As a common parts of SMT machine, there will be various problems in the process of working, such as unable to pick, unable to place or mounting wrong position. So what are the reasons for these mistakes? Let's talk about it.
(1) SMT nozzle wear, deformation, blockage and damage resulting in insufficient air pressure and fail to mount SMT components, so it is necessary to regularly check the wear degree of SMT nozzle and replace the serious ones.
(2) The influence of SMT feeder. The feeder feeding is not good (the feeder gear is damaged), the belt hole is not stuck on the feeder gear, foreign matters under the feeder, the clip spring is worn, and the feeder cover, spring and other operating mechanism of the pressure band are deformed and rusted, so as to cause the components to be deviated, clamping piece or unable to mount the components. Therefore, regular inspection and treatment should be carried out to avoid the waste of SMT parts.
(3) Vacuum negative pressure is insufficient. When the SMT nozzle picks the component, a certain negative pressure will be generated at the SMT nozzle, and the component will be adsorbed on the SMT nozzle. Generally, the negative pressure detection method is used to determine whether the SMT nozzle pickup element is abnormal. When the negative pressure sensor detection value is within a certain range, the machine thinks that pickup is normal, otherwise, it is considered to be poor. The vacuum negative pressure should be above 53.33kpa when the component is picked, so that there is enough vacuum to absorb the component. If the vacuum negative pressure is insufficient, it will not be able to provide enough suction to pick the components. In use, we should often check the vacuum negative pressure, and regularly clean the SMT nozzle. At the same time, we should pay attention to the pollution of SMT vacuum filter element on each mounting head. Its function is to filter the air source reaching the SMT nozzle, and replace the blackened ones to ensure smooth air flow.
(4) The influence of suction height. The ideal suction height of the SMT nozzle is to press down 0.05mm when the SMT nozzle is in contact with the surface of the element. If the pressing depth is too large, the component will be pressed into the feeding tank and not be able to pick up. If the suction condition of a component is not good, the height of suction can be adjusted slightly upward, such as 0.05mm. If all the components on a certain material table are not well absorbed, the solution is to move the height of the material platform upward in the system parameters.
(5) There are some quality problems. There are quality problems in the packaging of chip components produced by some manufacturers, such as large error of perforation spacing, excessive adhesion between paper tape and plastic film, and too small size of material slot. These are the possible reasons why the components can not be picked.