PRECISION MILLING FOR PROTOTYPES
From first-concept brackets to pre-production assemblies — Baosheng CNC milling turns your STEP file into a finished part in 1–5 days. 3-axis to full 5-axis simultaneous, aluminum to titanium, 1 piece or 50.
Live capabilities
Tightest tolerance：±0.002mm
Axes available：3 / 4 / 5-axis
Max travel：2,000×1,500mm
Min order：1 piece
Lead time：From 1 day
- 1-piece prototypes welcome
- Free DFM every order
- Quote in 2 hours
- ISO 9001 certified
±0.002mm
Tightest milling tolerance
5-axis
Simultaneous in-house
1day
Fastest prototype lead time
60+
Surface finishes in-house
Certifications
ISO 9001:2015 ISO 13485 Medical IATF 16949 NDA & IP protected Quote in 2 hours 20+ years experience
CNC MILLING VS TURNING VS EDM — WHICH PROCESS FOR YOUR PROTOTYPE?
Milling handles 80% of prototype geometries — but not all. This guide tells you when milling wins, when turning is the better call, and when you need EDM. Getting this right before uploading saves two days.
CNC Milling
3-axis · 4-axis · 5-axis simultaneous
- Flat faces, pockets, slots, counterbores
- Complex 3D sculpted surfaces (5-axis)
- Large prismatic parts (to 2,000mm)
- Multiple features in one setup (5-axis)
- Aluminum, steel, titanium, plastics
- Cylindrical features — possible, not optimal
- Long slender shafts — turning is better
Best for: housing, brackets, enclosures, plates, complex structural parts, all prototypes with non-rotational geometry
CNC Turning
Lathes + live tooling · mill-turn
- Shafts, pins, bushings, connectors
- External/internal threads (ID + OD)
- Concentric bores, excellent roundness
- High L/D ratio parts (long slender)
- Cross-holes, flats — via live tooling
- Non-rotational geometry
- Large flat features, pockets
Best for: rotational prototypes — shafts, connectors, nozzles, valve bodies, fittings
Wire EDM
Wire cutting · sinker EDM
- Hardened tool steel (HRC 60+)
- 2D profile cuts — dies, punches
- Ultra-tight slots — to ±0.002mm
- No heat-affected zone or cutting force
- 3D surface features
- Aluminum, plastics (no EDM)
- Fast turnaround (slow process)
Best for: hardened die inserts, precision slots in hardened steel, 2D profiles requiring no cutting force
Not sure which process? Upload your file — the engineer decides, and explains why in the DFM report.
WHAT CNC MILLING CAN DO FOR PROTOTYPES
Milling’s strength is geometry freedom. Here’s the range — from the simplest bracket to the most complex freeform surface.
3-Axis milling
PRISMATIC PARTS
Flat faces, parallel walls, pockets, slots, counterbores, through-holes, tapped holes. The 3-axis workhorse — fastest, cheapest, most parts fall here. Typical prototype: 1–2 days.
- Fastest
- Lowest cost
- 1-day lead available
3-Axis deep pocket
HOUSINGS & ENCLOSURES
Electronic enclosures, optical housings, manifold bodies. Depth-to-width ratio up to 4:1 with standard tooling — beyond that, extended-reach tools or 5-axis approach paths. Wall thickness minimum 0.8mm recommended.
- Electronics
- Optics
- Pneumatics
5-Axis simultaneous
FREEFORM & SCULPTURED
Impellers, turbine wheels, orthopaedic implants, compound-angle brackets, lens mounts. One setup — tool approaches from any angle. Eliminates repositioning errors that accumulate in multi-setup 3-axis work.
- Aerospace
- Medical
- One setup
Thin-wall challenge
THIN-WALL STRUCTURES
Aluminum frames, drone arms, lightweight brackets. Minimum wall: 0.8mm for 6061 aluminum, 0.5mm achievable with specialized fixturing and reduced feed rates. Walls thinner than 0.8mm are flagged in our free DFM report with suggested alternatives.
- UAV/Drone
- Lightweight structures
- DFM critical
MILLING GEOMETRY LIMITS — QUICK REFERENCE
| Feature / Geometry | 3-Axis milling | 4-Axis milling | 5-Axis milling | Our limit |
|---|---|---|---|---|
| Max part size | 2,000×1,500×800mm | Ø400×600mm | 600×500×400mm | By process |
| Min internal radius | R0.5mm (small end mill) | R0.5mm | R0.3mm | Tool-dependent |
| Max depth-to-width | 4:1 standard · 8:1 special | 4:1 | 6:1 (angled approach) | Varies by material |
| Min wall thickness | 0.8mm Al · 1.0mm SS | 0.8mm | 0.5mm (special fixturing) | DFM review required |
| Surface finish (Ra) | 0.4μm standard · 0.1μm mirror | 0.4μm | 0.2μm on curved surfaces | By material |
| Tightest tolerance | ±0.005mm std · ±0.002mm prec. | ±0.005mm | ±0.002mm (1-setup benefit) | CMM verified |
| Undercut features | Not possible | Limited | Yes — full access | 5-axis recommended |
FROM CAD TO PART — THE REAL TIMELINE
Iteration speed is the whole point of CNC prototyping. Here’s an honest day-by-day breakdown of what happens between your STEP file upload and parts in your hands.
Day 1 — Morning
1.File uploaded · DFM starts immediately
Upload your STEP. Engineer is assigned within 15 minutes. DFM analysis runs for 45–90 minutes depending on complexity. Written report + itemized quote arrive in your inbox by early afternoon.
- Your STEP file uploaded
Day 1 — Afternoon
2.Quote approved · setup begins
You approve the quote. Toolpath programming starts immediately — for simple 3-axis parts this takes 30–60 minutes. Workholding is designed and material pulled from stock. Machines prepped.
- Quote PDF approved
Day 1–2 — Machining
3.Parts running on the machine
Simple prototypes: first chips fly the same afternoon. Complex 5-axis parts: morning of Day 2. Critical dimensions verified with CMM during machining — not just at the end.
Day 2–3 — Finishing
4.Deburring · surface finishing · QC
As-machined: QC and packaging on Day 2. With anodizing: add 2 days. With hard anodizing: add 3–4 days. CMM report issued if ordered. Material certificate attached to every shipment.
Day 3–5 — Delivery
5.DHL/FedEx express dispatch · tracking provided
Export packaging designed to protect precision surfaces. Tracking number in your inbox at dispatch. Typical transit: USA 3–4 days, Europe 3–5 days, next-day within mainland China.
Baosheng — factory-direct milling
Fastest route- Simple Al 6061 prototype：1–2 days
- Medium complexity, 3-axis：2–4 days
- 5-axis complex prototype：3–6 days
- With Type II anodizing：+2 days
- Design change re-quote：Same day, free
- Rush (1-day) available：Yes
Why the difference?
Platform route: your file goes to their system → matching algorithm → 3rd-party shop accepts → they setup → they machine → platform QC → ship.
Baosheng: file arrives → our engineer → our machine → our QC → ship. Two fewer handoffs = two fewer days minimum.
EVERY MILLING PROCESS — IN-HOUSE
Every process runs in our facility. No subcontracting, no handoffs — which means faster lead times and one point of contact when something needs to change.
3-AXIS MILLING
The fastest and most economical route for prismatic aluminum prototype parts. High-speed spindles at 18,000 RPM reduce cycle time and deliver Ra 0.8μm as-machined. Ideal for brackets, plates, enclosures, and fixtures.
- Max travel：2,000×1,500×800mm
- Spindle speed：Up to 18,000 RPM
- Tolerance：±0.005mm std
- Lead time：From 1 day
5-AXIS SIMULTANEOUS
True simultaneous 5-axis for impellers, turbine blades, orthopaedic components, and freeform surfaces. One setup eliminates repositioning error. No multi-setup tolerance stacking. Ideal for your most complex prototype geometry.
- Axes：True 5-axis simultaneous
- Tolerance：±0.002mm achievable
- Undercuts：Full geometry access
- Lead time：3–5 days prototype
4-AXIS INDEXING
Rotary axis adds circumferential features to cylindrical workpieces — radial holes, keyways, gear teeth, and cross-flats — without a separate turning operation. Best for parts that are “mostly cylindrical but with milled features.”
- Rotation：360° indexing
- Max dia.：Ø 300mm
- Feature types：Radial holes, flats, slots
- Lead time：2–4 days
MICRO MILLING
End mills from Ø 0.3mm for fine details — sensor housings, microfluidic channels, connector pins, watch components. Climate-controlled measurement room compensates for thermal drift. Achieves feature widths under 0.5mm.
- Min tool dia.：Ø 0.3mm
- Min feature width：<0.5mm
- Tolerance：±0.003mm
- Applications：Medical · sensors · optics
WHAT DRIVES YOUR PROTOTYPE MILLING COST
Five variables explain 95% of the price. Understanding them before you upload lets you make smarter design decisions.
| Cost driver | Low-cost scenario | High-cost scenario |
|---|---|---|
| Quantity | 50+ pieces — setup amortized | 1 piece — 100% setup in 1 part |
| Axes required | 3-axis, prismatic geometry | 5-axis simultaneous, compound angles |
| Material | Al 6061 — machines in seconds | Titanium — 4× slower cycle time |
| Tolerance | ±0.05mm — standard 3-axis | ±0.002mm — CMM + dedicated setup |
| Surface finish | As-machined Ra 0.8μm — free | Mirror polish Ra 0.1μm — manual labor |
| Feature complexity | Through-holes, flat faces | Deep narrow pockets, thin walls |
DFM TIP — MOST COMMON OVERSPEND
Calling out ±0.002mm everywhere — even on clearance holes and cosmetic pockets — is the single most common unnecessary cost driver on prototype drawings. Each tight-tolerance feature adds CMM verification time. Our free DFM review identifies where it’s actually needed versus where ±0.05mm works fine. Average savings: 20–40% per-part.
Prototype / 1–5 pieces
From $12 / pc
Al 6061 · 3-axis · as-machined · ±0.05mm · 1–3 day lead
Small batch / 10–50 pieces
Save ~40–55% vs 1pc unit cost
Setup amortized · batch scheduling · material savings
Complex 5-axis prototype
From $120 / pc
Al 7075 · 5-axis · ±0.005mm · 3–5 day lead · CMM report
Free DFM review included
Every prototype quote includes a written DFM analysis. The engineer reviews your milling geometry for unnecessary setups, over-toleranced features, thin-wall risks, and finish spec mismatches. Average DFM-driven cost reduction: 20–35%.
Upload STEP · Quote in 2 hours · No obligation
SURFACE FINISHING FOR MILLED PROTOTYPES
The right finish for a prototype is different from production. Here’s what works — and what’s worth spending on at the prototype stage.
Best for prototypes
As-Machined
Ra 0.8–1.6μm · included in base price
- No cost premium — standard output
- Shows toolpath marks clearly — good for fit/function tests
- Fastest lead time — no post-processing
- Dimensional accuracy unaffected
- Specify: “Ra 0.8μm as-machined”
Most popular finish
Type II Anodize
5–25μm · +$3–8/pc · +2 days
- Corrosion protection + color capability
- Black, clear, blue, red, gold — any color
- Grows 2–12μm per side — adjust tight dims
- Works best: 6061, 6063 — avoid 7075, 2024
- Customer-facing prototypes, structural parts
Wear-critical surfaces
Hard Anodize III
25–100μm · +$8–20/pc · +3–4 days
- HV 400–600 — harder than mild steel
- Dark gray/black — no color option
- Critical: +12–50μm per side — compensate dims
- Wear tests, sliding surfaces, aerospace
- Spec: “Type III per MIL-A-8625”
Texture + appearance
Bead Blast
Ra 0.8–3.2μm uniform · +$2–5/pc · +1 day
- Hides toolpath marks uniformly
- Satin-matte “Apple product” finish
- Negligible dimensional change (<0.01mm)
- Usually followed by Type II anodizing
- Best for: consumer product prototypes
Corrosion + solderability
Electroless Nickel
5–75μm uniform · +$8–18/pc · +2–3 days
- Uniform coverage — inside bores too
- HV 500–700 after heat treatment
- Excellent solderability for connectors
- RoHS compliant
- Aerospace, electronics, hydraulics
Optical / precision
Mirror Polish
Ra ≤0.1μm · +$20–60/pc · +2–4 days
- Manual polishing — diamond compound
- Optical reflectors, mould cavities
- Incompatible with anodizing (post-polish)
- Specify: surface and direction of polish
- Only where functionally required
| If your prototype needs to… | Use this finish | Cost add | Lead add |
|---|---|---|---|
| Test fit and function only | As-machined | $0 | +0 days |
| Go in front of customers / investors | Bead blast + Type II anodize | +$5–13/pc | +3 days |
| Prove corrosion resistance | Type II or III anodize | +$3–20/pc | +2–4 days |
| Test wear / sliding behavior | Hard anodize Type III | +$8–20/pc | +3–4 days |
| Solder to or conduct electricity | Electroless nickel or chem-film | +$4–18/pc | +2–3 days |
| Achieve optical clarity or reflectivity | Mirror polish | +$20–60/pc | +2–4 days |
FACTORY FACTS — NO MIDDLEMEN
Platform suppliers broker your order to a third-party shop you’ve never vetted. When the part comes back wrong, there’s a gap in accountability. At Baosheng, the machine that mills your part and the engineer that reviews your DFM are in the same building.
20+
Years of precision milling experience
Aerospace-to-consumer, 3-axis-to-5-axis — our engineers have seen every geometry challenge and solved most of them twice.
50+
CNC milling machines on the floor
3-axis VMCs, 5-axis simultaneous centers, 4-axis rotary tables, high-speed micro milling. No subcontracting — ever.
2HR
Average DFM report + quote turnaround
Not an algorithm. An engineer opens your file, plans the setup, identifies the risks, and prices the job by hand.
98%
On-time delivery rate across all prototype orders
Late? We reship express at our cost, no argument. Tracking from our dock to your door.
CAD FILE GUIDE — WHAT TO SEND WITH YOUR MILLING QUOTE
The file you send determines how fast we can quote and how accurately we can price your prototype milling job. Here’s what works — in order of preference.
STEP
Recommended
ISO 10303 Standard for Exchange of Product Data
Universal, solid geometry, preserves tolerance annotations if added. Fastest to quote — zero conversion, direct to CAM. Works from every major CAD package. Use STEP if you have the option.
- Quote in under 2 hours
IGES
Accepted
Initial Graphics Exchange Specification
Surface model — may require geometry healing before CAM toolpath. Prefer STEP where available. If sending IGES, ensure it’s exported as a solid (not surface-only) from your CAD package.
- May add 30min for healing
.SLDPRT
Accepted
SolidWorks native part file
We open SolidWorks files directly. Retains full feature tree and parametric history — useful for DFM when the engineer needs to check parent-child relationships or design intent. Include version note.
- Best for DFM depth
PDF
No 3D file?
Dimensioned 2D engineering drawing
No 3D CAD model available? Send a fully dimensioned 2D PDF or DWG. We model the geometry from the drawing — free of charge. Include all views, tolerances, thread callouts, and surface finish specifications. Adds 1–2 hours to quote time.
- +1–2hr quote time
What to include alongside your file
Material specification
Grade, temper, and any special cert requirement. e.g. “Al 6061-T6, MIL-DTL-5182”
Required lead time
Tell us your deadline — we’ll quote both standard and rush options.
Surface finish spec
Function-based: “Type II anodize black” or “as-machined, deburr all edges”
Critical dimensions (optional)
Flag the 2–3 features that matter most. Helps the engineer prioritize DFM effort.
READY?
Upload your file now. Engineer response within 2 hours. DFM included. No obligation.
STEP · IGES · SLDPRT · PDF · 2D DWG accepted
CNC MILLING SERVICE FOR PROTOTYPES — QUESTIONS
How is CNC milling different from CNC turning for prototypes?
Milling removes material from a stationary workpiece using a rotating multi-flute cutter — ideal for prismatic, complex 3D, and freeform geometries. Turning rotates the workpiece against a stationary tool — ideal for cylindrical shafts, bores, and threads. Most prototype housings, brackets, and enclosures are milled. Most shafts, connectors, and nozzles are turned. If your part has both, our mill-turn machines handle it in one setup.
What’s the minimum feature size achievable in CNC milling?
With standard tooling: internal radius R0.5mm, slot width 1.0mm. With micro milling tools: internal radius R0.15mm, slot width 0.3mm. These are physical limits set by tool diameter and cutting force deflection — not machine capability. Our DFM review flags any feature that falls below safe limits for your chosen material.
Can I get a 5-axis milling prototype in 1–2 days?
Simple 5-axis geometries: yes, in 2–3 days. Complex simultaneous 5-axis (impellers, freeform surfaces): typically 3–5 days. The constraint is toolpath programming time, not machine speed — a 5-axis impeller toolpath can take 3–4 hours to generate and verify. Rush 5-axis available — discuss your deadline when uploading.
What materials can be CNC milled for prototypes?
We mill aluminum (6061, 7075, 5052, 2024), stainless (304, 316L, 17-4 PH), titanium (Grade 2, Grade 5 Ti-6Al-4V), engineering plastics (PEEK, Delrin, Nylon, Polycarbonate), brass, copper, and exotic alloys (Inconel 718, Hastelloy C-276). All available from 1 prototype piece — no minimum order on any grade.
What files do I need to submit for a prototype milling quote?
STEP files are preferred — upload directly, no conversion needed, fastest quote. We also accept IGES, SolidWorks (SLDPRT), CATIA, Pro-E, SAT, X_T, and 2D PDF/DWG drawings. No 3D file? Send a dimensioned 2D PDF — we model the geometry for free. Include: material spec, surface finish, lead time requirement, and quantity.
Do you offer design changes between prototype revisions?
Yes — and re-quoting is free and same-day. Submit your updated STEP file referencing the previous order. We retain the setup knowledge and toolpath strategy from your last revision — Rev 2 quotes faster and is usually cheaper than Rev 1 because workholding is already solved.
What tolerance can CNC milling hold on a prototype?
±0.05mm general, ±0.01mm standard precision, ±0.002mm on specific features with dedicated setup. Aluminum holds tighter tolerances than steel or titanium due to its lower cutting forces. Don’t specify ±0.002mm everywhere — our DFM review identifies which features actually need it and which can relax without functional impact.
How does your free DFM analysis help with prototype milling?
Our DFM review specifically checks for milling risks: wall thickness below 0.8mm, pocket depth-to-width ratios exceeding 4:1, unreachable internal radii smaller than the smallest available end mill, tolerance callouts on non-critical features, and alloy-finish incompatibilities. Written report with each issue numbered, explained in plain English, and costed. Average cost reduction: 20–35%.
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MILL YOUR PROTOTYPE TODAY.
Upload your STEP file. Free DFM analysis. Itemized quote in 2 hours. Engineer, not algorithm.
✓ Free DFM ✓ No MOQ ✓ Quote in 2h ✓ ISO 9001 ✓ NDA on request ✓ 1-day lead available