Card board is in the electronic assembly (PCBA) manufacturing reflow soldering process production practices are more common failure phenomenon, but for the vacuum reflow soldering, the impact of card board phenomenon than ordinary reflow soldering is much greater, so Tortai according to its actual production encounter card board problems and preventive measures and combined with the experience of peers to write the following:
Cardboard phenomenon refers to the welding process, electronic components or PCB board card in the welding platform can not move normally, resulting in poor welding or welding quality is not stable. The main reasons for the cardboard phenomenon are the following:
1、welding platform is not flat: welding platform surface is not flat or has a raised part, will lead to electronic components or PCB board stuck in it can not move.
2、welding platform surface pollutants: welding platform surface pollutants such as oil, dust, etc., will also lead to electronic components or PCB board stuck in the above can not move.
3、The temperature of the welding platform is too high: the temperature of the welding platform is too high, which will increase the adhesion between the electronic components or PCB board and the welding platform, leading to the phenomenon of card board.
4、Insufficient vacuum of the welding platform: vacuum reflow soldering needs to be carried out under a certain vacuum, if the vacuum is insufficient, it will increase the adhesion between the electronic components or PCB board and the welding platform, resulting in the card board phenomenon.
Preventive Measures
In order to avoid the occurrence of the cardboard phenomenon, the following preventive measures can be taken:
1、welding platform to maintain a flat: before using the welding platform, should check whether its surface is flat, such as a raised part should be promptly trimmed.
2、welding platform to keep clean: before using the welding platform, the surface should be cleaned to avoid the presence of oil, dust and other pollutants.
3、Control the temperature of the welding platform: When welding, the temperature of the welding platform should be controlled to avoid excessive temperature leading to increased adhesion between the electronic components or PCB board and the welding platform.
4、Improve the vacuum level: When performing vacuum reflow soldering, the vacuum level of the soldering platform should be ensured to meet the requirements to avoid insufficient vacuum leading to the occurrence of cardboard phenomenon.
5、Use the appropriate welding process: When selecting the welding process, the appropriate welding process should be selected according to the characteristics of electronic components and PCB boards to avoid excessive welding or insufficient welding leading to the occurrence of the jamming phenomenon.
In summary, the cardboard phenomenon is a common problem in vacuum reflow soldering, but can be avoided by taking appropriate preventive measures. In actual production, attention to detail should be paid to ensure the flatness, cleanliness and temperature control of the welding platform, and to ensure that the vacuum level meets the requirements in order to improve the welding quality and productivity.