label: customer pcb,printed circuit board,Applications Of PCB
The typical manufacturing process for pagers involves two distinct steps. These steps are known as the "front end process" and the "back end process." Both processes utilize computer integrated manufacturing, pcb or CIM. CIM is a network of physical hardware linked with computers using special software, or programs pcb. CIM is designed to assist the production operators in tracking each stage of the manufacturing process and ensuring that the pager is built with the proper components and options specified by the customer pcb.
A group, or array, of one or more receiver or decoder printed circuit boards is run through a machine called a solder printer. Printed circuit boards (PCB) are thin, stiff pieces of electrically non-conducting material onto which a pattern of electrically-conducting material has been bonded to form numerous circuit paths, much like flat wires. Electronic components are attached to both sides of the board and interconnected by the printed circuitry. The solder printer is programmed to apply a small amount of solder paste to the points where the components will make electrical contact with the printed circuits.
The pcb are then processed through another machine known as a high-speed chip shooter. The shooter quickly and accurately places, or shoots, the majority of the pager's small components onto each board.
After a visual inspection, the pcb are run through a series of robotic placement machines which place the larger and odd-shaped parts onto the pcb boards. These include the integrated circuit (IC) chips, oscillators, and crystal filters.
Once all these parts have been placed, the boards are run through a reflow oven. In this oven, the solder paste melts, or reflows, to form an electrical connection between the components and the printed circuits.
The board arrays are then given a final visual inspection for defects and are sent through the singulation process in which the individual boards are cut from the array and labeled.
Some pagers require parts which must be placed by hand in a process called "post reflow assembly." These parts are generally too large for robotic placement or too sensitive to the extreme heat of the reflow oven. The liquid crystal display (LCD) is attached to the decoder board, and the decoder board with the LCD is placed pcb into the plastic outer housing. The housing also contains the on-off switch, belt fastener clip, and battery compartment with electrical contacts. At this point, the pagers have none of their specific features. They have not been assigned a radio frequency, nor have they been programmed with a unique telephone number or any customer options. All of that will happen in the back end process.
