PCB Tech - ​ Printed circuit board assembly protection specification

Standardize the company's PCBA protection requirements. Reduce PCBA damage during storage and transportation, and improve the product qualification rate of PCBA.

Scope of application

This specification applies to the board protection of PCBA products.

Duties

The production department is in accordance with this specification, and the purchasing department requires the outsourcing processing plant to comply with this specification.

The engineering department provides technical support.

content

4.1 PCBA storage and use environment requirements

4.1.1 The relative humidity of the warehouse where the boards are stored: 45-75%, and the room temperature is 15 degree Celsius～30 degree Celsius.

4.1.2 In the warehouse, special anti-static signs should be posted on the place where the board is placed.

4.1.3 In the PCBA debugging area, related equipment and instruments are fully grounded, and the operator should wear an anti-static bracelet.

4.1.4 The room temperature of the static electricity safe area (point) is 15 degree Celsius～30 degree Celsius, and the relative humidity is 45-75%. It is forbidden to operate in an environment lower than 45% (static sensitive components).

4.1.5 Regularly measure the surface resistance of the ground, desktop, turnover box, etc.

4.1.6 Non-production items, such as tableware, tea sets, bags, woolen fabrics, newspapers, rubber gloves, etc., are prohibited to be placed on the workbench in the electrostatic safety zone (point).

4.1.7 When workers enter the anti-static area, they need to discharge. Operators must wear work clothes and anti-static shoes and socks when performing operations. Electrostatic protection safety inspection must be done before each on-the-job operation, and production can only be done after passing the test.

4.1.8 Wear an anti-static wrist strap during operation, and measure whether the wrist strap is effective every day.

4.2 PCBA packaging protection

4.2.1 It must be an anti-static storage and transportation box

Recommended outer dimensions of storage box: (length*width*height)

Medium size: 530 x 400 x 250mm

Large: 720 X 440 X 400mm

Small size: 480 x 350 x160mm or 350 x 270 x 130mm

4.2.2 Regulations on the anti-static grid inside the storage and transportation box:

4.2.3 Internal structure of storage and transportation box

(1) Use anti-static grid:

The material specifications of the anti-static partition are the same as the anti-static grid, and the thickness of the anti-static foam is not less than 2mm.

(2) Use anti-static foam:

4.2.4 Each piece of PCBA must be packed in an anti-static packaging bag that matches its size.

4.2.5 Different storage and transportation boxes should be selected according to the boards of different structural shapes. The requirements for the storage and transportation boxes are: the boards will not rise above the edge of the storage and transportation box after being put in.

4.2.6 The pushing floor height of the storage and transportation box is less than 2 meters.

4.3 PCBA packaging protection of outsourcing processing plants

4.3.1 Each PCBA must be packed in an anti-static packaging bag that matches its size.

4.3.2 The outer layer of each PCBA packed in an anti-static packaging bag needs to be wrapped with anti-static foam. If the PCBA is small (the area of the PCBA is less than 50X100mm, and the thickness of the PCBA is less than 20mm), multiple PCBAs are allowed to be laminated together. Wrap with anti-static foam.

4.3.3 Different storage and transportation boxes should be selected according to the boards of different structures and shapes. Refer to 4.2 for the use of storage and transportation boxes. Packing requirements: the boards will not rise above the edge of the storage and transportation box after being put in.

4.3.4 The relative humidity of the warehouse where the boards are stored: 45-75%, the room temperature is 15 degree Celsius～30 degree Celsius, and the temperature is not too high or too low.

4.3.5 In the warehouse, special anti-static signs should be posted on the place where the board is placed.

4.4 Protection requirements during commissioning

4.4.1 When distributing the board, the board must be kept in an anti-static bag, and the board must not be taken out of the anti-static bag in the storage box.

4.4.2 When testing the board, take one piece from the turnover box, test one piece, put one piece, and don't pile it on the table.

4.4.3 The power-on test must follow the power-on and power-off sequence: low voltage - high voltage - signal voltage. The outgoing sequence is reversed. At the same time, note that the polarity of the power supply cannot be reversed, and the power supply voltage must not exceed the rated value.

4.4.4 Each PCBA must be packed in an anti-static packaging bag that matches its size.

4.4.5 Different storage and transportation boxes should be selected according to the boards of different structures and shapes. The requirements for the storage and transportation boxes are: the boards will not rise above the edge of the storage and transportation box after being put in.

Refer to 4.2 for the use of storage and transportation boxes.

4.4.6 For small rectangular boards (the area of the PCBA is less than 50X100mm, and the thickness of the PCBA is less than 20mm), when the storage and transportation box is insufficient, the following stacked placement can be carried out:

Anti-static foam-"PCBA with packaging -> Anti-static foam -> PCBA with packaging -> Anti-static foam

The height of all boards after being put in will not be higher than the edge of the storage and transportation box.

4.4.7 Refer to the above requirements for special-shaped plates.

4.4.8 When the quantity of PCBA is small, that is, when the quantity of PCBA is less than 1/3 of the total quantity that can be placed in the storage and transportation box, please choose a smaller transfer box and place it according to 4.4.6.

4.5 Protection requirements when moving in the workshop

4.5.1 During transportation, it must not fall to the ground, and must not leave the package arbitrarily.

4.5.2 The board should be kept stable during transportation, and it should not be violently collided to cause damage or deformation of the device.

4.5.3 Handle with care during transportation to prevent damage to components.

4.5.4 When PCBA is in and out of the warehouse, if the number of PCBAs is small and the PCBA size is very small, please refer to the operation according to 4.4.6-4.4.8.

4.5 Protection during assembly operations

When assembling, take one piece from the packing box, tube, and plate, install one piece, put another piece, and don't stack it on the table. When assembling, visually check whether the board is damaged.