing equipment and inspection items
PCBA Tech
SMT processing equipment and inspection items

SMT processing equipment and inspection items

2021-11-09
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Author:Downs

SMT production and processing equipment is a special equipment for SMT production line, which is used in the electronic processing and manufacturing industry. There are many SMT processing equipment. The most important SMT equipment is placement machine, solder paste printing machine, reflow soldering, AOI, board feeder, Connecting station, etc. Each machine equipment has a designated function and purpose. Let's talk about all kinds of SMT processing equipment.

1. SMT placement machine

SMT mounters can be divided into three types: turret mounter, arch mounter, and modular mounter.

The placement machine is the core of the SMT production technology. Its main function is to use the specified method to accurately and quickly place the electronic components of the package on the matching position of the PCB. It comprehensively adopts high-tech technologies such as light, electricity, and gas, and is a leader in high-precision mechatronics machinery and equipment.

pcb board

2. SMT processing printing machine

SMT processing printing machines mainly include three types: manual printing machines, semi-automatic printing machines, and fully automatic printing machines.

The printing machine is the starting position of the SMT production line and the leader of the quality and efficiency of the SMT section of the electronic digital product assembly. It mainly uses steel mesh to evenly coat the tin material on the matching pads of the PCB. Its working principle is similar to that of the school printing ink test paper. As the requirements for the production and assembly of electronic digital products are getting higher and higher, most companies use fully automatic printing equipment.

3. SMT processing reflow furnace

The reflow furnace is the guarantee of the quality of the surface assembly of electronic digital products. It mainly uses the form of hot air convection to continuously heat the unsoldered PCB to melt and cool the soldering material, and solidify the components and the PCB pads into one.

4. AOI machinery and equipment

AOI is an efficient quality inspection equipment in the electronic and digital product assembly industry. It uses image contrast to quickly and accurately detect various types of defects generated in each production process section.

What are the inspection items before smt patch processing?

1. Inspection of components before smt chip processing: The main inspection items of components include: solderability, pin coplanarity and usability, which should be sampled by the inspection department. To test the solderability of components, stainless steel tweezers can hold the component body and immerse it in a tin pot at 235±5℃ or 230±5℃, and take it out at 2±0.2s or 3±0.5s. Check the soldering end of the solder under a 20 times microscope, and it is required that more than 90% of the soldering end of the component is soldered. The smt patch processing workshop can do the following visual inspections: 1. Visually or with a magnifying glass, check whether the solder ends or pin surfaces of the components are oxidized or have no contaminants. 2. The nominal value, specification, model, accuracy, and external dimensions of the components should be consistent with the product process requirements. 3. The pins of SOT and SOIC cannot be deformed. For multi-lead QFP devices with a lead pitch of less than 0.65mm, the pin coplanarity should be less than 0.1mm (optical inspection by the placement machine). 4. For products that require cleaning before smt chip processing, the marks of the components will not fall off after cleaning, and will not affect the performance and reliability of the components (visual inspection after cleaning). 2. Printed circuit board (PCB) inspection before smt chip processing (1) PCB land pattern and size, solder mask, silk screen, and via hole settings should meet the design requirements of smt printed circuit board. (Example: Check whether the pad spacing is reasonable, whether the screen is printed on the pad, whether the via is made on the pad, etc.). (2) The external dimensions of the PCB should be consistent, and the external dimensions, positioning holes, and reference marks of the PCB should meet the requirements of the production line equipment.