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A PCB circuit board design mainly includes the steps of clarifying product requirements, hardware system design, device selection, PCB drawing, PCB production proofing, welding and debugging. So what are the points to pay attention to in these steps?
At the beginning of a hardware design, the first thing to do is to clarify the requirements of the product, which mainly includes clarifying the functional requirements and appearance. The main functions need to be clarified, and a small amount of additional functions can be added later, but the main functions of the product should not be affected. The determination of the product shape is very important, which will affect the later PCB circuit board drawing and component selection.
In hardware system design, the power supply mode, sensor type, communication mode, human-computer interaction mode, reserved interface, etc. of the product should be determined according to the functional requirements of the product. Generally, Visio can be used to draw the block diagram of the system. The block diagram of the system should be able to describe the relationship between the various module circuits of the hardware system and the module components of the entire system.
At the stage of device selection, you need to select related devices according to your own product functions, which generally include the selection of chips for power supply, main control, sensors, communications, and storage. The selection needs to consider the function, price, supply and other factors of the chip to choose a chip suitable for your product. Chip selection channels can be compared through large-scale chip electronic component malls such as Lichuang Mall, Yunhanxincheng, and Dejie Electronics.
PCB drawing involves the EDA software of PCB design. At present, the mainstream PCB design tool software used by engineers and technicians engaged in circuit design in China are Allegro, PADS and Altium Designer. Beginners recommend using Altium Designer, there will be more tutorials online.
After the PCB is designed, you can go to the PCB manufacturer for proofing. Before production, you need to provide the manufacturer with production documents. One is to directly provide the PCB file. This method will risk the product being leaked. It is recommended to go to large manufacturers for proofing to avoid abnormal debugging after PCB production problems. This situation will make you doubt life later.
After the PCB and components are in place, you can solder. The necessary tools for soldering: soldering iron and air gun. As for the tweezers, it depends on the technology. Welding is generally divided into direct manual welding and brushed steel mesh welding. Direct welding tests the craftsmanship, and the welding is not good. If you brush the stencil welding, you can place the stencil order together when you produce the PCB. Generally, a stencil is 50. After brushing the solder paste with the stencil, if possible, mount the chip on the machine, if not, just swing it. It can be baked in a reflow oven or blown with an air gun.