PCBA Tech - Quality inspection of SMT patch processing products

Some introductions to the quality inspection points of SMT chip processing products:

The quality inspection points of SMT patch processing products

1. Quality requirements of component placement process

1. The components must be placed neatly, in the center, without offset or skew

2. The type and specification of the components in the mounting position should be correct; the components should be free of missing or wrong stickers

3. SMD components are not allowed to have reverse stickers

4. SMD devices with polarity requirements need to be installed according to the correct polarity markings

5. Component placement must be neat, centered, without offset or skew

2. Component soldering process requirements

1. The surface of the FPC board should be free of solder paste, foreign matter and stains that affect the appearance

2. The bonding position of the components should be free of rosin or flux and foreign matter that affect the appearance and soldering tin

3. The tin points under the components are well formed, and there is no abnormal wire drawing or sharpening

3. Appearance process requirements of components

1. There should be no cracks or cuts on the bottom, surface, copper foil, circuit, and through holes of the board, and no short circuit caused by poor cutting.

2. The FPC board is parallel to the plane, and the board has no convex deformation.

3. The FPC board should have no leakage V/V deviation

4. There is no blurring, offset, reverse printing, printing deviation, ghosting, etc. in the silk-screened characters of the marked information.

5. The outer surface of the FPC board should be free from swelling and blistering.

6. The aperture size requirements meet the design requirements.

Fourth, printing process quality requirements

1. The position of the solder paste is centered, there is no obvious deviation, and the paste and soldering should not be affected.

2. The printing tin paste is moderate, and it can be pasted well, and there is no little tin or too much tin paste.

3. The tin paste point is well formed, and should be free of tin and uneven.

SMT-related technical components

Design and manufacturing technology of electronic components and integrated circuits

The component feeder and the substrate (PCB) are fixed. The placement head (with multiple vacuum suction nozzles) moves back and forth between the feeder and the substrate, and the component is taken out of the feeder. After adjusting the position and direction of the component, Place it on the substrate. Since the placement head is installed on the arch-type X/Y coordinate moving beam, it is named after.

How to adjust the position and direction of the component:

1. The accuracy of mechanical alignment adjustment position and nozzle rotation adjustment direction is limited, and later models are no longer used.

2. Laser recognition, X/Y coordinate system adjustment position, nozzle rotation adjustment direction, this method can realize recognition during flight, but it cannot be used for ball grid array element BGA.

3. Camera recognition, X/Y coordinate system adjustment position, nozzle rotation adjustment direction, generally the camera is fixed, the smt patch head flies over the camera to perform imaging recognition, which takes a little longer than laser recognition, but it can recognize any component, and there are some The camera recognition system that realizes recognition during flight has other sacrifices in terms of mechanical structure.