Hole Registration Accuracy

Hole Registration Accuracy Test

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 Method
To 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.

Raw Data Hole Distribution Chart	Centroid Data Hole Distribution Chart
L: The center displacement of the group data due to external factors.

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