TH Aspect Ratio (PCB Aspect Ratio)

Reports an aspect ratio for the smallest plated through hole in the layer, calculated as: <drill_span> / (<hole_size> + const).

Internal ERF Name	th_aspect_ratio
Measurement Shape Measurement ID Measurement Value	Smallest TH drill in the layer Pad (representing a drill), drill size, drill span Ratio (floating point number)
Layers Displayed	Drill layer
Graphic
Purpose	Aspect ratio is a fabrication term used to describe the relationship between drill span and the drilled hole diameter. Holes that are too small for their length cannot be successfully plated.
Function	Reports an aspect ratio for the smallest plated through hole in the layer, calculated as: <drill_span> / (<hole_size> + const) <drill_span> — determined by ERF variable v_pcb_aspect_ratio_correction. <hole_size> — Size of the smallest plated through hole in the layer (diameter for circular pads or diagonal of the bounding box for non-circular pads). Plated slots are ignored. const — Correction constant determined by ERF variable v_pcb_aspect_ratio_correction. If v_aspect_ratio_calc_drill_span = 0 and attribute Thickness does not exist, or its value is zero or a negative number, a very large value (10000) is reported to the relevant categories to indicate a critical problem. A message is printed to the log.
ERF Parameters	pp_drill_layer
ERF Variables	v_pcb_aspect_ratio_correction v_aspect_ratio_by_finished_size v_aspect_ratio_calc_drill_span
Limitations