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Printed circuit board equipment involves many different types of machines, including solder paste devices, pick and place machinery, reflow ovens, and optical bond testers. The final printed circuit board (PCB) product also needs to be tested; workers will commonly place the board on a proprietary testing jig so that it can be powered up and allowed to perform all necessary functions. Each machine must be properly adjusted and maintained for accurate PCB production.
Blank PCBs need to have circuit pathways adhered to their surfaces before any electronic components can be added. A solder paste machine is a type of printed circuit board equipment that uses a screen printing process; a screen mesh with a particular circuit pattern is placed across the PCB's surface while solder paste is forced through the openings. The paste fastens to the PCB's surface in the shape of the predetermined circuit pathways.
Typically automated, pick and place machines are types of printed circuit board equipment that move electronic components from an inventory supply and onto the PCB's surface. Specifically, the machine chooses the correct component from the supply and orients it to fit directly onto the solder paste pads created by the previous machine. It is imperative for the components to be placed in the proper position or the circuit will not work correctly; in fact, the board may be damaged beyond repair if components are positioned backward and power is applied.
One of the most important pieces of printed circuit board equipment is the reflow oven. This specialized heating device is set for a specific temperature range to melt the solder paste on the PCB. The melting process must be accurately controlled so that the solder and flux mixture adheres to the attached components, but does not harm the circuit pathways or electronic parts. An engineer must determine the correct temperature range based on the components' sensitivity and the solder paste mixture ratio.
The final PCB must still be examined by an optical bond tester. Many circuit pathways can have tiny cracks from the heating process that can affect the board's overall functionality; the optical tester is a type of printed circuit board equipment that will pinpoint cracks and breaks within the circuitry that cannot be seen with the human eye. Any defects found must be repaired or scrapped as waste.
If the board passes the optical test, a worker normally tests the board in a real life application. A proprietary simulation tester can be attached to the PCB so that each button or switch is tested. Only boards that pass all tests will be allowed to be sold or distributed by the business.
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