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Factors affecting the placement bias of PCB components

Factors affecting the placement bias of PCB components

The mounting accuracy of SMD on the PCB depends on many factors, including PCB design and processing, SMD package form, positioning deviation of the placement machine drive system, etc. The former involves the quality control of device entry inspection and PCB design and manufacturing, the latter Obviously related to the performance of the placement machine.
Since the position of the components stored in the feeder position is not accurately defined, and the geometrical dimensions of the components are inconsistent, after the suction nozzle holds the components, the center of the component is deviated from the axis of the vacuum nozzle, if not aligned. Calibration, it is bound to be
Device placement accuracy has an impact.

PCB components
The design limitations of the mechanical structure of the placement head make the movement of the vacuum nozzle in the Z-axis direction generally imperfect, and the movement stroke is slightly tilted or rotated, so that the tip end of the nozzle cannot be completely perpendicular to the mounting surface of the printed board. At this time, the error of the Z-axis stroke must be accurately calibrated to correct the X, Y, and θ-axis drive servo systems.
The orientation of the components in the feeder bin is often not the direction required for placement, so after the components are held, the true
The air nozzle has a rotating action with the components, and the center of the component coincides with the center of the nozzle rotating shaft is random. Therefore, it is necessary to measure the deviation value of the X, Y, θ axis of the component and the center of the nozzle rotation axis, or accurately align the intersection point of the nozzle rotation axis with the PCB mounting surface to ensure the placement position and arrangement direction parameters of the component. Make corrections.

Mar-18-2019

FASTPCBA