man with drill
To generate a modern printed circuit board (PCB) for items as varied as mobile phones and vehicle dashboard components, many types of PCB assembly equipment are required. Typical equipment consists of wire and solder paste connectors, pick and place devices, reflow ovens, and optical inspection machines. In addition, the PCB assembly kit also includes a test engine to ensure that each board works properly.
A solder paste and wire binding machine creates the solder pads along the surface of the printed circuit board. The wire mesh is cut in a specific pattern for the pads and placed on a blank PCB; The solder paste is forced through the open mesh holes in the surface of the board. The resulting pattern of solder paste on the PCB creates the necessary circuitry for future placement of electronic components.
Pick-and-place PCB assembly equipment can be described as automated hands that locate and place tiny electronic components, such as resistors, from a stack of supplies onto solder plates. Previously, workers performed this part of the assembly manually, but newer components are extremely small and more difficult to fit. This specialized type of PCB assembly equipment ensures that the correct component is placed in a particular orientation for the circuit to work properly.
Electronic components are temporarily held in place by solder paste; however, they must be permanently soldered to the printed circuit board by entering a reflow oven. This extremely hot oven allows the components to adhere to the plates by fusion welding. Heat is controlled within a specific range to ensure consistent solder flow while maintaining the structural integrity of each component.
As soon as the plate comes out of the reflow oven, it must be inspected by an optical machine. The components are extremely small; any defects or partial welding points cannot be seen with the human eye. A worker places the board through this specialized optical PCB assembly machine. Light reflects off components and circuits on the board and bounces off various sensors; these sensors can detect the slightest break in the circuit or an incompatible component. Any problem is reported through the machine screen for immediate repair or rebuild.
The final form of PCB assembly equipment that the board must go through is a test module. Each PCB manufacturer has a different testing process depending on the intended use of the board. Typically, an employee will place the plate in the test equipment and apply electrical power. It will be necessary to check the activation and deactivation of each function of the board, as well as the reliability.