SuZhou Tonkida Electromechanical Technology Co., Ltd Professional SMT whole line supplier

The preheating temperature and welding temperature setting of wave soldering are very important to ensure the welding quality. The following is a detailed analysis of the preheating temperature and welding temperature Settings for wave soldering:

Wave soldering machine

I. Setting of preheating temperature for wave soldering

The setting of preheating temperature is the precondition of welding quality. The main purpose of preheating is to gradually heat up the PCB board and components, reduce the temperature stress during the welding process, and stimulate the activity of the flux.

Wave soldering temperature curve

1, preheating temperature range:

When there is lead welding, the preheating temperature is generally maintained between 70-90 ° C.

In lead-free welding, due to the low activity of lead-free flux, the activity needs to be stimulated at high temperatures, so the preheating temperature is usually maintained at a high level, such as between 130-150 ° C, or even up to about 150 ° C.

2, preheating time:

The preheating time should be long enough to ensure that the PCB board and components can heat up evenly. Under normal circumstances, the preheating time is between 1-3 minutes, but the specific time needs to be adjusted according to the thickness of the PCB board, the speed of the board and the length of the preheating zone.

3. Heating rate:

The heating rate of the PCB board and components should be controlled within a certain range to avoid the deformation and bending of the PCB board caused by too fast heating. It is generally recommended that the temperature rise rate does not exceed 2 ° C/s.

4. Influencing factors:

The thickness of the PCB board, the speed of the board and the length of the preheating zone will affect the setting of the preheating temperature. For example, when the PCB board is thick, the preheating temperature can be appropriately increased; When the speed of the board is accelerated, the preheating temperature should be increased accordingly.

Second, wave soldering furnace welding temperature setting

Wave soldering preheating zone

The welding temperature of the wave soldering furnace is one of the key parameters of the whole welding system. The appropriate welding temperature can ensure that the solder fully wets the PCB surface and forms a good welding point.

1, welding temperature range:

Lead solder can be wetted between 223 ° C and 245 ° C.

Lead-free solder needs to be wetted at a higher temperature, generally between 230 ° C and 260 ° C. In order to ensure welding quality, the temperature of lead-free welding is usually set in the range of 245 ° C ±10 ° C, or more specifically, between 250 ° C -260 ° C.

2, temperature control:

The welding temperature control requirements are very strict. The gap between the actual welding temperature and the set temperature should be controlled within a small range, such as within 5 ° C (the difference can not exceed 10 ° C when there is a fixture). If the temperature difference is too large, adjust it in time or notify equipment engineers for check.

3. Influencing factors:

The setting of welding temperature also needs to consider the PCB material, the temperature requirements of electronic components, and the company's existing temperature measuring instruments and measurement conditions.