How to avoid the Parts Falling on the First Side During the Second Reflow Soldering of SMT (Part 1)

With the rapid development of mobile phone technology, EMS in mainland China has reported serious shortages of labor from time to time. Secondly, Industry 4.0 has made EMS factories increasingly demand for automation. Therefore, many parts that may not be able to pass the SMT process are now also All parts are required to comply with the PIH process.

1. Put red glue under or beside the part

In fact, in the early SMT production lines, the glue dispenser is a necessary equipment, because the SMD parts that have been glued can be wave soldered, but most of the SMT lines now have almost no such equipment. If you don’t have a dispenser, you have to manually dispense glue. I don’t recommend manual work, because manual work consumes manpower and man-hours, and the quality is more difficult to control, because if you are not careful, you will encounter other patches that have already been placed. For good parts, if there is a machine, the quality of the dispenser is of course better to be controlled.

The purpose of applying red glue is to adhere the parts to the circuit board, so the red glue must be applied to the circuit board and stick to the parts, and then pass through the reflow oven, and use the high temperature of the reflow oven to solidify the red glue.

Red glue is irreversible glue and cannot be softened by heating. If the red glue is to be spotted under the part, the dispensing operation must be applied immediately after the solder paste is printed on the circuit board, and then the heavier part should be covered on it. It should be noted that there is a risk that the red glue dots will prop up the parts under the parts, so generally heavy and large parts will work in this way.