The short answer
Leaving faces **as-machined** before Type II anodize is a packaging decision, not a default. Some sealing lands, electrical grounds, and tolerance-critical bores should stay uncoated or receive mask/plug plans. Other cosmetic covers want blast + Type II everywhere. Saying which faces stay as-machined keeps [quote-new.php](https://3dwk.com/quote-new.php) **rates.v1.1** finish estimate bands honest.
This guide is for buyers packaging aluminum RFQs. Illustrations use an **Example part** only—not a customer anodize lot. Related finish reading: [anodizing Type II vs Type III](https://3dwk.com/resources/anodizing-type-ii-vs-type-iii), [chem film vs Type II anodize](https://3dwk.com/resources/chem-film-vs-type-ii-anodize-aluminum), [how anodize choice changes CNC RFQ cost](https://3dwk.com/resources/how-anodize-choice-changes-cnc-rfq-cost).
What “as-machined before Type II” means
As-machined means the CNC surface (and its Ra) is the starting condition for anodize or for a masked keep-out. Type II sulfuric anodize adds thickness and can slightly shrink clearances; it also highlights machining witness. Electronics-thermal and drone aluminum combos ([CNC 3-axis Al 6061 electronics-thermal](https://3dwk.com/en/cnc-3axis/al-6061/electronics-thermal.html), [CNC 3-axis Al 6061 drone](https://3dwk.com/en/cnc-3axis/al-6061/drone.html), [CNC 5-axis Al 6061 electronics-thermal](https://3dwk.com/en/cnc-5axis/al-6061/electronics-thermal.html)) often mix cosmetic shells with uncoated ground pads—label both.
Put a **MASK / AS-MACHINED KEEP-OUT** map on the PDF. Do not write only “Type II black” if three bores must remain conductive. Background: [DFM checklist before an online CNC quote](https://3dwk.com/resources/dfm-checklist-before-online-cnc-quote), [surface roughness Ra for machined parts](https://3dwk.com/resources/surface-roughness-ra-for-machined-parts).
Ra, blast and cosmetic traps
Leaving rough tool marks under clear or black Type II makes machining lines permanent. If cosmetics matter, call bead blast or another prep **before** anodize—and say which faces. If a sealing land must stay sharp, forbid blast there. Selective blast + selective mask is normal; silence creates either over-blasted seals or under-prepped cosmetics. See also [bead blast vs tumble finish on CNC RFQs](https://3dwk.com/resources/bead-blast-vs-tumble-finish-cnc-rfq).
Soft materials differ: PA66 is not Type II anodized—do not copy aluminum finish notes onto plastics. For metals, **rates.v1.1** machine-time coeffs still matter on the CNC step (PA66 ×0.8, 17-4PH ×1.4, IN718/IN625 ×2.5, CoCr ×2.2) even when the finish story is aluminum-only.
Threads, inserts and electrical grounds
Tapped holes may need plug/mask plans so threads stay gaugeable. Wire inserts often install after anodize—name the sequence ([Helicoil vs tapped holes for CNC aluminum](https://3dwk.com/resources/helicoil-vs-tapped-holes-cnc-aluminum)). Ground pads and EMI lands that must stay as-machined (or chem-film only) need explicit keep-outs. Bar $/kg planning bands (estimates only): PA66 ~5, 17-4PH ~9, IN718 ~55, IN625 ~60—useful when mixed-metal assemblies share an RFQ, even if Type II applies only to the aluminum piece.
When full Type II is fine
Non-sealing covers, brackets, and housings without electrical keep-outs can often take full Type II after a uniform prep. Still state color, sealed vs unsealed if you care, and whether dye is required. If line mids climb on complex mask maps—especially when CNC + finish packaging exceeds ~$2000 planning bands on hot-alloy siblings in the same PO—expect **needs_manual** clarification rather than a fake firm finish price.
Illustration 1 shows an **Example part** with cosmetic Type II faces versus as-machined ground and seal keep-outs.
Thickness, fit and dye notes
Type II build-up is small but real on close fits. If a bore must stay H7-class after dye, say whether you will size for coating, mask the bore, or machine after anodize. Dye color callouts without keep-outs still leave grounds and threads ambiguous. Sealed vs unsealed Type II changes corrosion packaging—state preference when the enclosure sees moisture. Related: [chem film vs Type II anodize](https://3dwk.com/resources/chem-film-vs-type-ii-anodize-aluminum) when you need conductivity instead of dye cosmetics.
Default non-critical exterior faces to a single prep + Type II recipe. Put special keep-outs only where function demands them so estimators do not invent a full selective-rack fantasy.
Example part walkthrough
**Example part:** 6061-T6 electronics cover ~120×80×10 mm, exterior Type II black after light bead blast, interior pocket as-machined Ra 1.6 max, three M3 bosses masked for post-anodize insert install, two ground pads AS-MACHINED KEEP-OUT. With STEP + mask map, expect a clearer finish-inclusive planning band on [quote-new.php](https://3dwk.com/quote-new.php). Same CAD with only “anodize black” often triggers DFM questions or **needs_manual**—without inventing any customer dye lot.
Illustration 2 contrasts a vague anodize note versus a keep-out map RFQ block and the clearer estimate path. Semiconductor-adjacent envelopes: [CNC 3-axis Al 6061 semiconductor](https://3dwk.com/en/cnc-3axis/al-6061/semiconductor.html).
What widens bands fastest
No mask map, blast-everywhere on sealing lands, unspecified dye, and mixing Type III wear notes with Type II cosmetics. Quantity breaks help unit CNC cost but do not erase racking/mask labor—see [how quantity breaks change CNC unit cost](https://3dwk.com/resources/how-quantity-breaks-change-cnc-unit-cost), [what needs_manual means](https://3dwk.com/resources/what-needs-manual-means-preliminary-quote).
What to do next
Draw keep-outs, name prep + Type II, state thread/insert sequence, 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** min/mid/max as estimates, not invoices.
Common questions
Should every face stay as-machined before Type II?
No. Cosmetics usually want controlled prep. Reserve as-machined keep-outs for seals, grounds, and tight fits you intentionally leave uncoated or differently finished.
Does Type II hide poor machining?
Usually the opposite—it can highlight tool marks. Spec Ra and prep where appearance matters.
Can I anodize first and machine critical bores after?
Sometimes (machine-after-anodize). Say so explicitly; it is a different process path than mask-before-anodize.
How do hot alloys relate if the part is aluminum?
They matter when the same RFQ mixes aluminum Type II parts with IN718/IN625/CoCr siblings whose **rates.v1.1** coeffs widen the PO mid into manual review.