The Mark point, also known as the reference point, provides a common locatable circuit pattern for all steps in the FPC FPCB assembly process. Therefore, FPC FPC board Mark point is very important for SMT production. All SMT patch plates must have Mark points, and the specifications of Mark points are as follows:
1. The shape requires Mark points to be marked as solid circles; A complete Mark point includes a Mark point (or feature point) and an open area. The minimum diameter of Mark marks is 1.0mm and the maximum diameter is 3.0mm. Mark Mark Mark on the same printed board size change can not exceed 25um.
2. Mark point is positioned diagonally relative to the board or combination board and as far apart as possible. Preferably in the longest diagonal position; In order to ensure SMT mounting accuracy, FPC FPC board must have at least one pair of Mark points that meet the design requirements and can be recognized by SMT machine, that is, there must be a single Mark.
3. Mark point (edge) must be at least 5.0mm away from the edge of the printed board (minimum distance required for machine clamping FPC), and must be within the FPC board rather than at the edge of the board, and meet the minimum Mark point clearance requirements. Emphasis: the Mark point edge is more than 5.0mm away from the edge of the plate, not the Mark point center.
4. Around Mark Mark, there must be an open area without other circuit features or marks. The radius of a circle in an open area is greater than or equal to 2R. R is the radius of Mark point. When r reaches 3R, the recognition effect of the machine is better. It is often found that the open area of Mark point is blocked by character layer or CUT by v-cut, which makes SMT machine unable to recognize.
5. The Mark Mark may be bare copper, bare copper, nickel or tin, or solder coating protected by a clear anti-oxidation coating. The surface roughness marked by Mark point should be within 15um. The best performance is achieved when there is a high contrast between the Mark Mark Mark and the substrate material of the printed board. The inner background of all Mark marks must be the same.