PCBA Tech - SMT material handling criteria and quality inspection

 Material handling is very important in SMT patch processing plants, and there must be outstanding material handling guidelines and handling methods.

  (1) Material handling

  1. Guidelines for SMT material handling.

  · First-in-first-out: The materials that are put into the warehouse first are used out of the warehouse first.

  · Appropriate quantity when ordering: grasp the timing and quantity of the actions of each link in the warehouse.

  · Accounts are consistent: daily records of bills and items are required to be consistent.

  · Daily inventory: warehouse staff need to check the materials they are responsible for every day, so as to keep the daily accounts consistent.

  · e Management: Systematization and paperless management are realized.

  2. SMT material handling method.

  Kanban processing: list the material information such as material number, quantity, and storage date in the form of a table, and make a kanban and stand on the end of the shelf.

  Storage location management: place different materials in different areas of the shelf, that is, the storage area, rack, and positioning of materials.

  FIFO processing: Advanced materials are first delivered out of the warehouse and put into use, and the feeding months are marked with different colors.

  Region management: Different regions are represented by different colors, which are used as the identification of different materials.

  Defective product handling: Defective products are confirmed by the quality control personnel, and rejected labels are attached, blocked and placed, and returned to the defective product warehouse after processing.

  MSD processing: Because of the hygroscopicity of MSD components, it is necessary to control the exposure time in the air according to their sensitivity levels and fill in the "Humidity Sensitive Components Control Label"

Quality inspection intention and effect in SMT patch processing

1. Awareness of quality inspection intention in SMT patch processing.

  Find and eliminate faults in the process of SMT installation process to complete good process control and improve the good rate of products.

  2. Awareness of quality inspection effects in SMT patch processing.

  Discover shortcomings early, prevent defective products from flowing to the next process, and reduce repair costs; discover shortcomings in time, deal with them in time, prevent the occurrence of scrap products, and reduce production costs.

  3. Cognition of quality inspection techniques in SMT patch processing.

  Visual inspection: Directly investigate and check the quality of SMT products with human eyes. In the production process of SMT practice, there are visual inspection procedures after printing paste, patch, reflow soldering, wave soldering and online inspection, which are printing visual inspection, post-furnace comparison visual inspection, installation visual inspection, and quality inspection.

  Its characteristics are: the cost is low, and the viewing effect is related to the PCB mounting density. In the case of low-density mounting, the reliability, accuracy, and continuity of viewing vary from person to person. In the case of high-density mounting, the reliability, accuracy, and continuity of viewing generally decrease, and the viewing time is correspondingly longer. long.

  AOI inspection: Automated Optical Inspection (AOI), which uses active optical equipment for inspection, is an alternative to visual inspection. AOI inspection process is usually provided after printing paste and reflow soldering.

  Its characteristics are: the detection system has nothing to do with the PCB mounting density, the detection speed is high, the accuracy is high, and the reproducibility is high. The bad results of the detection are directly marked on the PCB by ink or marked with graphic errors on the operating display.

  ICT detection: In-circuit Tester (ICT), that is, line fault diagnosis with a line tester. The ICT inspection process is usually provided after the PCB is assembled.

  Its characteristics are: the ability to diagnose faults is extremely strong. Welding defects such as bridging, empty welding, virtual welding, and wire disconnection can directly show the position of the solder joints; welding defects caused by component defects can also be detected.