No single inspection method proves everything on a repaired part. Visual checks, dimensional inspection, penetrant or magnetic testing, ultrasonic methods, CT, hardness checks, and metallographic cross-sections each answer different questions. A good repair release plan matches the method to the defect risk instead of asking for a long generic list. For repairs carried out by LMD, DED, or Laserauftragschweißen, that distinction matters because the process route, substrate, and rebuilt geometry each create different inspection questions.
Inspection planning belongs in the RFQ
Inspection should be discussed before the repair starts, not after the part is already deposited and machined. Buyers need to define which zones are critical, which failure modes matter, and what evidence is required for release. If that is left vague, the project often ends up with either too little proof or expensive testing that does not answer the real acceptance question.
What each inspection method actually proves
| Method | Best for | Main limit |
|---|---|---|
| Visual inspection | Surface condition, obvious defects, repair coverage | Cannot prove internal soundness |
| Dimensional inspection / CMM | Geometry, stock allowance, final dimensions | Does not prove bond quality or internal integrity |
| PT or MT | Surface-breaking crack detection on suitable materials and surfaces | Limited to specific defect types and access conditions |
| UT | Internal discontinuities in some geometries and materials | Interpretation depends on geometry, calibration, and access |
| CT | Internal features or defect questions that need volumetric evidence | Often more expensive than other methods and not necessary for every job |
| Metallographic cross-section + microscopy | Interface, dilution, microstructure, HAZ, defect characterization | Usually destructive and therefore scope-dependent |
| Hardness checks | Local hardness and transition behavior | Does not prove overall fitness for service on its own |
Build the stack from the risk, not from the method names
If the main risk is surface cracking after a rebuild, the inspection plan should prioritize methods that answer that question. If the main risk is internal lack of fusion or a geometry-sensitive internal zone, the plan may look very different. The best inspection stack is therefore the one that proves the failure modes that matter for the part in service.
That is also why industrial repairs should separate three categories clearly: surface condition, internal integrity, and final geometry. Many inspection misunderstandings happen because the buyer asks one method to prove all three.
Public proof: valve seat ring coating and surface-crack risk
Exafuse has publicly shown a valve seat ring laser cladding workflow with preheating and a hard wear-resistant coating route. That proof story belongs in inspection discussions because hard coatings often make surface crack risk, heat management, final geometry and finish quality part of the release decision.
For a valve seat ring or similar hard coating, an inspection stack may need to answer whether the final seating surface is geometrically correct, whether surface-breaking cracks are acceptable or absent by the agreed method, and whether bond or microstructure evidence is required. The exact stack depends on the part and acceptance criteria.
Public proof: forging hammer repair and impact release risk
Exafuse has publicly described LMD-enhanced forging hammer work for high-impact wear zones. Inspection planning matters because the release question is not only whether material was deposited. It is whether the rebuilt working surface, interface condition, crack condition, final geometry and documentation are sufficient for the next service cycle.
In-house capability versus external inspection route
The confirmed approved claim for Exafuse is in-house microscopy and metallographic preparation capability. That supports cross-section review and microstructure-related evaluation when it is part of the agreed scope. Methods such as CT, UT, PT/MT, or CMM should be described as part of a possible inspection plan only when the delivery route is clearly defined, whether in-house or through external partners.
The important point for buyers is not where every test sits physically. The important point is that responsibilities, methods, and documentation are agreed before the repair starts.
Documentation should follow the release decision
The documentation package should support acceptance of the repaired part. That may include dimensional results, photographs, inspection records, metallographic evidence where relevant, and notes on any deviation handling. A generic pile of reports is less useful than a compact package tied directly to the release criteria.
What buyers should send for inspection alignment
Send the drawing or CAD if available, identify the critical zones, state the suspected or known damage mode, and define which defects are unacceptable in service. For hard coating or valve-seat work, include the required final seating surface, whether crack inspection is mandatory, and whether hardness or metallographic evidence is expected. For forging hammers and impact tooling, include the working face, impact duty, previous repair history and whether surface crack checks are part of release. Also include any mandatory customer standards, documentation requirements, and whether external laboratory or NDT support is already expected. That makes the inspection discussion practical instead of theoretical.