PCB Tech - Inspection method for flow soldering quality of PCB assembly

When the PCB assembly operation equipment Mounter completes the current operation and converts the production plan into another Mounter plan, the PCB assembly operator needs to reprogram each data of the mounter in time, replace the feeder, adjust the substrate transportation organization and positioning table, and adjust and change the mounting head, which is also called reprogramming. How should the manual operation of PCB assembly be carried out?

Step 1: first, system reprogramming: SMT equipment Mounter system generally adopts two programming methods: manual programming and SMT Mounter computer programming. Many low-level mounters usually use manual teaching programming, while fully active mounters such as huaweiguochuang Mounter can completely use computer automation for programming.

Step 2: replace the original production feeder: in order to reduce the time for SMT equipment Mounter to replace the feeder, the more common method is to use the "quick release" feeder, and the faster method is to replace the feeder structure, so that the feeder of each element of SMT Mounter factory on the substrate type of SMT Mounter is installed on a separate feeder frame.

Step 3: adjustment of transmission organization and positioning table: when the size of the replaced substrate plate is different from that of the current device, the width of the substrate plate positioning table and the transportation organization of the transported substrate plate shall be adjusted. The full-automatic Mounter can be actively adjusted under program control, and the SMT machine of the next level can be manually adjusted.

Step 4: replace the mounting head: SMT mounting machine when the component type to be installed on the substrate exceeds the device scale of the placement head, or when changing the substrate type, the mounting head of SMT mounting machine is often replaced or adjusted. Most automatic mounting machines can actively replace and adjust the mounting head under program control, Some small brand mounters need to perform such operations manually.

The common inspection methods of SMT Mounter are as follows:

1. The visual inspection method can detect the common faults of SMT patch type according to visual effect, smell, hearing and touch, visually check whether the wiring, SMT patch type tin dots and PCB board electronic components are wrong, install the battery after confirmation, and listen to whether there is abnormal sound after power on. If there is no abnormal sound, smell whether there is burning smell, and touch the transistor by hand to see whether it is hot, See if the electrolytic capacitor is cracked.

2. Resistance method use mf47 digital multimeter to check whether the resistance value of resistance chip electronic components in the circuit is correct, whether the capacitor is broken, broken down or leakage, and whether the crystal diode and transistor are normal.

3. Voltage method use the DC voltage gear of mf47 digital multimeter to check whether the static working voltage of the power supply and transistor is correct. If it is incorrect, find out the reason, and check the AC voltage value at the same time.