The current development of science and technology has promoted the continuous innovation of PCB. PCB puzzle is actually a combination of several PCB unit boards using various possible connection methods. Normally, when a hardware designer designs a PCB, he considers the arrangement of electrical signals and components on the circuit board, and focuses on the functional issues of the product. Less consideration is given to PCB manufacturing and assembly. To realize the smooth manufacturing of PCB, especially the SMT assembly, it is necessary to pay special attention to the PCB design. Next, we will introduce 10 tips for PCB panel。
1) The outer frame (Board edges) of the PCB should adopt a closed-loop design to ensure that the PCB panel will not be deformed after being fixed on the fixture.
2) PCB panel width ≤260mm (SIEMENS line) or ≤300mm (FUJI line); if automatic dispensing is required, PCB panel width × length ≤ 125 mm × 180 mm.
3) The shape of the PCB panel is as close to a square as possible. It is recommended to use 2×2, 3×3... ;
4) The center distance between the small units is controlled between 75mm and 145mm.
5) When setting the reference mark point, usually leave a non-resistance area 1.5mm larger than it around the mark point.
6) There should be no large devices or protruding devices near the connection point between the outer frame of the board and the inner unit board, there should be a space greater than 0.5mm between the components and the edge of the PCB. To ensure the working of the cutting tool.
7) Four tooling holes are made at the four corners of the outer frame , Hole size is diameter of 4mm±0.01mm. The strength of the hole should be moderate to ensure that it will not break during the panel moving. The hole diameter and position need high accuracy,And the hole wall should be smooth and no burrs.
8) Each small board in the PCB panel must have at least three positioning holes, 3≤aperture≤6mm, and no wiring or patching is allowed within 1mm of the edge positioning hole.
9) The reference symbol used for the positioning of the whole board of the PCB and the positioning of fine-pitch devices. In principle, the QFP with a pitch less than 0.665mm should be set at its diagonal position. The positioning reference symbols used for the imposition PCB sub-boards should be used in pairs and arranged at the opposite corners of the positioning elements.
10) Mark point or positioning holes should be reserved for large components, such as I/O interface, microphone, battery interface, micro switch, earphone interface, motor, etc.