How to do heat test for PCB board

In order to ensure the quality of the PCB circuit board, it is necessary to carry out a temperature resistance test. The purpose is to prevent the PCB from experiencing adverse reactions such as bursting, blistering, and delamination at excessively high temperatures, resulting in poor product quality or direct scrapping. The temperature problem of PCB is related to the bearing temperature of raw materials, solder paste and surface parts. Usually, the maximum temperature of the PCB circuit board can withstand 300 degrees for 5-10 seconds; the temperature is about 260 for lead-free wave soldering, and about 240 for lead-free wave soldering. Spend.

So how does the PCB do heat resistance testing?

1. Prepare PCB samples and tin furnaces;

Sampling 10*10cm substrate (or laminated board, finished board) 5pcs (copper-containing substrate without foaming and delamination)

Substrate: 10cycle or more

Lamination plate: LOWCTE15010cycle or more

HTg material: more than 10cycle

Normal material: 5cycle or more

Finished board: LOWCTE1505cycle or more; HTg material more than 5cycle; Normal material more than 3cycle.

2. Set the temperature of the tin furnace to 288±5 degrees, and use the contact thermometer to measure and correct;

3. First dip the flux with a soft brush and apply it to the surface of the board; then use the crucible tongs to take the test board and immerse it in the tin furnace. After 10 seconds, take it out and cool it to room temperature. Visually check whether there is foaming and bursting of the board, this is 1 cycle ;

4. If there is a problem of blistering and bursting the board visually, stop tin immersion and analyze the initiation point f/m immediately; if there is no problem, continue to cycle until the board bursts, with 20 times as the end point;

5. The blistering area needs to be sliced and analyzed to understand the source of the detonation point and take pictures.

The above is about the temperature resistance of PCB circuit boards. For the temperature resistance of PCB circuit boards of different materials, it is necessary to understand in detail, and not exceed the maximum limit temperature, so as to avoid the problem of scrapping of PCB circuit boards.