1. What is Mark Points
The Mark point is the position identification point used by the PCB on the automatic placement machine in the circuit board design. Mark point can be bare copper, bare copper protected by a clear anti-oxidation coating. The PCB board Mark point is also called the reference point, which provides a common measurable point for all steps in the surface mount process, ensuring that the SMT equipment can accurately locate the PCB board components. Therefore, the Mark point is very important for SMT production.
2. The importance of Mark points
The mark point is the point used for positioning when using machine welding. The PCB of surface mount components needs to set the mark point, because in the mass production of the SMT placement factory, the placement machine is manually or automatically by the operator to find the mark point for calibration. The selection of Mark points directly affects the placement efficiency of the automatic placement machine.
Mark points can be divided into single board mark points, panel mark points and local mark points. Mark points on a single board can locate the positions of all circuit features; on the panel, they can assist in locating the positions of all circuit features; local Mark points can locate the fiducial mark of a single component to improve placement accuracy.Like QFP, CSP, BGA,those important components must have local Mark.
1. In order to solve the problem that the placement machine correctly mounts the components on the PCB, and makes the precise positioning point on the PCB, the optical components of the placement machine pass through these two Points identification judges the specific position of the PCB board, usually a PCB has at least two BOC marks.
2. The identification point is used to locate the moving placement machine. In fact, it is a single-layer special pad, which is generally placed on the diagonal (asymmetric) of each side of the PCB. It requires a certain size, and no devices can be placed around it, so as to contrast with the background and facilitate machine identification.