SMT chip processing has certain requirements on the environment, humidity and temperature. In order to ensure the quality of electronic components and enable the processing quantity to be completed in advance, the working environment has the following requirements:

The first is the temperature requirement. The best temperature in the plant is 23±3℃ throughout the year, and cannot exceed the limit temperature of 15～35℃.

The second is the humidity requirement. The humidity of the SMT processing workshop has a great influence on the quality of the product. The higher the environmental humidity, the electronic components are easily damp, which affects the electrical conductivity. The welding is not smooth, and the humidity is too low. The air is easy to dry, and it is easy to generate static electricity. Therefore, when entering the SMT patch processing SMT patch processing workshop, the processing personnel also need to wear anti-static clothing. Under normal circumstances, the workshop is required to maintain a constant humidity around 45%～70%RH

The other is the cleanliness requirements. The workshop must be free of any odor and dust, and keep the interior clean and free of corrosive materials. They will seriously affect the reliability of capacitor resistors and increase the cost of SMT chip processing equipment. The failure repair rate reduces the production schedule. The best cleanliness of the workshop is about 100,000 (BGJ73-84).

Finally, there are requirements for the stability of the power supply. In order to avoid equipment failure during processing, which affects the processing quality and progress, it is necessary to add a voltage regulator to the power supply to ensure the stability of the power supply.

SMT patch inspection items are as follows:

1. Tin ball: The solder ball violates the small electrical clearance. The solder balls are not fixed in the clean-up residue or covered under the conformal coating. The solder ball diameter ≤0.13mm can be accepted, otherwise, it is rejected.

2. False welding: The stacking part (J) between the solderable end of the component and the PAD is clearly visible. (Accepted) The stack between the end of the component and the PAD is partially lacking (rejected)

3. Side standing: The ratio of width (W) to height (H) does not exceed two to one (allowable), and the ratio of width (W) to height (H) exceeds two to one (see the left picture). The solderable end of the component and the surface of the PAD are not completely wetted. Components are greater than 1206 categories. (Reject)

4. Tombstone: the end of the chip component is raised (tombstone) (rejected)