Get the best solder joint quality
Solder joint quality is the key factor to ensure the final quality of printed circuit board components. Even when the process is well adjusted, most defects usually originate from steel screen printing. One reason is that the stencil printing process with steel mesh always makes a compromise between the optimization of the amount of solder paste required for large components and small components. Although the stepped steel mesh has a certain degree of optimization effect, it requires additional cost. At the same time, the change of solder paste amount and the minimum "step distance" are limited. In contrast, spray printing can completely control the amount of solder paste, including three-dimensional printing (apply solder paste on each solder paste point). Default settings are provided by CAD data. Users can freely fine tune the amount, position, coverage area and height of solder paste on each pad, component and package on the PCB. This will be able to optimize solder paste deposition even on the most complex and high-density assembled substrates. For example, there is a user using spray printing technology, whose products are assembled with 69 components per square centimeter. The packaging system can further improve the quality. Compared with steel screen printing, spray printing significantly reduces the number of variable parameters and related potential human errors. The software control ensures a very fast and optimized printing process. The on-site correction of the solder paste amount can take effect in a few seconds. In addition, the printing program can be automatically expanded and aligned according to the PCB reference. The non-contact technique is independent of any substrate warpage.
Easy handling of complex processes
In the SMT industry, there is an obvious trend that the packaging is becoming smaller and smaller, and the complexity of substrate design and component assembly density are becoming higher and higher. These challenging applications are gradually leaving the traditional steel screen printing technology. A recent report from the international alliance of electronic manufacturers (iNEMI) gives a more powerful explanation of this trend. The report says: "when the substrate involves hybrid technology, steel screen printing will reach its limit". In terms of solder paste quantity optimization, spray printing can reliably deal with special components, such as QFN and pin in paste components. At the same time, it also opens the door of opportunity for new design. For example, in the 3D substrate, in order to reduce the final component height, more and more grooves are used, and spray printing is the only automatic solution that can complete this task at present. Stacked package (POP) design presents another challenge. Components impregnated with flux or solder paste are dirty and labor-intensive, which is a difficult solution for mass production. Spray printing not only automates this process, but also compensates for any component warpage by optimizing the height and amount of solder paste at each solder joint. The ability to cope with complex components and packaging means that this technology is most suitable for secondary printing. The inkjet printer can deposit solder paste on the substrate after previous steel screen printing. This allows manufacturers to avoid expensive and time-consuming manual operations.
Realize return on investment
Investment in new technologies should carefully consider the coherence between current and future needs. In order to exceed the original production capacity, the investment of "just in case" is very simple, but if the setting of the whole production process does not adapt to the production capacity level, the expensive equipment will not be fully utilized. Inkjet printing has greater flexibility, which can help manufacturers improve their entire production process, shorten setup and conversion time, and improve equipment utilization. It can easily and consistently realize high-quality solder joints to meet the requirements of various applications and complex substrate design. Coupled with the obvious improvement of user responsiveness, spray printing has the best and fastest return on investment. There is no doubt that more and more manufacturers will choose the emerging spray printing technology to replace the steel screen printing machine.
