Professional terminology in SMT chip processing technology

2020-12-11 17:31:01

Professional terminology in SMT chip processing technology


The SMT patch processing process is a process used to patch objects. It can decorate objects very well. The SMT in the SMT patch processing process is an electronic assembly technology. It has many advantages. The assembly density is very high and the volume is small. There are many professional terms in the SMT chip processing technology. What do these professional terms refer to?


  1, SMT processing surface mount component (SMA): the printed board assembly that uses surface mount technology to complete the assembly.


  2, reflow soldering: by melting the solder paste pre-allocated on the PCB pad, the connection of the surface mount components and the PCB pad is realized.


  3, wave soldering: The molten solder is sprayed through a special equipment into the solder wave required by the design, so that the PCB pre-installed with electronic components can pass through the solder wave to realize the connection between the component and the PCB pad.


  4, fine pitch: less than 0.5mm pin pitch.


  5. Pin coplanarity: Refers to the vertical height deviation of the surface mount component pins, that is, the vertical distance between the highest and lowest pin bottom of the pin. Its value is generally not greater than 0.1mm.


  6. Solder paste: A solder paste with a certain viscosity and good thixotropy is mixed by powdered solder alloy, flux and some additives that play a role in viscosity and other functions.


  7, curing: under certain temperature and time conditions, the process of heating the patch glue of the components to temporarily fix the components and the PCB board.


  8, patch glue or red glue: a colloid with a certain initial viscosity and shape before curing, and sufficient bonding strength after curing.


  9. Dispensing: The process of applying patch glue to the PCB during surface mounting.


  10. Dispenser: equipment that can complete the dispensing operation.


  11. Mounting: The operation of picking up surface mount components from the feeder and placing them on the specified position on the PCB.


  12, SMT splicing tape: used to connect the feeder tray to the tray during the patch processing, which can be connected without stopping, saving a lot of time and raw material costs.


  13. Mounter: A special process equipment that completes the surface mount component mounting function.


  14, hot air reflow soldering: reflow soldering that is heated by forced circulating hot air.


  15. Patch inspection: During or after patching, it is a quality inspection for any missing, misplaced, wrong, damaged components, etc.


  16, stencil printing: the printing process of using a stainless steel plate to print solder paste on the PCB pads.


  17. Automatic stencil cleaning wipe paper: installed on the printing machine for automatic cleaning of excess solder paste during the stencil printing process.


  18. Printing machine: In SMT, special equipment used for stencil printing.


  19. Post-furnace inspection: quality inspection of PCBA soldered or cured in a reflow oven after the patch is completed.


  20, pre-furnace inspection: After the patch is completed, the quality of the patch is inspected in the reflow oven before soldering or curing.


   21. Rework: Repair process to remove local defects of PCBA.


  22. Rework workbench: a special equipment that can rework PCBA with quality defects.