PCBA outsourcing processing means that PCBA processing manufacturers send PCBA orders to other competent PCBA processing manufacturers.
PCBA outsourcing processing means that PCBA processing manufacturers send PCBA orders to other competent PCBA processing manufacturers.Then, what are the general requirements of PCBA outsourcing processing?
一. Bill of materials
The components shall be inserted or affixed in strict accordance with the bill of materials, PCB silk-screen and outsourcing processing requirements. In case of any discrepancy between the material and the list, PCB silk-screen, or contradiction with the process requirements, or if the requirements are ambiguous and cannot be operated, the components shall be timely contacted with our company to confirm the correctness of the materials and process requirements.
二. Anti-static requirements
1. All components are treated as electrostatic sensitive devices.
2. Wear anti-static clothes, anti-static bracelets and anti-static shoes for those who come into contact with components and products.
3. Anti-static packaging is adopted for electrostatic sensitive devices during raw materials entering the factory and storage.
4. During operation, use anti-static worktable, and use anti-static containers for components and semi-products.
5. Reliable grounding of welding equipment, and anti-static type of electric soldering iron.It should be tested before use.
6. Anti-static boxes are used for PCB semi-finished products storage and transportation, and anti-static pearl cotton is used for isolation materials.
7. Anti-static packaging bag is used for the whole machine without shell.
三. Provisions on insertion direction of appearance marks of components
1. Polar components shall be inserted according to polarity.
2. When the side components (such as high-voltage ceramic capacitors) are vertically inserted, the screen printing should be turned to the right;When transversely inserted, screen down.When the top components of screen printing (excluding SMD resistor) are inserted horizontally, the font direction shall be the same as the PCB screen printing direction;When installing vertically, the top of the font faces right.
3. When the resistance horizontal and horizontal insertion is carried out, the error color ring should be turned to the right;In horizontal and vertical installation, the error color ring is downwards;When the resistance is inserted vertically, the error color ring faces the plate.
四. Welding requirements
1. The pin height of the insertion element on the welding surface is 1.5-2.0mm.SMT components shall be flat to the plate, solder joints shall be smooth and burr free, slightly arc shaped, soldering tin shall exceed 2/3 of the welding end height, but not exceed the welding end height.Less tin, solder ball or solder covering patch is not good.
2. Solder joint height: single panel of solder climbing pin height shall be no less than 1mm, double panel shall be no less than 0.5mm and shall be tin permeable.
3. Welding spot shape: conical shape and covered with the whole welding plate.
4, solder surface: smooth, bright, no black spots, flux and other sundries, no spikes, pits, pores, copper dew and other defects.
5. Solder spot strength: fully wetted with pad and pin, no virtual welding or false welding.
6. Solder joint cross section: the element shear pin should not be cut to the solder joint as far as possible, and there is no crack of solder on the contact surface between the pin and the solder.No barbed and barb in section.
7. Pin seat welding: The pin seat requires the bottom sticking board to be inserted with proper position and correct direction. After the pin seat is welded, the float height of the bottom shall not exceed 0.5mm, and the skew of the base shall not exceed the screen printing frame.Row of pins should also be kept in order, do not allow forward and backward dislocation or uneven.
To prevent PCBA damage, the following packaging should be used during transportation:
1. Container: Anti-static circulation box.
2. Isolation material: anti-static pearl cotton.
3. Spacing: there is a distance of more than 10mm between PCB board and board, and between PCB board and box body.
4. Place height: there is a space of more than 50mm from the top surface of the revolving box, so as to ensure that when the revolving box is stacked, it should not be pressed to the power supply, especially the power supply with wires.
wash board requirements
The board surface should be clean, wuxi beads, component pins, stains.In particular, the solder joint of the plug-in surface should not see any dirt left by the welding.When washing the board, the following components shall be protected: wires, connection terminals, relays, switches, polyester capacitors and other corrosion-prone components, and the relay shall not be cleaned by ultrasonic waves.