PCB Technical - Tooling preparation before PCBA production and processing

1. Tin furnace

(1) PCBA parameter requirements:

1. Flux density

90-BY820C-ZH0 (Baoyue) 0.815±0.005g/ml

2. Preheating temperature:

Single-panel preheating is one 900 degree Celsius, preheating two is 10010 degree Celsius; double-layer board and multilayer board preheating one is 1000 degree Celsius, preheating two is 11010 degree Celsius;

3. Soldering temperature: 2505C for single-sided board; 2455 degree Celsius for double-layer and multi-layer boards

4. Welding time 2～4S

(2) Check requirements:

1. Testing tools: density meter, process temperature testing equipment.

2. Welding quality inspection (cycle) inspect 5 boards every 1 hour

3. Recorded manufacturers and origins of solder, pine perfume, plate washer water, antioxidants, etc.;

4. Check frequency: once an hour and make a control chart (control poor welding according to PPM value).

2. Self-check of grounding resistance tester

(1) Parameter setting

Constant current output 10A, output voltage frequency: 50Hz, test time: 5 seconds, analog resistance: 0.15Q

(2) Testing requirements

Perform self-inspection every time you go to work and make a record of the "Ground Resistance Tester Checklist";

(3) Check (clear)

The 9611/13 intelligent automatic ground resistance tester is used as an example. Purpose: In order to eliminate the resistance of the test line and the contact resistance

1. Put the instrument in the standby state, first preset the test time to "LLL";

2. Short-circuit the two test wires and press the "Start" key to test. At this time, the ground resistance measurement value display window displays the actual measured value. If the display is "0.000", it means the instrument has been calibrated. If the display is not "0.000", then Press the "calibration" key for about 2 seconds to change the value to "0.000", and finally press the "stop" key, the instrument calibration is normal; note: the calibration must be preset to "LLL" for the calibration to be valid .

(4) Self-inspection

1. Connect the two test wires of the grounding resistance tester to the two ends of the analog calibration resistance respectively;

2. Press the "start" key to test, the instrument should alarm;

3. If there is no alarm, all TV sets produced after the last inspection must be reworked.

Note: The external power supply (adapter) does not need to test the grounding resistance.

3. Self-inspection of withstand voltage tester

(1) Parameter setting (production process) Voltage: Class I equipment standard AC1500y Class II equipment standard AC3500V Test time: 5S Leakage current: Class I equipment 0.1 (L) ~ 10 (H) mA, Class II equipment 0.5 (L) ~ 10 (H) mA

(2) Testing requirements

Perform self-inspection every time you go to work, and make a record of the "Hot Pressure Tester Checklist";

(3) Self-inspection method

1. Connect the 330K/36W analog resistance to the ground wire and high-voltage output terminal of the high-voltage tester, start the withstand voltage tester for testing, and the instrument should alarm;

2. Open the ground wire of the withstand voltage tester and the high-voltage output terminal, start the withstand voltage tester for testing, and the instrument should alarm;

3. If there is no alarm, all PCBA products produced after the last inspection must be reworked.

4. Soldering iron temperature check

Use a soldering iron temperature tester to detect the temperature of the constant temperature soldering iron. When checking, keep a small amount of molten tin on the tip of the soldering iron. If the temperature is not within the required range, adjust the temperature for one minute and then check until the test value meets the requirements. Calibrate once a week, and fill in the soldering iron inspection record form (save for half a year) for future reference.

5. Check the torque of the torque meter

(1) PCBA inspection method

Put the torque meter on the tightened screw, turn the torque meter in the opposite direction, and measure the torque when the screw just loosens;

(2) Detection frequency

Workers in PCB factories must check once a day before going to work