Main technical indicators of standard reflow welding machine

Reflow soldering technology is a key link in SMT technology, and the quality of SMT products is largely determined by the reflow soldering process technology. Therefore, the reflow soldering technical indicators are the key link in determining the quality of reflow soldering products. JEENOCE would like to share with you the main technical requirements for standard reflow welding machines.

1、 Main technical indicators of standard reflow welding machine

1. The temperature control accuracy of the reflow welding machine should reach ± 0.1-0.2 ℃.

2. Temperature uniformity: ± 1 ° C~2 ° C, the temperature difference at different points in the furnace should be as small as possible.

2. Horizontal temperature difference of the conveyor belt of the reflow welding machine: Traditional requirements are below ± 5 ℃, while lead-free welding requires<± 2 ℃.

3. Temperature curve testing function for reflow soldering machine: If the reflow soldering machine does not have this configuration, a temperature curve collector should be purchased externally.

4. The maximum heating temperature of the reflow soldering machine is generally 210-235 ℃. If lead-free solder or metal substrate is considered, it should be selected above 250 ℃.

5. The number and length of heating zones for reflow soldering machines: The longer the heating zone and the more heating zones there are, the easier it is to adjust and control the temperature curve. Generally, for small and medium-sized production, 4-5 temperature zones and a reflow soldering equipment with a heating length of about 18m can meet the requirements. Lead free reflow soldering should choose a temperature range of 7 or above.

6. The width of the conveyor belt for the reflow soldering machine should be determined based on the size of the PCB, both large and small.

7. Cooling efficiency of reflow welding machine: It should be determined based on the complexity and reliability requirements of the product. For complex and highly reliable products, high cooling efficiency should be selected.

2、 Technical specifications for temperature range of lead-free reflow welding machine

1. Preheating zone

The preheating zone heats up to 175 degrees Celsius for about 100 seconds, from which the heating rate of the preheating zone can be obtained (as this tester uses online testing, it has not yet entered the preheating zone from 0 to 46 seconds, and the time is 146-46=100 seconds. As the room temperature is 26 degrees Celsius, the heating rate is 175 to 26=149 degrees Celsius, and 149 degrees Celsius/100S=1.49 degrees Celsius/S);

2. Constant temperature zone

The high temperature in the constant temperature zone is around 200 degrees, with a time of 80 seconds, and a difference of 25 degrees between high and low temperatures;

3. Reflux zone

The high temperature in the reflux zone is 245 degrees Celsius, and the low temperature is 200 degrees Celsius, with a peak time of approximately 35/S; The heating rate of the reflux zone is 45 degrees/35S=1.3 degrees/S. According to (how to correctly set the temperature curve), it can be seen that the time for this temperature curve to reach its peak is too long. The entire reflux time is approximately 60 seconds;

4. Lingque District

The time in Lingque District is about 100 seconds, and the temperature drops from 245 degrees to around 45 degrees. The speed of Lingque is: 245 degrees to 45 degrees=200 degrees/100S=2 degrees/S.