If your inspection plan names a single method for the whole part, either a 3D scan or a CMM, you may be leaving critical features without usable evidence. Neither approach is better in general. A scan can document an exterior surface well while a deep or occluded bearing seat goes unmeasured. A CMM can verify a bore's diameter and position with a few points and say nothing about the form between them.
The two work differently. KEYENCE, which makes both, describes a CMM as taking points one at a time with a touch probe, and a scanner as collecting a non-contact point cloud of up to millions of points. In its account, a CMM's limited points allow more accurate results on basic dimensions. Scanning captures complex surfaces more fully, but the point cloud has to be processed before measurements can be taken. That processing step matters for evidence. With a scan, the choices made afterward, such as which points are kept and how features are fitted, become part of the result. These are one supplier's general statements, not an uncertainty for your part.
The article's advice is to decide feature by feature. For each critical feature on the drawing, such as a bore, a bearing seat, a bolt-hole pattern or a datum surface, confirm these points:
Access: can a probe reach it, or can the scanner see it?
Surface response: has the provider shown the method works on this finish?
Datum alignment: will the part be aligned to the drawing's datums, or fitted by best fit?
Feature extraction: how is the feature derived from the points, and with what settings?
Demonstrated uncertainty for this feature type under these conditions.
Coverage: which regions will be measured, and which won't?
Dense scan points don't prove a result is fit for the decision, and a "CMM" label doesn't either. A sensible plan may combine both, for example contact probing for datums and holes and scanning for a complex exterior surface. It should then tie the two data sets to the same datum frame and name any region left unmeasured.
For the full planning table and measurement-plan checklist, read: 3D Scanning vs CMM Inspection: Choose by the Feature to Verify
For a part-specific inquiry, the public product family is here:
https://www.kensetsu-buhin.com/collections/excavator-undercarriage-parts
Send the drawing, the critical features, and the evidence you already hold. Then ask what documentation is available. A plan is complete when every critical feature has a method and a demonstrated basis, the data sets share a datum frame, and the unmeasured regions are named.
