The placement reflow soldering must pay attention to speed accuracy. Speed is divided into 1,1 + 1,1 + 2,1 + 3 other wiring methods, accuracy, LED light products, power supply, mobile phone board, computer motherboard.

　　 the speed of second-hand placement machine to reflow soldering, one is a small reflow W-635, a single high-speed machine is equipped with a reflow W835, 1 + 1 wiring is required. With a medium-sized reflow W8800, wiring above 1 + 2 must be equipped with a large eight-temperature zone, the ten-temperature zone ranges reflow soldering. In terms of accuracy, LED light products are equipped with general small reflow ovens 635, 640, 835 other precision products, mobile phone boards, computer motherboards other precision products with IC, QFP, BGA need to be equipped with large reflow soldering, so as to meet the product Requirements, so the speed accuracy must be taken into account when wiring, the product is precise, a single multi-functional placement machine must be equipped with a large reflow soldering, higher requirements need to be equipped with nitrogen reflow soldering. In addition, the solder paste is generally refrigerated in a refrigerator before use. After being taken out, it should be returned to room temperature opened for use. Otherwise, the solder paste easily absorbs moisture generates solder beads when reflowed. Making opening of templates. We generally make templates based on the pads on the printed board, so the opening of the template is the size of the pads. When printing solder paste, it is easy to print the solder paste onto the solder resist layer. Shenzhen second-hand chip mounter thus generates solder beads during reflow soldering. Therefore, we can make a template in this way, reduce the opening of the template by 10% compared to the actual size of the pad. In addition, the shape of the opening can be changed to achieve the desired effect. Here are some recommended pad designs: The thickness of the stencil determines the printed thickness of the solder paste, so appropriately reducing the thickness of the stencil can also significantly improve the solder bead phenomenon. We have conducted such experiments: At first, a 0.18mm thick template was used. After reflow, it was found that the solder next to the resistance-capacitance component was serious. Later, a template was remade, the thickness was changed to 0.15mm, the opening form was as shown above. In the former design, reflow soldering essentially eliminates solder beads.