Pick-and-Place Files: Review Origin, Side and Rotation

Check placement data against a visible assembly reference before production. The coordinate file needs an agreed origin, units, board side and orientation convention.

Begin with a reference view

A placement file contains instructions that must agree with a physical board. Pair it with an assembly drawing that identifies the board revision, viewing direction, polarity and pin-one indicators. A numeric rotation is difficult to review when the zero-degree orientation of the footprint is unknown.

Show recognizable features such as connectors, mounting holes and an asymmetric component. These provide a practical way to identify a mirrored or rotated interpretation before the placement program is used.

Check coordinate assumptions

• State the units explicitly and confirm the exported values use them.
• Identify the placement origin on the drawing.
• Confirm whether positions describe an individual board or an assembly panel.
• Document how top and bottom sides are represented.
• Explain any manually placed components omitted from automated placement data.

Do not move the coordinate origin just to make a spreadsheet look cleaner after export. If a transformation is necessary, record it and compare the result with the original data. Re-exporting from the controlled design is generally easier to trace than editing many coordinates by hand.

Review orientation using actual parts

Select examples with unambiguous orientation: a polarized capacitor, a diode, a keyed connector and an integrated circuit with a pin-one marking. Compare the drawing, footprint and supplied part information. Have the assembler confirm how its placement system interprets those examples.

For instance, a connector can have a mechanically symmetrical outline while its mating orientation is not interchangeable. A placement check based only on the rectangle can therefore miss a functional assembly error.

Cross-check the fitted population

Match reference designators to the released BOM variant. Check for DNP positions, parts supplied as a subassembly and components that require a secondary operation. Every discrepancy should have an explicit disposition rather than being silently removed from one file.

When a BOM change alters the physical package, revisit its placement data and land pattern. Keeping the same circuit function does not guarantee that a replacement component has the same centroid or orientation reference.

Retain first-article evidence

Before a larger run, compare the first assembly against the released drawing and approved orientation examples. Record any placement-program corrections with the board revision. Ensure the corrected program and the released files cannot be confused with earlier versions on the next order.

Use the assembly file guide to prepare the package. A placement file is one part of that handoff; it does not replace the BOM, assembly drawing or acceptance requirements.