Selection principle of SMT reflux temperature test point and management method of furnace temperature tester

In the SMT chip processing production process, the setting of reflow furnace parameters is the key to affect the welding quality. Through the temperature curve, it can provide an accurate theoretical basis for the setting of reflow furnace parameters. In most cases, the temperature distribution is affected by the characteristics of the assembled circuit board, the characteristics of the solder paste and the capacity of the reflow furnace used.

1、 Selection principle of reflux temperature test points

1. Select 4~6 test points on the physical board. Select 3-5 points on the side with more components of the physical board and 1 point on the side without components.

2. Special components: components with large area and large heat absorption need to be set as separate temperature measurement points.

3. Important components: such as BGA, QFP, PLCC, etc., need to set temperature measurement points separately.

4. The test points shall be scattered as much as possible: the distribution of temperature measurement points shall be scattered throughout the PCB as much as possible.

5. Component density: temperature measuring points shall be set in the area with dense components for measurement.

6. Places prone to poor quality: temperature measuring points shall be set at the points prone to poor quality for control.

7. Monitor the temperature difference between the upper and lower boards, and set a test point at the bottom of the PCB.

2、 Management measures for furnace temperature tester

1. The furnace temperature tester can only be used to test the reflow furnace temperature curve and wave soldering temperature, and cannot be used for other purposes.

2. The furnace temperature curve tester is only allowed to be used by technicians. Do not use it without permission.

3. The furnace temperature curve tester must be tested in strict accordance with the provisions of the furnace temperature test method.

4. After the furnace temperature curve tester is used up, it must be put back into the storage box of the furnace temperature tester to avoid damage.

5. The internal 9V memory battery should be replaced regularly, and it is recommended to replace it every three months.

6. SMT chip processing plants need to calibrate once a year. The error is within 2 degrees.

7. The borrowing of the furnace temperature tester requires the consent of the supervisor and the borrowing records (name of the borrower, borrowing time, pre return time, etc.).

8. The fault of the furnace temperature tester needs to be repaired by professionals, and it is not allowed to disassemble without permission.