Numbering the Design Tree to Keep Symmetric Frames Straight
Equipment mounting frames and bracket assemblies are large and stand in place waiting for inspection. They carry many kinds of attached components in a complex spatial layout, and externally visible errors such as a missing part, a wrong part, a reversed part or an obviously displaced part affect subsequent equipment installation. The old routine had an inspector with drawings threading between frames, checking items one at a time. Many components, scattered positions, heavy workload, inconsistent records, and a standard that varied with the person.
The difficulty on frames is repeated features
Many component types and strong structural repetition mean similar features are easily mistaken for one another in an overlay. That is the main threat to accuracy, and it does not fade with experience: two identical brackets in symmetric positions look almost the same, and telling them apart from memory eventually fails. On a frame, the mistake is not seeing nothing; it is confidently checking the wrong one.
The design tree is the error-proof index
The scheme relies on the structured expression of the design CAD to distinguish component types and mounting positions. Because the frame repeats symmetrically, similar features are confirmed one by one using design-tree numbers as the index, so the check order is fixed instead of following whatever the eye reaches next. That prevents skipped items, and the tablet's depth sensor keeps the overlay stable, lowering the chance of checking the wrong location. Progress is visible on the tablet, so the inspector knows exactly where the walk stands.
Overlay and record on the same tablet
A problem found during the check is marked on the tablet, and the position and image evidence are saved at the same time. The record archives with the check result and an electronic report is generated at the end. The overlay updates with the viewing angle, so the inspector does not realign at every frame.
Checking and recording as one step means no back-filling afterwards, which often matters more to shop-floor acceptance than the overlay itself. A scheme that doubles the paperwork gets used for a week and then abandoned.
600 seconds per unit on the floor
A check takes about 600 seconds and produces an archived report, subject to site acceptance results. The device is a tablet with a LiDAR depth sensor, and the inspector walks around the frames and brackets; nothing has to be moved to a dedicated inspection area. Compared with image-only checking, the overlay shows design basis against the real part directly, so the conclusion can be verified and queried on the spot, with the whole check recorded.
The loop beyond the report
Anomalies are handled before release, the rework recheck also happens on the tablet, and reports export by check item and exception photo for the quality department to archive. Selection should weigh overlay stability, ease of recording and report export. The value is not single-check speed but fixing three things at once: design basis, check order and record format. Once those are fixed, the result stops depending on how sharp the inspector feels that day.
Points raised walking the frames
How are symmetric components prevented from being confused?
By confirming each item against its design-tree number in a fixed order, with progress visible on the tablet.
Are checking and recording two steps?
No. Marking a problem saves its position and image immediately, and the electronic report is generated at the end.
Why does the check travel to the part?
Frame assemblies are hard to move. Checking where they stand removes the transfer to a dedicated area.
How does this differ from photo-based inspection?
A photograph leaves only an image; the AR overlay puts design basis next to the real part, so the conclusion can be verified on the spot.