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   From: 82cd8557e883ba07c637f5a62f382186@example.com   
      
   Step 1: Solder Paste Printing   
   Solder paste printing is the first step in PCBA processing. We apply solder   
   paste to the area of the printed circuit board where components need to be   
   assembled. This step is accomplished by applying solder paste on the stainless   
   steel template, which    
   corresponds to the circuit board, and the solder paste drips from the holes of   
   the template onto the PCB. 96.5% tin is gray and it contains 3% silver and   
   0.5% copper. In order to protect the environment, FS Technology uses lead-free   
   solder paste. The    
   solder paste will be heated and melted in step 3 and form a strong joint   
      
   Step 2: Pick and Place of Components   
   The second step of the PCBA processing flow is to place the components on the   
   PCB, which is completed by a high-speed SMT placement machine. At design time,   
   the PCB designer creates a file, which is used to control the SMT device. The   
   file identifies the    
   X, Y coordinates of the PCB assembly, and thanks to this information, the pick   
   and place machine accurately places the SMD components on top of the solder   
   paste through the vacuum nozzle.   
      
   At the beginning, humans completed the picking and placement of components by   
   manual soldering, but this is obviously not good for large-volume orders. In   
   order to ensure fast turnaround, we use SMT assembly machines, which can   
   ensure the consistency and    
   accuracy of PCBA.   
      
   Step 3: Reflow oven melts and cures solder paste   
   We need to use a reflow oven to melt and solidify the solder paste. It is best   
   to use equipment with ten temperature zones for this process. The PCB is   
   transferred to the reflow oven through the docking station. The oven can   
   generate a maximum    
   temperature of 250 degrees Celsius, which is enough to completely melt the   
   solder paste. The melted solder paste will form a joint at the junction of the   
   PCB and the component, forming a strong solidified solder joint after entering   
   the cooler, which    
   will create a permanent joint between the SMD component and the PCB.   
      
   Step 4: QC Check   
   Due to the influence of many factors, the soldering quality of the circuit   
   board may be poor. Since the circuit board is an essential component in   
   electronic equipment, no matter how small the error is, it will lead to a   
   circuit board short. Therefore,    
   we need to use a variety of detection methods to ensure its quality.   
      
   Manual Inspection   
   Almost all formal PCBA processing companies will require operators to conduct   
   detailed and comprehensive PCB manual inspections. For a well-equipped   
   assembly plant, the purpose of manual inspection is just a guarantee.   
   Different components are installed    
   on the PCBA board, while SMD patch components are smaller, and visual   
   inspection of the circuit board may cause inaccurate detection due to fatigue   
   of technicians. This detection method is more friendly to DIP components.   
      
   AOI Optical Inspection   
   In high-volume assembly orders, AOI inspection is considered effective. This   
   detection method refracts light through the PCBA solder joints, and observes   
   the solder joints from multiple angles to ensure consistency with the standard   
   board. The biggest    
   advantage of this detection method is that it is fast and can process batch   
   orders in a short time.   
      
   X-Ray Inspection:   
   X-ray machines allow operators to observe the internal structure of printed   
   circuit boards to find defects in their inner layers. This kind of testing   
   equipment requires customers to pay extra fees, and usually we use it in   
   complex and advanced circuit    
   boards. If your assembly plant does not have skilled inspectors, please do not   
   attempt this method of PCB inspection as it may result in rework or scrapped   
   PCBs.   
      
   Step 5: Component Soldering   
   Component introduction   
   The PCB itself does not function and provides a carrier for electrical   
   connections to electronic components. Various components are installed on   
   different PCBA boards, including DIP components and SMD components.   
      
   DIP components are a larger and more common circuit board component that are   
   mounted to a circuit board through through hole assembly. These holes are   
   classified as plated through holes (PTH) and non-plated through holes (NPTH).   
   The operator passes the    
   pins of the DIP component through the holes in the PCB. These holes are   
   connected to other holes and vias with copper traces. When these DIP   
   components are inserted and soldered on the PCB, they make electrical   
   connections with other holes in the same    
   PCB as the designed circuit.   
      
   SMD components are the most popular electronic components in modern electronic   
   equipment. The IC chip we often say is one of the SMD components. These   
   components are soldered on the surface of the PCB in the form of patches. With   
   the development of    
   miniaturization trend, SMT assembly technology has gradually replaced DIP   
   assembly.   
      
   Welding type   
   The three most common soldering processes are manual soldering, wave soldering   
   and reflow soldering.   
      
   Manual soldering is a way for electronics enthusiasts to make their own PCBA   
   boards. Electronic enthusiasts insert the pins of the DIP component into the   
   holes of the PCB, and then solder the pins on the soldering surface to death   
   by a welding machine.   
      
   Reflow soldering is usually used in the SMT assembly process, which can easily   
   complete the soldering of SMD components and ensure that these components are   
   not damaged. When you choose a PCBA processing factory, please pay attention   
   to whether the    
   reflow soldering equipment used by the service provider is in ten temperature   
   zones.   
   Wave soldering is an upgraded version of manual soldering, which can complete   
   the soldering work automatically. Once the PTH components are placed on the   
   PCB, the PCB is placed on a conveyor belt and moved to a dedicated oven. Here,   
   a wave of molten    
   solder splashes onto the bottom layer of the PCB, where the component leads   
   are located. This will solder all pins at once.   
      
   Step 6: PCB Functional Test   
   When the PCBA is manufactured we need to test it. Functional test is an   
   essential PCB test, which refers to checking whether the assembled PCBA can   
   operate according to the design.   
      
   If any parameter of the PCBA shows unacceptable results, discard or scrap the   
   PCBA following company standard procedures. The testing stage is very   
   important because it determines the success or failure of the whole PCBA   
   process.   
      
   https://www.fs-pcba.com/step-by-step-to-make-pcba-board/   
      
   --   
   For full context, visit https://www.polytechforum.com/electrical   
   pcb-assembly-tutorial-how-to-turn-pcb-into-pcba-step-by-ste-1565274-.htm   
      
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