Checking a PCB STEP Export Before an Enclosure Review

A STEP file can import successfully while omitting the very feature that will collide with the enclosure. Before using it for a mechanical signoff, confirm what the exporter included and whether the component models represent the purchased parts. Treat the exported model as a deliverable that needs its own inspection.

Check export content

Altium’s mechanical-data documentation describes options that affect exported board objects, component bodies, hidden models, and folded rigid-flex state. Those options can change the mechanical assembly presented to another team without changing the electrical design. Use the corresponding settings in the CAD version employed by the project. Altium: mechanical export options.

Record the PCB revision, export settings, model origin, units, and assembly variant. Open the STEP file in the mechanical environment and compare it with the CAD board. Confirm board thickness, profile, cutouts, mounting holes, top and bottom populations, and connector locations.

Inspect the critical component models

• Verify the model against the exact manufacturer package and suffix.
• Check its position, rotation, seating plane, and body height.
• Include connector overhang, latches, and relevant mating geometry.
• Distinguish simplified envelopes from detailed models.
• Identify components with missing or placeholder bodies.

For example, a generic connector block may clear the enclosure wall while the actual latch or cable bend does not. The PCB model should either include those features or clearly identify the additional envelope the mechanical team must reserve.

Review tolerances outside the nominal model

A nominal solid is not a complete tolerance analysis. Include the relevant board-profile tolerance, component position and height variation, fastener clearances, and enclosure tolerances through the mechanical design process. Check installation and service movement as well as the final seated position. A board that fits after assembly may still be impossible to insert through the planned opening.

Keep electrical and mechanical revisions synchronized

When a connector or mounting hole moves, regenerate the export and identify the change. Do not let an older STEP file retain a misleading “final” filename beside a newer fabrication package. Compare revised models using known datums and critical interfaces.

The enclosure review should state which PCB and component-model revisions were checked, what was simplified, and which clearances were evaluated. That record lets a later reviewer distinguish a verified fit from an attractive 3D visualization. A successful import is the beginning of the check, not evidence that the physical product will assemble correctly.

Confirm whether fastening hardware and cable mating parts are included in the model or supplied separately to the mechanical reviewer.