The short answer
On an SLM RFQ, **support removal** and **skim stock** are not the same quote package as “print the STL.” Supports that touch mating faces, internal channels, or thin lattices change powder minutes, post-processing labor, and machining follow-up. Silence on support keep-outs and skim allowances is what widens many [quote-new.php](https://3dwk.com/quote-new.php) **rates.v1.1** / powder estimate bands—not the bounding box alone.
This guide is for buyers packaging Ti-6Al-4V SLM RFQs. Illustrations use an **Example part** only—not a customer flight fitting. Related orientation notes live in [SLM build orientation notes for buyers](https://3dwk.com/resources/slm-build-orientation-notes-for-buyers), [minimum wall CNC vs SLM for buyers](https://3dwk.com/resources/minimum-wall-cnc-vs-slm-for-buyers), and [Ti-6Al-4V CNC vs SLM cost and lead time](https://3dwk.com/resources/ti6al4v-cnc-vs-slm-cost-lead-time); here we focus on **how to label support removal and skim** so estimators do not guess.
What support removal and skim mean for quoting
Support removal is the post-build work to cut, grind, or machine away sacrificial structures. Skim (or “machine stock”) is intentional extra material on faces that will be CNC-finished to datum or seal quality. For quoting, also say which faces may keep support witness marks and which must be support-free. Process pages for titanium aerospace and medical-adjacent SLM ([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 clear support/skim notes when lots mix as-built and machined interfaces.
Do not bury “remove supports somehow” inside a general AM note. Put **SUPPORT KEEP-OUT** and **+SKIM … mm** on critical faces in the PDF and 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).
Orientation, supports and powder path
Build Z choice drives where supports land. Down-facing skins and overhangs need supports that later become labor. Soft polymer analogs (PA66 time coeff ×0.8 under **rates.v1.1** estimates) are not Ti SLM substitutes—titanium powder and HIP / heat-treat routes dominate planning. Hot alloys (IN718/IN625 ×2.5, CoCr ×2.2) share the “aggressive post-process” pattern: dense internal supports and blind channels frequently auto-route toward **needs_manual**, especially when the line mid exceeds configured planning bands (e.g. above ~$2000 for hot alloys/CoCr).
If channels must stay support-free, redesign for self-supporting angles or open access for removal tools.
Powder $/kg planning bands are estimates only (Ti and Ni alloys sit far above commodity aluminum). Treat them as planning inputs, not invoices—see [reading preliminary online quote min/mid/max](https://3dwk.com/resources/reading-preliminary-online-quote-min-mid-max).
Skim stock and hybrid CNC
Mating pads, seal lands, and datum faces often need +0.5…+1.0 mm skim (typical order-of-magnitude, not a guarantee) before CNC. Say which faces get skim and which stay as-built. Hybrid plans that combine SLM near-net with CNC finishing should list both processes explicitly. Related: [surface roughness Ra for machined parts](https://3dwk.com/resources/surface-roughness-ra-for-machined-parts), [datum schemes for multi-setup CNC parts](https://3dwk.com/resources/datum-schemes-for-multi-setup-cnc-parts).
Tolerance and inspection traps
Tight true position on as-built lattices without skim stock fights process capability. Default non-critical skins to generous as-built bands and put functional tolerances only on machined interfaces. Related: [CMM sampling plans for CNC lots](https://3dwk.com/resources/cmm-sampling-plans-for-cnc-lots), [GD&T callouts that raise CNC quote bands](https://3dwk.com/resources/gdandt-callouts-that-raise-cnc-quote-bands), [what needs_manual means](https://3dwk.com/resources/what-needs-manual-means-preliminary-quote).
Illustration 1 shows an **Example part** with support keep-outs on mating pads and skim stock callouts on Datum A.
Example part walkthrough
**Example part:** Ti-6Al-4V SLM bracket ~90×60×40 mm, BUILD Z named, SUPPORT KEEP-OUT on three mating pads, +0.8 mm skim on Datum A face before CNC, internal channel must be support-accessible or redesigned, as-built Ra acceptable elsewhere. With STEP + clear support/skim labels, expect a usable automatic planning band on [quote-new.php](https://3dwk.com/quote-new.php). Same geometry with “print and clean somehow” often lands DFM notes or **needs_manual**—without inventing any customer PO.
Illustration 2 contrasts a vague RFQ (“SLM Ti somehow”) versus a labeled support/skim block and the clearer estimate path.
What widens bands fastest
Unlabeled supports on mating faces, “no marks anywhere” without redesign, missing skim on datums, and 100% CT of every lattice strut with no sampling plan. Quantity breaks help unit cost but do not erase support-labor risk—see [how quantity breaks change CNC unit cost](https://3dwk.com/resources/how-quantity-breaks-change-cnc-unit-cost).
What to do next
Mark **SUPPORT KEEP-OUT** faces, state **+SKIM** on datums, name BUILD Z preference, 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 min/mid/max as estimates, not invoices. If the UI shows **needs_manual**, answer the support questions rather than forcing a fake firm price.
Common questions
Can supports always be chemically removed without notes?
Not reliably on Ti mating faces. Mechanical removal and skim CNC are common—label keep-outs instead of assuming chemistry alone.
Does more skim always help quotes?
Skim helps datum finishes but adds powder and CNC minutes. Over-skimming every face widens the **rates.v1.1** band; skim only interfaces that need it.
How do hot alloys change support quotes?
Dense supports in IN718/IN625/CoCr raise post-process labor under higher time coeffs (×2.5 / ×2.2 estimates). Expect wider bands or manual review when channels trap supports.
Should orientation notes come first?
Yes—pair this guide with [SLM build orientation notes for buyers](https://3dwk.com/resources/slm-build-orientation-notes-for-buyers). Orientation decides where supports land; removal notes decide how you clean them.