Author: Jack Wang
Do you want to know how the quality of "solder paste" is managed and controlled during the PCB assembly process?
PCBMASTER will help you understand it within just 1 minute ! ! !
Friends working in the Surface Mount Technology (SMT) industry are all aware that many of the defects in SMT are caused by solder paste printing. To better control the quality of printed solder paste, SPI has been introduced into the SMT industry. SPI stands for Solder Paste Inspection. SPI is widely applied in SMT manufacturing, mainly due to the development of the current electronics manufacturing industry. So, what role does SPI play in SMT contract manufacturing? Next, PCBMASTER will explain it to you, and we hope it will be of some assistance to you!
1. The working principle of SPI is to utilize the principle of laser projection. A high-precision red laser (with a precision of up to 15 microns) is projected onto the surface of the printed solder paste, and then a high-resolution digital camera is used to separate the laser profile. Based on the horizontal fluctuations of the profile, the thickness changes of the solder paste can be calculated, and a distribution map of the solder paste thickness can be drawn. In this way, it is possible to monitor the printing quality of the solder paste and reduce the occurrence of defects.
2. SPI is usually installed after the SMT solder paste printer. After the printed circuit board is printed with solder paste, it will be conveyed to the SPI equipment via the track for inspection. Can this improve the production output of SMT? The answer is yes. More importantly, it is about how to use SPI to screen out the PCBs with poor solder paste printing quality and then trace the causes of the defects in the printed solder paste in order to solve the root problems.
3. As today's electronic products are evolving towards precision and miniaturization, many electronic components manufactured through SMT have extremely high precision. Therefore, during the component mounting process, the quality requirements for the solder paste printed on the surface of the PCB are also very stringent. If the quality of the solder paste printing can be detected before SMT, it will definitely be more effective than detecting it after the SMT reflow soldering process. This is because a Printed Circuit Board Assembly (PCBA) with poor quality after reflow soldering needs to be repaired using a soldering iron or more complex tools during the repair process, and any slight carelessness may damage the PCBA. Hence, SMT foundries equipped with SPI inspection equipment can avoid such problems.
4. The contents of SIP inspection include: the quantity of solder paste printing, the thickness of solder paste printing, the area of solder paste printing, the flatness of solder paste printing, whether there is any offset of the solder paste, whether the shape of the solder paste printing has sharp corners, and whether the solder paste prints are connected.
5. SPI is a quality control measure in the SMT manufacturing process. If used properly, it can effectively enhance product quality and reduce manufacturing costs. However, if SPI is merely a decorative item in the SMT workshop, it will only affect production efficiency. If SPI issues an alarm, the quality of the solder paste printed on the PCB must be investigated, and the defect rate should be controlled at the lowest possible level. SPI in SMT contract manufacturing can not only control the quality of solder paste printing but also manage and reduce the subsequent maintenance costs, which is conducive to improving production capacity and increasing profits.
As electronic manufacturing products are becoming increasingly precise, the requirements for PCB assembly are also getting higher and higher, and the quality of printed solder paste is becoming more and more crucial. SPI can effectively ensure good solder paste printing quality and significantly reduce potential quality risks.
If you want to learn more about PCB assembly, PCBMASTER is always ready to serve you.
Author: Jack Wang