Cobalt chrome SLM vs CNC: cost and lead time

The short answer

**Cobalt chrome (CoCr)** parts can be CNC-machined from wrought/bar stock or built by **SLM** then finish-machined on datums. Cost and lead time diverge mainly on geometry, powder versus bar economics, and whether the line stays in automatic **rates.v1.1** bands or flips to **needs_manual**. Put process intent on the RFQ before you compare screenshots.

This guide is for buyers trading SLM vs CNC on CoCr. Illustrations use an **Example part** only. It is distinct from medical-adjacent bracket DFM in [CoCr SLM medical-adjacent brackets](https://3dwk.com/resources/cocr-slm-medical-adjacent-brackets-dfm-quotes).

When CNC CoCr is the default

Prismatic brackets, plates, and features fully reachable with standard cutters usually prefer CNC from bar or plate. You avoid powder parameters, support strategy, and as-built surface stories. **rates.v1.1** planning uses a CNC machine-time coefficient about ×2.2 for CoCr (estimate) and treats hot/CoCr lines above configured USD thresholds as **needs_manual** candidates. Related: [CNC cost drivers](https://3dwk.com/resources/cnc-machining-cost-drivers-buyer-guide), [CNC vs 3D printing](https://3dwk.com/resources/cnc-vs-3d-printing-when-to-choose), [reading a preliminary quote](https://3dwk.com/resources/reading-preliminary-online-quote-min-mid-max).

When SLM CoCr earns the powder

Internal channels, topology-optimized lattices, consolidated assemblies, or shapes that would need many CNC setups are where SLM appears. Plan for machined datums, tapped holes, and sealing faces after build. **rates.v1.1** SLM powder planning band for CoCr is about ~$150/kg (estimate)—not an invoice and not a substitute for quoting the full process chain.

Illustration 1 shows an **Example part** process fork: CNC prismatic lug versus SLM channel body with machined pads.

Cost drivers side by side

**CNC-heavy drivers:** stock form, cutter wear, machine-time ×2.2 planning, fixturing, inspection of hard alloy features.

**SLM-heavy drivers:** powder ~$150/kg planning, build orientation/supports, heat treat / stress relief narratives, HIP if required by your spec, then CNC finish time on datums.

Do not compare a CNC mid for a solid block to an SLM mid for a hollow lattice and call it “the same part.” Parallel RFQs with identical interfaces are the honest method—same pattern as [SLM vs CNC IN718 brackets](https://3dwk.com/resources/slm-vs-cnc-inconel-718-brackets-cost-lead-time) and [IN625 vs IN718 CNC vs SLM](https://3dwk.com/resources/in625-vs-in718-cnc-vs-slm-buyers).

Lead time realities

CNC CoCr prototype lead time is mostly queue + spindle + finish. SLM adds build calendar, cool-down, support removal, and any thermal post-processing before finish machining. Need-by windows must reflect the longer chain when additive is chosen. See [CNC lead time buyer guide](https://3dwk.com/resources/cnc-machining-lead-time-buyer-guide).

DFM notes that change either path

• Call CoCr grade/spec family you actually need; “cobalt chrome” alone is thin
• For CNC: avoid knife walls and EDM-like cavities unless intentional
• For SLM: design support access, minimum walls per process capability, and stock on machined faces
• Threads: often CNC after SLM; say so
• Cosmetic expectations: as-built SLM ≠ milled Ra—see [surface roughness Ra](https://3dwk.com/resources/surface-roughness-ra-for-machined-parts)

Illustration 2 maps RFQ completeness for CoCr CNC vs SLM to automatic band versus **needs_manual**.

rates.v1.1 reminder (estimates only)

Bar planning examples elsewhere on the site (PA66 ~5, 17-4PH ~9, IN718 ~55, IN625 ~60 $/kg) are for those alloys; CoCr CNC is coefficient-driven (×2.2) plus stock reality. SLM powder planning: 17-4PH ~70, IN718 ~120, IN625 ~130, CoCr ~150 $/kg. Line totals above configured thresholds for hot alloys/CoCr auto-route to **needs_manual**. Never treat UI mids as firm invoices.

Packaging the RFQ

• Separate lines or clear notes: CNC path vs SLM+CNC finish path
• Interface dimensions identical if comparing
• Qty, need-by, and whether medical/regulatory paperwork is in or out of scope (do not invent certs)
• Finish and inspection only where functional

Upload on [quote-new.php](https://3dwk.com/quote-new.php). Services: [CNC machining](https://3dwk.com/cnc-machining-service.php), [3D printing](https://3dwk.com/3d-printing-service.php), [materials](https://3dwk.com/materials.php).

Example part walkthrough

**Example part:** CoCr mounting lug, ~60×40×25 mm, two M4, one sealing pad Ra 1.6. CNC prismatic version with complete STEP/PDF should aim for a planning band or explicit manual review under CoCr rules. Lattice-core version with internal channels belongs on an SLM+finish line—not as a sneaky edit to the CNC mid. No customer implant claims, no fake certs.

What to do next

Choose geometry-first: if it mills cleanly, start CNC; if channels dominate, start SLM+datums. Request ranges on [quote-new.php](https://3dwk.com/quote-new.php). If **needs_manual** appears, that is expected on many CoCr lines—answer process notes rather than forcing a gamed automatic price.

Inspection and surface expectations

CNC CoCr can target conventional machined Ra on accessible faces. SLM as-built surfaces need explicit post-process (machine, grind, polish) where function cares. CMM on hard alloys still follows datum quality—poor as-built datums make FAIR painful. See [CMM vs optical](https://3dwk.com/resources/cmm-vs-optical-measurement-machined-parts) and [first article inspection](https://3dwk.com/resources/first-article-inspection-reports).

Quantity effects on CoCr process choice

Qty 1–3 complex lattices often favor SLM+finish despite powder cost. Qty 25 prismatic lugs often favor CNC once fixtures amortize. Put a qty ladder on each process line separately—do not assume one mid scales across processes. Related quantity framing: [CNC vs die casting vs molding by volume](https://3dwk.com/resources/cnc-vs-die-casting-vs-injection-molding-by-volume).

What not to claim on CoCr RFQs

Do not invent implant approvals, patient-matched case studies, or fake ASTM checkbox theater in the upload notes. Keep the RFQ to geometry, material family, process path, qty, and inspection. **Example part** language protects both sides.

Common questions