How to control the reflow quality?

Reflow soldering process is to realize the mechanical and electrical connection between the solder end or pin of surface assembled components and the PCB pad by remelting the paste solder pre distributed on the PCB pad.

Reflow soldering technology is not unfamiliar to us in the field of electronic manufacturing industry. In our electronic products, the components on various boards must be welded to the circuit board through reflow soldering process. The advantage of this process is that the temperature is easier to control, oxidation can be avoided in the welding process, and the cost of manufacturing products is easier to control. There is a set of electric heating circuit inside the equipment, which heats the nitrogen to a sufficiently high temperature and blows it to the circuit board where the components have been pasted, so that the solder on both sides of the components melts and bonds with the main board.

1、 How to control the reflow quality, the production process is mainly optimized from these aspects:

1. Set scientific reflow temperature curve and conduct real-time test of temperature curve regularly.

2. Welding shall be carried out according to the welding direction during PCB design.

3. The conveyor belt shall be prevented from vibration during welding.

4. The welding effect of the first printed board must be checked.

5. Whether the welding is sufficient, whether the surface of the welding spot is smooth, whether the shape of the welding spot is half moon, the condition of tin ball and residue, continuous welding and false welding. Also check the color change of PCB surface. And adjust the temperature curve according to the inspection results. The welding quality shall be checked regularly during the whole batch production process.

6. The reflow soldering shall be maintained regularly. Due to the long-term operation of the machine and the attachment of solidified rosin and other organic or inorganic pollutants, regular maintenance and cleaning shall be carried out in order to prevent the secondary pollution of PCB and ensure the smooth implementation of the process.

2、 What should we do and pay attention to in reflow maintenance?

1. It is necessary to formulate the maintenance system of reflow soldering equipment. We must maintain the equipment after using reflow soldering, otherwise it is difficult to maintain the service life of the equipment.

2. Daily inspection and maintenance shall be carried out for all parts, and special attention shall be paid to the conveyor belt to prevent it from being stuck or falling off;

3. When overhauling the machine, shut down and cut off the power supply to prevent electric shock or short circuit;

4. The machine must be stable without tilting or instability;

5. Regularly clean the reflow soldering furnace, mesh belt and condenser, and formulate weekly, monthly and quarterly maintenance plans to ensure the quality of reflow soldering.

For the maintenance and cleaning of reflow equipment, it is recommended that water-based products are safe and environmentally friendly, meet the requirements of current RoHS, reach, Sony 00259, HF and other environmental regulations, and have high cleaning efficiency and low cost.