What are the general requirements for PCBA outsourcing?

For some PCBA processing factories, during the industry boom at the end of September to December, many PCBA processing orders will be accepted. Therefore, many PCBA processing manufacturers will conduct PCBA outsourced processing when they cannot normally schedule production. PCBA outsourcing processing refers to the outsourcing of PCBA orders by PCBA processing manufacturers to other capable PCBA processing manufacturers. So, what are the general requirements for PCBA outsourcing?

I. Bill of Materials

Components should be inserted or placed in strict accordance with the bill of materials, PCB silkscreen and outsourcing processing requirements. When materials do not conform to the bill of materials, PCB silkscreen, or conflict with process requirements, or the requirements are ambiguous and cannot be operated, it should be timely Contact our company to confirm the correctness of material and process requirements.

Second, anti-static requirements

1. All components are treated as static sensitive devices.

2. All persons who come into contact with components and products should wear antistatic clothing, antistatic bracelets, and antistatic shoes.

3. At the stage of raw materials entering the factory and storage, the electrostatic sensitive devices are all packed with anti-static.

4. During the operation, use an antistatic work surface, and components and semi-finished products should be stored in antistatic containers.

5. The welding equipment is reliably grounded, and the electric soldering iron is anti-static. They must be tested before use.

6, PCB board semi-finished products are stored and transported in anti-static boxes, and isolation materials are used in anti-static pearl cotton.

7. The whole machine without shell uses anti-static packaging bag.

3. Regulations on the direction of component appearance marking insertion

1. Polar components are inserted according to polarity.

2. When the components printed on the side (such as high-voltage ceramic capacitors) are vertically inserted, the silk screen is oriented to the right; when horizontally inserted, the silk screen is oriented downward. When the components printed on the top (not including the chip resistors) are inserted horizontally, the font direction is the same as that of the PCB screen printing; when vertically inserted, the upper part of the font faces right.

3. When the resistance is horizontally inserted, the error color ring is facing right; when the horizontal is vertically inserted, the error color ring is facing downward; when the resistance is vertically inserted, the error color ring is facing the board.

Fourth, welding requirements

1. The height of the pins of the plug-in components on the soldering surface is 1.5 to 2.0 mm. The patch components should be flat on the surface of the board, the solder joints should be smooth without burrs, and slightly arc-shaped, and the solder should exceed 2/3 of the height of the solder end, but should not exceed the height of the solder end. Less tin, solder balls are spherical, or solder covering patches are all bad;

2. Solder joint height: The height of the solder climbing lead pin is not less than 1mm on a single panel, and not less than 0.5mm on a double panel, and tin penetration is required.

3. Solder joint shape: it is conical and covers the entire pad.

4, solder joint surface: smooth, bright, no dark spots, flux and other debris, no spikes, pits, pores, exposed copper and other defects.

5, solder joint strength: fully wet with the pads and pins, no virtual soldering, false soldering.

6. Cross-section of solder joints: The component cutting feet should not be cut to the solder part as much as possible, and there is no cracking tin on the contact surface between the pin and the solder. No spikes or barbs on the cross section.

7. Needle seat welding: The needle seat requires the bottom board to be inserted, and the position is correct and the direction is correct. After the needle seat is welded, the bottom floating height does not exceed 0.5mm, and the seat body does not skew beyond the silk screen frame. The rows of needle seats should also be kept tidy, and no misalignment or unevenness is allowed.

V. Transportation

To prevent PCBA damage, the following packaging should be used during transportation:

1. Container: Anti-static turnover box.

2. Isolation material: anti-static pearl cotton.

3. Placement distance: There is a distance greater than 10mm between the PCB board and the board, and between the PCB board and the box.

4. Placement height: There is a space greater than 50mm from the top surface of the turnover box, to ensure that the turnover boxes are not pressed to the power supply, especially the power supply of the cable.

6. Washing requirements

The board surface should be clean and free of tin beads, component pins, and stains. In particular, the solder joints on the insert surface should not see any contamination left by welding. When washing the board, the following components should be protected: wires, connection terminals, relays, switches, polyester capacitors and other corrosive devices, and the relay must not be cleaned with ultrasonic waves.

Seven, after the installation of all components is not allowed to exceed the edge of the PCB board.

8. When the PCBA passes through the furnace, because the pins of the plug-in components are washed away by tin flow, some plug-in components will be tilted after being soldered, which will cause the component body to exceed the silk screen frame. Amended.