Temperature tester is a necessary part of the preheating section is his, his test is to control the preheating temperature tester, if short heat problems, then his accuracy will be a problem, here we take a look at the main principle of temperature tester operation!

The temperature curve test instrument as much as possible to set the thermocouple test points, in order to fully reflect the true state of printed circuit board part heating, such as printed circuit board of the center and the edge heating level is not the same, large volume components and small heat capacity and heat sensitive components of different components must be set test point. The temperature curve test instrument, refers to the instrument gives a temperature curve, a temperature meter, temperature change especially specifically in SMT industry to test products stove. The temperature curve refers to the SMA through the back, SMA curves of some points on the temperature change with time. Temperature curve provides an intuitive method to analyze the temperature change of a component in the whole reflow process. This is very useful for obtaining the best welding performance, avoiding damage to the components due to overheating, and ensuring the quality of the welding.

The following from the beginning of a brief analysis of the preheating section. Preheating section: this area is the purpose of the room as soon as possible to achieve second PCB heating, a specific target, but the heating rate should be controlled in the appropriate range, if excessive, will produce thermal shock, circuit boards and components may be damaged, too slow, while the solvent is not sufficient, the influence of welding quality. As the heating rate is fast, the temperature difference is large in the back section of the SMA. To prevent thermal shock damage to components. The general provisions of the maximum speed of 40C/S. However, the usual rate of rise is set to 1~30C/S. The temperature rise rate of the typical 20C/S. insulation section: refers to the temperature from 1200C~1500C to the melting point of the solder paste region. The main purpose of the thermal insulation section is to make the temperature of each component of the SMA tend to be stable, to minimize the temperature difference. Give enough time in this area so that the larger the temperature to catch smaller components, and ensure the full volatilization of solder flux. By the end of the heat preservation section, the oxide on the pad, the solder ball, and the element pins are removed, and the temperature of the whole circuit board is balanced. It should be noted that all the components in the SMA should have the same temperature at the end of this section, or enter the return flow section will be because of the various parts of the temperature is not all kinds of bad welding phenomenon.