Category: Surface Mount
Description: The Solder Paste Inspection (SPI) process measures the volume of the solder pads before the components are applied and the solder melted, to help reduce the incidence of solder-related defects.
Major Cost Drivers -- PCBA Solder Paste Inspection
Solder Paste Inspection Cycle Time is a sum of the time to load the PCBA into the machine from the input conveyor, move the PCB to the lock position in the machine and clamp it down, look at the fiducials on the PCB, move the inspection laser across the PCB, and unload the PCB from the machine and output rail..
Process Time = Load Time + Fiducial Check Time +
Solder Paste Inspection Time + Unload Time
- // Load into Machine. Input Conveyor time captured by Screen Printing Output Conveyor.
- Load Time = (Machine variable)
- Machine Load Time = (Machine variable)
- // Time to look at alignment fiducials.
- Fiducial Check Time = (Machine variable)
- // Time to move laser across PCB and take measurements for SPI.
- Solder Paste Inspection Time = PCB Area/Scanning Speed
- PCB Area = PCB Width * PCB Length
- PCB Width = (Global Input)
- PCB Length = (Global Input)
- Scanning Speed = (Machine variable)
- Solder Paste Inspection Time = PCB Area/Scanning Speed
- // Unload and Conveyor after Solder Paste Inspection.
- Unload Time = Output Conveyor Length/Output Conveyor Speed + Machine Unload Time
- Machine Unload Time = (Machine variable)
- Output Conveyor Speed = (Machine variable)
- Output Conveyor Length = (Machine variable)
- Unload Time = Output Conveyor Length/Output Conveyor Speed + Machine Unload Time
User Inputs –- PCBA Solder Paste Inspection
None process-specific.
Global Inputs: PCB Width, PCB Length