The short answer
On tall SLM RFQs, **recoater clearance** is not the same note as **build orientation** or “print standing up.” The recoater blade or roller has to pass over each layer; a tall, thin, or poorly supported wall can deflect, catch, or stop the job. Silence on maximum height in the build, on whether a slight lean or a sacrificial rib is allowed, and on what happens if the recoater contacts the part, is what widens many [quote-new.php](https://3dwk.com/quote-new.php) **rates.v1.1** / powder estimate bands—not the cubic centimeters of Ti-6Al-4V alone.
This guide is for buyers packaging titanium RFQs where CAD shows a 120–200 mm tall bracket with no recoater note, or a notes cloud that says “orient as needed.” Illustrations use an **Example part** only—not a customer flight fitting. Sibling notes live in [SLM build orientation notes for buyers](https://3dwk.com/resources/slm-build-orientation-notes-for-buyers) and [support-strategy notes for SLM thin walls](https://3dwk.com/resources/support-strategy-notes-slm-thin-walls); here we focus on **recoater-clearance packaging** so estimators do not guess a risky tall-Z orientation or an unplanned stop.
What recoater clearance means for quoting
**Recoater clearance** is the planned gap and stiffness path that lets the powder-spreading mechanism travel without colliding with up-facing features, warped overhangs, or a tall wall that grew out of tolerance. **Build orientation** still matters—it sets which face is down, where supports land, and how tall the job is—but orientation without a clearance note leaves the shop to choose a short-Z nest that may not match your datum scheme. Process pages for aerospace titanium ([SLM Ti-6Al-4V aerospace](https://3dwk.com/en/slm/ti-6al-4v/aerospace.html), [SLM Ti-6Al-4V](https://3dwk.com/en/slm/ti-6al-4v.html), [CNC 3-axis Ti-6Al-4V aerospace](https://3dwk.com/en/cnc-3axis/ti-6al-4v/aerospace.html)) assume height and orientation notes when lots mix short blocks with tall brackets.
Do not bury “print as CAD” inside a notes cloud. Put **MAX BUILD HEIGHT 140 MM, RECOATER ALONG X, SACRIFICIAL RIB ON FACE B ALLOWED, STOP-AND-RECOVER NOT ACCEPTABLE WITHOUT BUYER NOTE** on the PDF and mirror it in RFQ text. Background: [DFM checklist before an online CNC quote](https://3dwk.com/resources/dfm-checklist-before-online-cnc-quote) (the same file pack helps SLM buyers), [what files to send for a CNC quote](https://3dwk.com/resources/what-files-to-send-for-cnc-quote).
Height, stiffness, and lean
Tall walls in **Ti-6Al-4V** can grow with a small lean or a thermal curl that is harmless at 40 mm and risky at 140 mm. Calling “as-built height OK” without a maximum Z, a preferred recoater direction, or a permission to add a thin rib that is later removed, leaves the planner to either derate the machine or mark **needs_manual**. If a hybrid CNC skim will clean the datum after cut-off, say so—see [build-plate removal notes for SLM parts](https://3dwk.com/resources/build-plate-removal-notes-slm-parts) and [SLM vs CNC hybrid part strategies](https://3dwk.com/resources/slm-vs-cnc-hybrid-part-strategies). Support removal and skim still belong in their own pack: [SLM support removal and skim notes](https://3dwk.com/resources/slm-support-removal-and-skim-notes).
Ti-6Al-4V powder and machine-time planning bands under **rates.v1.1** sit well above commodity aluminum; height-driven recoater risk is often the quote story, not the kilogram price alone.
When a shorter Z is the real DFM
Use a shorter build (or a split + join) when the tall direction is only a packaging habit and not a functional datum. Use a named tall-Z build when the as-printed grain or support map must stay on a particular face: state **max height**, **recoater axis**, and whether a crash stop is a reject. Promoting every tall CAD model into a “print standing up, no ribs” note over-controls the job and can force a single-part build with a wide risk band. For most aerospace buyers, a **labeled clearance pack** is clearer than “orient for best quality.”
Tolerance and inspection traps
Calling “net shape, no witness,” forbidding any sacrificial rib, mixing a 0.2 mm general profile with a 160 mm unsupported wall, or asking the shop to certify “no recoater marks” on every as-built face without a contact-allowable zone, all force **needs_manual**. Default non-critical faces to a general profile and put functional datums only where a later CNC skim is planned. Related: [powder-reuse notes for SLM buyers](https://3dwk.com/resources/powder-reuse-notes-slm-buyers), [lattice-infill notes for SLM structural parts](https://3dwk.com/resources/lattice-infill-notes-slm-structural-parts), [minimum wall CNC vs SLM](https://3dwk.com/resources/minimum-wall-cnc-vs-slm-for-buyers). Recoater direction belongs next to the height note, not in a separate unmarked email.
Illustration 1 shows an **Example part** tall bracket with a labeled max build height, recoater axis, and an optional sacrificial rib versus a silent tall-Z CAD stance.
Example part walkthrough
**Example part:** Ti-6Al-4V SLM bracket ~40×28×140 mm tall, 2 mm nominal walls, datum A on the cut-off pad, ISO 2768-m equivalent general on non-critical faces. With STEP + **MAX Z 140 MM, RECOATER ALONG X, OPTIONAL RIB ON B (REMOVE AFTER), CUT-OFF STOCK 1.5 MM FOR SKIM, NO UNPLANNED STOP**, expect a usable automatic planning band on [quote-new.php](https://3dwk.com/quote-new.php). Same geometry with silent CAD and “print as oriented, no marks” often lands DFM notes or **needs_manual**—without inventing any customer PO.
Illustration 2 contrasts a vague RFQ (“orient as needed”) versus a labeled recoater-clearance pack and the clearer estimate path.
What widens bands fastest
Unlabeled tall-Z models with thin unsupported walls, a ban on any rib or lean, “no recoater witness” on every face, and powder or reuse rules that are only in a chat thread. Quantity breaks help unit minutes but do not erase a crash-risk orientation—see [how quantity breaks change CNC unit cost](https://3dwk.com/resources/how-quantity-breaks-change-cnc-unit-cost) and [what needs_manual means](https://3dwk.com/resources/what-needs-manual-means-preliminary-quote).
What to do next
Mark **max build height**, recoater direction, and whether a sacrificial rib or planned skim is allowed, then upload on [quote-new.php](https://3dwk.com/quote-new.php). Service pages: [3D printing](https://3dwk.com/3d-printing-service.php), [materials](https://3dwk.com/materials.php). Treat **rates.v1.1** min/mid/max as estimates, not invoices. If the UI shows **needs_manual**, answer the recoater-clearance questions rather than forcing a fake firm price.
Common questions
Is a taller build always more expensive?
Not only because of height under **rates.v1.1** / powder estimates. A 140 mm part that is stiff and well supported can plan cleanly; a 90 mm thin wall that can catch the recoater can be the wider band. Height plus stiffness is the story.
Can I write “orient as needed”?
Only if datums, surfaces, and support keep-outs are truly free. If a later CNC skim or a cosmetic face must stay off the recoater path, write the axis and the keep-out.
When should I add a sacrificial rib?
When a tall wall needs stiffness during the build and you can remove or machine the rib later. Name the rib, the removal method, and whether a witness is allowed.
Does powder reuse change recoater risk?
Reuse policy and recoater clearance are separate packs. State both if they matter; do not assume a reuse note implies a clearance plan.