The short answer
On a hybrid RFQ, **SLM then CNC skim** and **CNC-only** (or **SLM-only**) are not the same quote package. Hybrid strategies use additive for complex internals or light lattices, then machine datums, seals, and interfaces. Silence on **which faces get skim stock** and **which features stay as-built** is what widens many [quote-new.php](https://3dwk.com/quote-new.php) **rates.v1.1** estimate bands—not the alloy name alone.
This guide is for buyers packaging Ti-6Al-4V or AlSi10Mg parts that mix additive freedom with machined interfaces. Illustrations use an **Example part** only—not a customer flight bracket. Related notes live in [minimum wall CNC vs SLM](https://3dwk.com/resources/minimum-wall-cnc-vs-slm-for-buyers), [SLM support removal and skim notes](https://3dwk.com/resources/slm-support-removal-and-skim-notes), and [powder reuse notes for SLM buyers](https://3dwk.com/resources/powder-reuse-notes-slm-buyers); here we focus on **hybrid strategy labeling** so estimators do not guess.
What hybrid SLM + CNC means for quoting
Typical hybrid flow: SLM near-net → support removal → stress relieve / HIP if required → CNC skim of datums, bores, and seal faces. CNC-first hybrids (machine blanks then add features) are rarer for metal AM buyers. Process pages for aerospace Ti and AlSi10Mg ([SLM Ti-6Al-4V aerospace](https://3dwk.com/en/slm/ti-6al-4v/aerospace.html), [CNC 5-axis Ti-6Al-4V aerospace](https://3dwk.com/en/cnc-5axis/ti-6al-4v/aerospace.html), [CNC 3-axis Ti-6Al-4V aerospace](https://3dwk.com/en/cnc-3axis/ti-6al-4v/aerospace.html)) assume skim and support keep-out notes when lots mix as-built skins and precision interfaces.
Do not bury “machine where needed” inside a notes cloud. Put **SLM + CNC SKIM — faces A/B/C + Ø bore; AS-BUILT elsewhere; SUPPORT KEEP-OUTS named** 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), [what files to send for a CNC quote](https://3dwk.com/resources/what-files-to-send-for-cnc-quote).
Skim stock, supports and interface faces
Leave explicit stock on faces that must meet GD&T after AM distortion. Support keep-outs on sealing or cosmetic skins avoid hand-blend surprises. Soft polymers are out of scope here; Ti and Ni alloys dominate hybrid aerospace asks. Harder alloys (17-4PH ×1.4, IN718/IN625 ×2.5 on the CNC side) amplify skim minutes; aggressive “as-built + ±0.02 all over without stock” frequently auto-route toward **needs_manual** when mid-line bands exceed planning thresholds under **rates.v1.1** / powder estimate packaging.
If HIP, heat treat, or powder pedigree matters, say so beside the hybrid block—see [powder reuse notes for SLM buyers](https://3dwk.com/resources/powder-reuse-notes-slm-buyers). Related wall notes: [minimum wall CNC vs SLM](https://3dwk.com/resources/minimum-wall-cnc-vs-slm-for-buyers).
Bar $/kg and powder planning bands are estimates only (PA66 ~5, 17-4PH ~9, IN718 ~55 on stock side; AM powder is quoted separately). Geometry and skim scope drive the hybrid story more than nominal alloy price.
When hybrid beats CNC-only or SLM-only
Hybrid wins when internals are hard to machine but interfaces need CNC finishes—manifolds, lattice-cored brackets with pad datums, conformal channels with seal flanges. CNC-only wins on simple prismatic envelopes. SLM-only wins when as-built surfaces and looser positional stacks are acceptable. Related process contrast pages: [SLM AlSi10Mg aerospace](https://3dwk.com/en/slm/alsi10mg/aerospace.html) for aluminum AM baselines.
Tolerance and inspection traps
Calling hybrid without a skim map, or demanding full CMM of as-built skins to CNC tolerances, fights automatic bands. Default as-built envelope to looser notes; put functional GD&T only on skimmed datums. Related: [GD&T callouts that raise CNC quote bands](https://3dwk.com/resources/gdandt-callouts-that-raise-cnc-quote-bands), [datum schemes for multi-setup CNC parts](https://3dwk.com/resources/datum-schemes-for-multi-setup-cnc-parts), [CMM sampling plans for CNC lots](https://3dwk.com/resources/cmm-sampling-plans-for-cnc-lots).
Illustration 1 shows an **Example part** hybrid map: SLM body, support keep-outs, and CNC skim pads/bore.
Example part walkthrough
**Example part:** Ti-6Al-4V bracket ~80×60×35 mm, lattice core, two pad datums and one Ø12 bore for a pin—skim those only; skins as-built. With STEP + **HYBRID SLM+CNC; SKIM DATUM PADS + BORE; SUPPORT KEEP-OUT ON SEAL FACE; VIRGIN OR CONTROLLED REUSE PER NOTE**, expect a usable automatic planning band on [quote-new.php](https://3dwk.com/quote-new.php). Same geometry with silent CAD and “print then machine everything” often lands DFM notes or **needs_manual**—without inventing any customer PO.
Illustration 2 contrasts a vague RFQ (“SLM/CNC hybrid”) versus a labeled skim/support pack and the clearer estimate path.
What widens bands fastest
Unlabeled skim scope, support scars on seal faces, powder pedigree silent next to flight-like language, and 100% CMM of as-built lattice. Quantity breaks help unit setup but do not erase hybrid ambiguity—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 **HYBRID SLM+CNC**, name skim faces and support keep-outs, then upload on [quote-new.php](https://3dwk.com/quote-new.php). Service pages: [CNC machining](https://3dwk.com/cnc-machining-service.php), [materials](https://3dwk.com/materials.php). Treat **rates.v1.1** / powder figures as estimates, not invoices. If the UI shows **needs_manual**, answer the hybrid questions rather than forcing a fake firm price.
Common questions
Is hybrid always cheaper than CNC-only?
No. Simple envelopes often stay CNC-only under **rates.v1.1** estimates. Hybrid pays when additive removes ops that CNC cannot reach cheaply.
How much skim stock should I leave?
Enough for distortion plus finish—commonly a named allowance on datum pads and bores. Put the number on the drawing; do not leave “machine to clean.”
Do supports always need CNC cleanup?
Not always. Plan keep-outs on critical skins and accept blend on non-critical zones—see [SLM support removal and skim notes](https://3dwk.com/resources/slm-support-removal-and-skim-notes).
Should powder reuse notes travel with the hybrid pack?
Yes when pedigree matters—see [powder reuse notes for SLM buyers](https://3dwk.com/resources/powder-reuse-notes-slm-buyers)—but skim scope remains the first hybrid label.