How to evaluate Holle Registration Accuracy in PCB drill
2018-11-26 16:21Writer: qyadminReading:
For the hole registration accuracy evaluation, the displacement of the drilled hole from the target is measured.All holes are measured using a PWB hole tester (AOI machine).All the holes are measured for each drill bit used.The exit side of the bottom panel is measured for the hole registration accuracy when stack drilling is carried out.The centroid method, shown below, is used.The measurement data is analyzed by "Maximum displacement (Max)", "Average value + 3s, (Ave+3s)", and "Cpk value", etc.In "Average value + 3s", "s" means standard deviation value.Centroid MethodTo counterbalance the amount of displacement caused by external factors of the drilling machine's registration accuracy, the center of the data group of the displaced drilled holes is set to origin (0,0) as shown in the figure below. The evaluation is carried out using the centroid method.L:The center displacement of the group data due to external factors.
Raw Data Hole Distribution Chart
Centroid Data Hole Distribution Chart