The size and shape of SMT circuit board shall meet the requirements. Size and structure shape, location of mounting hole, size of hole diameter, layout of power supply, connector, switch, potentiometer, LED or LCD, position, size and edge size of heat sink meet the requirements.
Is the processing form and process design of SMT chip reasonable
On the premise that SMT circuit board design meets the requirements of whole mechanical and electrical performance, mechanical structure and reliability, the following aspects should be considered in order to reduce cost and improve assembly quality.
Minimize the number of PCB layers. It can use single-sided PCB board without double-sided PCB board, and can use double-sided PCB board without multi-layer board, so as to reduce PCB processing cost as much as possible. The reflow welding process should be adopted as much as possible, because reflow welding has more advantages than wave soldering.
Minimize the process of PCB assembly process, and try to use cleaning free process.
Whether it meets the requirements of SMT equipment for PCB design
Whether the shape and size of PCB are correct, and whether the splicing process is considered for small size PCB;
Whether the clamping edge design is correct;
Whether the design of positioning hole is correct;
Whether the positioning hole and non grounding installation hole indicate non metallization
Whether the mark figure and its position meet the requirements, and whether 1-1.5mm solder free area is reserved around the mark figure;
Whether environmental protection requirements are considered.
Whether it meets the requirements of SMT process for PCB design
Whether the selection of substrate materials, components and packaging of components meet the requirements.
Whether PCB pad structure (shape, size, spacing) conforms to DFM specification;
Whether the width, shape and spacing of the lead wire and the connection between the lead wire and the pad meet the requirements;
Whether the overall layout of components and the minimum distance between components meet the requirements, whether the repair dimension is considered around the large components, and whether the polarity arrangement direction of components is consistent as far as possible;
Whether the arrangement direction of reflow welding surface and wave soldering surface components meets the requirements;
Whether the aperture and pad design of plug-in components meet the DFM specification;
Whether the patterns of solder mask and wire mesh are correct, and whether the polarity of components and the first leg of IC are marked;
Whether the span of the axial component plug-in hole is appropriate (or whether the component forming is correct), and whether the span of the radial component plug-in hole is consistent with the pin center distance or the component forming size.
Whether the distance between adjacent plug-in elements is conducive to manual plug-in operation;
Whether the position of the connector on the PCB is conducive to wiring and plugging.