FAQ
Titanium AM FAQ: TC4, RFQ, tolerances, CT, and traceability
Practical answers for engineers and procurement teams preparing TC4, Ti-6Al-4V, TA1, TA2, CP titanium, LPBF, or EBM RFQs.
Frequently asked questions
What information must be included in a titanium AM RFQ?
Include alloy grade and standard, process preference, quantity and lot definition, STEP files, drawings with datums, critical tolerances, functional surfaces, post-processing, inspection scope, documentation level, Incoterms, and ship-to country.
How do I decide whether LPBF, EBM, or DED is right?
LPBF is usually used for fine features and tighter geometric control. EBM can fit thicker sections and hot powder-bed process needs. DED is usually for larger near-net parts, repair, or deposition where machining is expected.
What is the practical difference between prototype and production titanium AM?
Prototype work usually has limited statistical evidence. Production requires locked parameters, powder and build-lot controls, repeatable post-processing, and stable acceptance criteria tied to part class.
What drives titanium AM cost more than part volume?
Support strategy, build height, orientation, powder evacuation, HIP or heat treatment, machining access, CMM/CT scope, and traceability documentation often drive cost more than raw part volume.
What tolerances are realistic before machining?
As-printed tolerance is geometry and datum dependent. Critical interfaces should usually include machining stock and stable datums. Tight all-over tolerance without machining access is expensive and risky.
When is titanium AM not a fit?
It is usually not a fit for simple geometry, high-volume cost sensitivity, tight all-over tolerances with no finishing access, inaccessible trapped powder, or high fatigue/leak demands without an evidence budget.
What titanium alloys and material names are most common in AM?
Ti-6Al-4V, Grade 5, TC4, and Ti64 identify a broad alloy family, not automatically the same purchase specification. ELI/Grade 23 and commercially pure grades need separate review. State the exact standard, revision, chemistry, AM route, condition, and acceptance requirements; TA1, TA2, and CP Ti Grades 1-4 are not interchangeable grade names.
What is the difference between Grade 5 and Grade 23 ELI?
ELI means extra-low interstitials. Compare the chemistry and property requirements in the applicable Grade 23 and Grade 5 specifications for the same product form and condition. ELI is not an automatic upgrade, a fatigue guarantee, or approval for an implant or flight part.
Why does oxygen control matter for titanium powder?
Titanium is reactive. Oxygen, nitrogen, and hydrogen affect strength, ductility, and fatigue. Powder reuse and handling should be controlled and traceable for higher-risk parts.
How should internal channels be designed?
Prioritize depowdering and inspection. Include access ports, avoid dead ends, reduce sudden section changes, and define flow, roughness, blockage, CT, or pressure-drop criteria when channels are functional.
Can titanium AM produce leak-tight manifolds?
Leak-tightness depends on porosity control, surface closure, HIP when justified, interface design, and validation. Specify leak rate, test method, pressure differential, and whether internal surfaces can be treated.
What is the right approach for threads and precision holes?
Specify the final thread or bore, datum, fit, surface condition, and gauge or inspection method. A printed pilot with machining stock may be suitable, but the supplier must confirm access, stock allowance, distortion, and machining sequence. Accept an as-built feature only against an agreed functional and inspection requirement.
Why is stress relief commonly required?
LPBF introduces residual stress from steep thermal gradients. Stress relief reduces distortion risk during support removal and machining and is often the minimum stability step.
When is HIP necessary?
HIP is used when internal porosity reduction matters for fatigue, fracture-critical, or leak-critical applications. It is not always needed for non-critical prototypes.
Does HIP eliminate all defects?
No. HIP can close certain pores, but it does not correct geometry or reliably fix every lack-of-fusion or surface-connected defect. It must be combined with design, process control, and inspection.
What inspection methods are most useful?
CMM assesses dimensions against the agreed datum system; CT can assess accessible internal features within a qualified scan capability; surface measurements and representative coupons address different requirements. Select methods by failure risk and acceptance criteria, not as a universal test bundle.
What can CT prove and not prove?
CT can reveal certain internal features and imperfections, but voxel size alone does not establish detectability. Geometry, material thickness, contrast, scan setup, reconstruction, and analysis affect the result. Agree demonstrated detection capability and acceptance criteria; CT does not prove the absence of every defect or replace a functional leak test.
Do I need tensile coupons for every build?
High-risk or production-intent parts may require coupons per build lot or defined frequency. For prototypes, coupons may be optional unless mechanical properties gate acceptance.
What does traceability mean in practice?
Traceability links the part to powder lot and reuse state, build file/version, machine and parameter set, build date, post-processing batch, inspection reports, and delivered certificate package.
What documents are commonly included?
The quotation must state the included records. Request a COC, powder COA, dimensional report, post-processing records, build traceability, CT or coupon results where needed, with the applicable lot and part references. Do not assume a test or document is included unless it is agreed in the delivered scope.
What is the difference between print-only and delivered functional part pricing?
Print-only covers build and basic depowdering. Delivered functional parts include support removal, heat treatment, HIP if needed, machining, finishing, inspection, and documentation.
How do I compare quotes across suppliers fairly?
Compare the same alloy, process, post-processing, machining, inspection scope, documentation package, Incoterms, and delivery assumptions. Many low quotes exclude acceptance evidence.
Can you handle sensitive projects?
We can discuss NDA and data-handling expectations. Do not send export-controlled, classified, or restricted files unless a suitable agreement and handling process are already in place.
What is the cleanest quote email template?
Use the RFQ page format: alloy, process, quantity, STEP plus drawing, datums, critical tolerances, post-processing, surface finish, inspection scope, documentation package, ship-to country, and target date.
Need a quote with feasibility notes?
Send STEP, drawings, alloy target, quantity, lead time, critical dimensions, datum scheme, post-processing, and inspection requirements.