Home >Services> CNC Machining
CUSTOM ONLINE CNC MACHINING SERVICE
Industrial CNC Machining.
One Platform.
Production-Ready.
Partner with Unionfab, a China-based CNC machining platform integrating in-house manufacturing and vetted supplier networks, to get engineer-led DFM, verified quality,repeatable production, and assembly-ready parts.
Upload CDA.Get Free DFM Review
STEP, STL, IGES, OBJ and more. We’ll route your part to the right process before production starts.
Instant Pricing • No MOQ • Secure Upload • 10% Off First Order
MACHINING CAPABILITY
3/4/5AXIS
Advanced CNC milling, turning, and mill-turn machining.
SPEED & PRECISION
±0.0002"
1-day turnaround with ultra-tight machining tolerances.
MANUFACTURING SCALE
400+
400+ CNC machines across in-house and partner facilities.
CERTIFIED
ISO
ISO 9001, 14001, 13485 & IATF 16949 certified with NDA-secured manufacturing workflows.
Unionfab — China's CNC Machining Factory and Network
Unionfab combines in-house CNC manufacturing with a vetted supplier network across China to deliver more than just machined parts. With strict quality control throughout the entire production process, we ensure every part meets drawing requirements before shipment and maintains consistent quality across repeat orders.
From machining and finishing to inspection and delivery, our workflow is built to produce assembly-ready parts with reliable tolerances, verified quality, and a wide range of post-processing options. Customers can complete CNC machining, surface finishing, quality inspection, and delivery through one integrated service.
400+
CNC Centers
4
In-House Facilities
300+
Vetted Suppliers
1 Day
Fastest Turnaround
2M+
Parts Made
±0.0002"
Tight Tolerance
3 Axis Machining Factory
4 Axis Machining Factory
5 Axis Machining Factory
CMM Inspection Room
Visit Unionfab CNC Machining Factories Online
3 Axis Machining Factory
4 Axis Machining Factory
5 Axis Machining Factory
CMM Inspection Room
CNC Machining Options
CNC Milling Service
3-, 4-, and 5-axis machining processes for solid plastics and metals. Delivering tight-tolerance prototypes and production parts in just days.
Ideal For: Custom enclosures, mold and die making, precision brackets, and complex planar parts.
CNC Turning Service
Lathes and turning centers for precise cylindrical parts from rod stock. Utilizing live tooling for single-setup, multi-axis machining and rapid production.
Ideal For: Precision shafts, bushings, pins, and tight-tolerance round parts with milled features.
5-Axis CNC Machining Service
Simultaneous 5-axis tool movement for intricate, multi-sided geometries. Achieving aerospace-grade precision and rapid turnarounds through single-setup machining.
Ideal For: Aerospace impellers, medical implants, automotive housings, and engineering-critical applications.
CNC Turn-Mill Machining Service
Integration of lathe turning and multi-axis milling within a single machine center. Machining complex cylindrical features from selected rod stock in one setup for superior concentricity and rapid production.
Ideal For: Complex shafts with flats, cross-drilled components, custom aerospace fasteners, and advanced hydraulic fittings.
EDM Service
Non-contact thermal erosion using electrical sparks. Creating complex, deep cavities in selected ultra-hard alloys with zero mechanical deformation.
Ideal For: Injection mold tooling, sharp internal blind holes, and complex cavities in hardened steels.
Wire EDM Service
Precision cutting via a continuously feeding, electrically charged micro-wire. Delivering micron-level tolerances, sharp corners, and burr-free edges.
Ideal For: Extrusion dies, thick metal plate profiling, delicate thin-walled parts, and intricate undercuts.
CNC Machining Technical Specifications
| Limits for nominal lengths | ISO 2768-m (Default) | ISO 2768-f |
|---|---|---|
| 0.5mm to 3mm | ±0.1mm | ±0.05mm |
| Over 3mm to 6mm | ±0.1mm | ±0.05mm |
| Over 6mm to 30mm | ±0.2mm | ±0.1mm |
| Over 120mm to 400mm | ±0.5mm | ±0.2mm |
| Over 400mm to 1000mm | ±0.8mm | ±0.3mm |
| Over 1000mm to 2000mm | ±1.2mm | ±0.5mm |
| Over 2000mm to 4000mm | ±2.0mm | - |
| Limits for nominal lengths | ISO 2768-m (Default) | ISO 2768-f |
|---|---|---|
| Up to 10mm | ±1° | ±1° |
| Over 10mm to 50mm | ±0°30' | ±0°30' |
| Over 50mm to 120mm | ±0°20' | ±0°20' |
| Over 120mm to 400mm | ±0°10' | ±0°10' |
| Over 400mm | ±0°05' | ±0°05' |
| Limits for nominal lengths | ISO 2768-m (Default) | ISO 2768-f |
|---|---|---|
| Over 3mm to 6mm | ±0.5mm | ±0.5mm |
| Over 6mm | ±1.0mm | ±1.0mm |
| ISO 2768-K (Standard & Default) | ISO 2768-H (Precision) | |
|---|---|---|
| Straightness and Flatness | As tight as 0.05 mm | As tight as 0.02 mm |
| Perpendicularity | As tight as 0.4 mm | As tight as 0.2 mm |
| Symmetry | As tight as 0.6 mm | 0.5 mm |
If your CNC machined parts are part of a larger assembly, we can hold tight tolerances for standard shaft and hole fits based on the ISO 286 system. Please specify the desired fit class on your 2D technical drawing. Common fits we machine include:
Clearance Fits (e.g., H7/g6): For moving parts like sliding bearings and pistons.
Transition Fits (e.g., H7/k6): For accurate location with slight interference, requiring light tapping to assemble.
Interference/Press Fits (e.g., H7/p6): For permanent assemblies requiring pressing or shrink-fitting.
| Finish Tier | Metric (Ra μm) | Imperial (Ra μin) | ISO Grade |
|---|---|---|---|
| Default As-Machined | 3.2 μm | 125 μin | N8 |
| Fine Machined | 1.6 μm | 63 μin | N7 |
| Precision / Smooth | 0.8 μm | 32 μin | N6 |
| High-Precision Grinding | * 0.4 μm | 16 μin | N5 |
| Lapped / Polished | * 0.2 μm | 8 μin | N4 |
| Mirror / Superfinished | * 0.1 μm | 4 μin | N3 |
| CNC Milling | CNC Turning | |
|---|---|---|
| Max Size | 4000 × 1500 × 600 mm (157.4" × 59.0" × 23.6") | Ø 200 × 500 mm (Ø 7.8" × 19.6") Length |
| Min Size | 5 × 5 × 5 mm (0.2" × 0.2" × 0.2") | Ø 2 × 2 mm (Ø 0.08" × 0.08") Length |
While our instant quoting platform uses your 3D CAD files for geometric pricing, any custom dimensions, GD&T callouts, specific fits, or tight surface finishes MUST be explicitly detailed in an accompanying 2D PDF drawing.
CNC Machining Materials
We provide a comprehensive range of CNC machining materials to meet the manufacturing demands of your most rigorous applications.
High-performance metallic alloys delivering structural integrity, thermal conductivity, and exceptional mechanical strength for demanding environments.
Ideal For: Aerospace components, medical device parts, automotive engine parts, and heavy-duty industrial brackets etc
Versatile polymers offering significant weight reduction, chemical resistance, and electrical insulation without compromising dimensional stability.
Ideal For: Semiconductor manufacturing equipment, high-temperature insulators, chemical processing valves, and laser components.
Specialized industrial laminates and composites designed to block electrical currents and withstand thermal shock in sensitive electromechanical systems.
Ideal For: PCB testing fixtures, electrical switchgear components, transformers, and terminal boards.
Flexible, resilient elastomers precision-machined for applications requiring shock absorption, fluid sealing, and vibration dampening.
Ideal For: Custom seals, gaskets, vibration mounts, and shock-absorbing bumpers.
Advanced technical ceramics machined with specialized diamond tooling for environments requiring extreme hardness and thermal endurance.
Ideal For: Semiconductor manufacturing equipment, high-temperature insulators, chemical processing valves, and laser components.
Finishing Options for CNC Machining
An auto-catalytic chemical reaction that deposits a uniform, highly lubricious nickel-phosphorus alloy coating across the entire part, regardless of geometric complexity.
Best For: Intricate internal cavities, blind holes, and tooling components that require superior corrosion and wear resistance with strict, uniform thickness control.
A precise physical or chemical abrasion process that progressively smooths the part’s surface down to an exceptionally clear, mirror-like finish.
Best For: Optical components, light reflectors, and premium decorative hardware requiring maximum visual appeal, cleanability, and minimal friction.
An electrochemical process that converts the metal surface into a highly durable, corrosion-resistant anodic oxide layer that can be permanently dyed in custom colors.
Best For: Aluminum and titanium parts requiring enhanced wear resistance, environmental protection, or strict brand color matching without altering the precise dimensions.
A dry finishing process where free-flowing polymer powder is applied electrostatically and cured under heat to form a tough, continuous protective skin.
Best For: Outdoor industrial equipment, metal frames, and structural components that demand extreme impact resistance, UV protection, and vibrant, long-lasting color coverage.
An auto-catalytic chemical reaction that deposits a uniform, highly lubricious nickel-phosphorus alloy coating across the entire part, regardless of geometric complexity.
Best For: Intricate internal cavities, blind holes, and tooling components that require superior corrosion and wear resistance with strict, uniform thickness control.
Quality Assurance & Inspection
We adhere to a strict multi-stage inspection protocol to ensure every part meets your exact specifications.
Full FAI Documentation: Every order includes a First Article Inspection report (upon request).
Precision Metrology: We utilize state-of-the-art CMM (Coordinate Measuring Machines), profilometers for surface roughness, and calibrated hand tools.
Traceability: All material certifications and heat treatment reports are archived and available for audit.
Standards Compliance: Our quality systems are aligned with international ISO 9001 standards, covering dimensional, geometric (GD&T), and material requirements.
For more details on our quality standards, check out our Inspection Checklist (including both standard and premium options).
FAQs About CNC Machining
What type of CAD files do you accept for CNC quoting?
At Unionfab, we support a wide range of 3D file formats to ensure smooth compatibility with our manufacturing systems. The most commonly recommended formats are STEP (.stp/.step) and STL (.stl). If your design is in another format (such as IGES, OBJ, or others), it can usually be processed as well, but we suggest converting it to STEP or STL for the best results. These formats help preserve critical design details and ensure a more accurate and stable printing outcome.
What is your Minimum Order Quantity (MOQ)?
Typically, many standard 3D printing orders are completed within 1–3 business days. However, the exact lead time depends on the part’s size, complexity, material, and quantity. For a precise timeline, we recommend uploading your design files so our team can provide a detailed estimate based on your specific requirements.
What is the typical lead time for custom CNC machined parts?
The formula below encompasses all cost components involved in an industrial 3D printing quote:
Total Cost = Printing Cost (Material Unit Price × Part Weight) + Complexity Surcharge + Post-Processing + Packaging + Shipping + Customs Duty
For detailed explanation of the cost items above, you can refer to our 3d printing cost guide.
Will my design and 3D models be kept confidential?
At Unionfab, we ensure quality through a strict end-to-end control process. This includes file checks before production, process monitoring, and final inspection to verify part accuracy and consistency. We can also provide inspection reports or additional quality checks upon request, and our facilities follow recognized quality standards to ensure reliable results.
If your project has specific quality requirements, our team will work closely with you to define and meet those standards.
Do you provide material certificates and inspection reports?
Absolutely. We understand the importance of your intellectual property. Unionfab follows strict data security protocols. We are happy to sign a Non-Disclosure Agreement (NDA) before you upload your files. Our internal platform is encrypted, ensuring that your designs are only accessible to the essential technical team involved in your project.
