profile测试线焊按原理.ppt

1、Measuring of Temperature Profiles in a Reflow System,天马行空官方博客： ；QQ:1318241189；QQ群：175569632,溫度量測作業方法分解圖示,General,Temperature profiles are taken by measuring systems which run through the reflow oven. Temperature sensors are located on different positions on the PCB, and the temperatures during the r

2、un are stored in the internal memory. After passing the oven the system is connected to a PC, the data is then transfered and displayed on the screen.,Temperature Sensors,Most of the measuring systems on the market are working with thermocouples. The thermocouple type is very often K which stands fo

3、r NiCr - Ni and is indicated by the green isolation material of the wire and the yellow connector. For quick and accurate temperature response, the thermocouple should be less in mass and diameter.,do 0,1 mm,Thermocouple Mounting,Fixing the thermocouple wire with Capton tape to the board,Before fixi

4、ng the thermocouple tip , make sure that the two nonisolated wires do not touch each other !,Thermocouple Mounting Defects,If the thermocouple tip is twisted, the temperature is measured at the closest short of the wires to the connector. In the picture left, the temperature is measured at this loca

5、tion and not at the tip !,Thermocouple Mounting with epoxy glue,Fixing the thermocouple tip with epoxy glue to the selected component Disadvantage is the fact, that the glue has to be cured before the board can be used for measuring. Sometimes glue spread to much, or to much glue will affect the tem

6、perature.,Thermocouple Mounting with high temp. solder,Fixing the thermocouple tip with high temp solder to the selected component. This is a quick and safe method to fix the sensors, as long as not to much solder is used.,Thermocouple Mounting Defects,Four thermocouples were mounted in different wa

7、ys to a QFP. This test setup was heated with an hot air blower which was set to a constant temperature. The heat up of the component was very even and homogeneous.,Thermocouple Mounting Defects,T = 24,5 C !,Thermocouple Mounting Defects,T = 24,5 C !,Offering the latest technology, this system is per

8、fect for rework stations. Because you see profiles as they occur the risk of damage to your board or components is virtually eliminated. This systems state-of-the-art data logger boasts the fastest sampling rate in the industry for real-time readings (0.2 seconds on all channels) and an accuracy of 1C. all to give you the reliable data you need for