Diagnosing a Drill File That Is Scaled or Misaligned

If holes appear far from their pads in a fabrication viewer, do not immediately translate or scale the drill file by eye. The mismatch may come from an export or import setting. Resolve the coordinate interpretation so the corrected package remains reproducible.

Read the export settings and file header

KiCad’s command-line documentation exposes distinct drill-output controls for units, coordinate-zero format, origin, mirroring, and oval-hole representation. These are separate settings, not interchangeable ways to fix the same problem. Other CAD tools have corresponding controls that should be checked against their own documentation. KiCad: drill export options.

Record the CAD version and saved export configuration. Inspect the drill file’s declared units and coordinate format where present. Confirm that the viewer has interpreted the header rather than relying on a remembered default. A file with omitted or ambiguous information may require the explicit import settings agreed with the fabricator.

Classify the visible mismatch

• A uniform displacement suggests comparing origins and offsets.
• A consistent scale difference suggests checking units or coordinate interpretation.
• A reflected pattern suggests reviewing mirroring and view orientation.
• Only some missing features suggests checking tools, slots, and separate hole-span files.
• Correct centers with incorrect sizes suggests reviewing tool definitions and units.

These patterns guide investigation; they are not proof of a unique cause. Use known board dimensions and several widely separated pad centers to test the interpretation. One matching hole cannot establish alignment across the whole board.

Regenerate a consistent set

Compare the copper, profile, and drill origins in the CAD output settings. Correct the source configuration and export again into a clean revision-specific directory. Avoid leaving both old and new drill files in the delivery archive. If plated and non-plated holes are separate, verify each file independently and together.

For example, a drill map PDF may align correctly while the machine-readable drill data do not. The map is useful evidence of intent, but it does not repair the CNC data. Inspect the actual files that manufacturing will consume.

Confirm with an independent view

Load the regenerated package into a viewer and check overall dimensions, tool sizes, slots, and alignment at multiple locations. Ask the fabricator to confirm the interpretation if its system uses different import conventions. Preserve the working settings with the project so a later export does not reintroduce the same ambiguity. The goal is a correctly defined coordinate system, not a visually convincing manual adjustment that nobody can reproduce.