Types and Development History of Solder Paste Printers

In the early stage of the SMT industry's development, I was fortunate to join Nitto Equipment Company in 2000 to engage in the manufacturing of SMT equipment, and have witnessed the development of solder paste printers all the way. In the early days of SMT, solder paste was mainly applied to PCBs through screen printing, so the original name of the solder paste printer was solder paste screen printer. As the name implies, it achieves the purpose of applying solder paste to PCBs through a screen printing stencil. Manual solder paste printing was almost the only method in the early stage. Solder paste printing is derived from the screen printing technology of the printing industry, which we commonly see in advertising text printing, packaging printing and other fields. Its embryonic form is similar to leaflet printing devices. In actual production, considering that screen printing stencils have high consumption and are prone to wear and damage, the material was replaced with a steel stencil structure—its advantage is high wear resistance and long service life, but the disadvantage is high cost, as a separate steel stencil is required for each product. Semi-Automatic Solder Paste Printer Steel stencil printing solved the problems of service life and wear in solder paste printing, but the unstable quality of manual printing led to an urgent market demand for printed products with stable quality and good consistency. Thus, semi-automatic solder paste printers appeared on the market. Its advantage is stable printing quality, while the disadvantage is that quantitative indicators all rely on experience, such as target focusing and printing accuracy. Under such circumstances, the market has an additional demand for visual inspection for solder paste printers. Semi-Automatic Visual Solder Paste Printer The semi-automatic visual solder paste printer came into being and perfectly solved the problem of visual management in solder paste printing history. With the assistance of visual software and industrial cameras, it can magnify PCBs, realize one-stop operations including calibration and alignment of steel stencil solder paste holes and visual management of solder paste quality. Finally, the only remaining disadvantage is low automation which requires manual participation, thus creating a market demand for fully automatic solder paste printers. Fully Automatic Solder Paste Printer The launch of the fully automatic solder paste printer was highly praised by the market, but it still has a drawback—excessively high cost: one fully automatic solder paste printer costs as much as 2 to 3 semi-automatic ones. In addition, the uneven quality of suppliers on the market also results in vastly different quality of fully automatic solder paste printers. For mass production, it is recommended to use fully automatic solder paste screen printers directly. Most fully automatic solder paste screen printers can be equipped with automatic feeding systems, pre-printing treatment, curing and visual inspection modules, which greatly improve work efficiency and printing quality. There are four main types of solder paste printers: manual, semi-automatic, semi-automatic visual and fully automatic printers (as shown in the chart below). In solder paste screen printing, there are three key elements known as the three Ss: Solder Paste, Stencils and Squeegees. The correct combination of these three elements is the key to ensuring consistent screen printing quality.