Manufacturing method of reflow soldering temperature measuring board

For the production mode of multi variety and small batch, most enterprises use the general temperature curve in order to simplify the workload of setting the temperature curve, that is, some PCBAs with similar thermal characteristics are welded with the same temperature curve. At this time, the test and setting of temperature curve must determine the representative PCBA for test. It includes the size and thickness of PCB outline and representative device packaging. Among them, the most critical is to be representative. We usually call this representative PCBA "temperature measuring board".

In order to get an accurate and effective temperature curve of the furnace, it becomes very critical whether the production of the temperature measuring plate can accurately reflect the effectiveness and accuracy of the temperature curve of the reflux furnace, so how to make a qualified temperature measuring plate?

1、 Selection principle of temperature measuring board

1. PCB that is completely consistent with the tested product is preferred for temperature test

2. If there is no consistency, it is preferred to choose the one with the same thickness and the same size of key test devices for temperature test.

3. If there is no BGA complex device on the product, the product can be used for temperature test.

2、 Selection of temperature measuring points

1. It is defined according to the layout and size of the devices on the board, the direction of entering the reflow furnace, and the relationship between the width of the board and the reflow track

Selection principle of temperature measurement points.

2. Selection of the hottest spot (left in and right out of the furnace) this rule considers that the board is cool in front and hot in the back. It is considered that the hottest spot of the board is the breeze blowing on some devices in the upper right corner of the board.

3. Selection of the coldest point. According to the above estimation, the coldest point of the board is the device in the lower left corner of the board entry direction.

3、 Selection of temperature measuring points

1. Thermocouple temperature range: -200 degrees -400 degrees, and the accuracy is plus or minus 1.5 degrees at 200-250 degrees. The thinner the temperature measuring wire is, the more sensitive it is, but it is not durable.

4、 Fabrication of temperature measuring probe

1. The temperature measuring point is the welding head led out by the lead wire. The thermocouple head should be butted against the temperature measuring line and welded with high-temperature tin wire.

2. Cover the surrounding area with red glue, and only expose the probe.