In SMT patch processing, the placement quality of components is very important, which affects the stability of the product. The main factors affecting the placement quality in SMT patch processing are as follows:
1. The components must be correct
During the patch processing, the type, model, nominal value, polarity and other characteristic marks of each assembly tag component are required to meet the requirements of the product assembly drawing and schedule, and the wrong position cannot be pasted.
2. The position must be accurate
(1) The ends or pins of the components should be aligned and centered with the land pattern as much as possible, and ensure that the solder ends of the component contact the solder paste pattern accurately;
(2) The component placement position must meet the process requirements.
3. The pressure (patch height) should be appropriate
The pressure of the patch is equivalent to the height of the Z axis of the suction nozzle, and the height should be appropriate and appropriate. If the mounting pressure is too small, the solder ends or pins of the components float on the surface of the solder paste, and the solder paste cannot stick to the components, which is prone to position shift during transfer and reflow soldering. In addition, because the height of the Z axis is too high, the components are dropped from a high place during the placement process, which will cause the placement of the placement to shift. If the pressure of the patch is too high, the amount of solder paste squeezed out is too much, it is easy to cause the solder paste to stick, and it is easy to cause bridging when reflow soldering. At the same time, the position of the patch will be shifted due to sliding, and the components will be damaged in severe cases.
