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CNC Machining: A Complete Guide
This guide provides a systematic overview of CNC machining, detailing its core principles, operational workflows, equipment types, material selections, and industry applications.
Online CNC Machining Service
Partner with Unionfab, a China-based CNC platform integrating in-house manufacturing and vetted supplier networks to get engineer-led DFM, verified quality, repeatable production, and assembly-ready parts.
CNC Milling (3, 4, 5 Axis), CNC Turning, and Mill-Turn Machining
Rapid 1-Day Turnaround with Tolerances Down to ±0.0002"
4 In-House Manufacturing Facilities and 300+ Vetted Suppliers
400+ Advanced CNC Machining Centers (Mazak, DMG MORI, Makino etc.)
ISO 9001, 14001, 13485 & IATF 16949 Certified | NDA Protection
Excellent4.6 out of 5
CNC Instant Quote
Upload Your File, No Login RequiredSTEP | STP | IGS | DWG | DXF | PDF Files and More
*ISO 27001 Certified | Secure File Upload
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.
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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 | - |
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.
CNC Metals
CNC Engineering Plastics
CNC Insulation Material
CNC Rubber
CNC Ceramics
High-performance metallic alloys delivering structural integrity, thermal conductivity, and exceptional mechanical strength for demanding environments.
Superior tensile strengthExcellent thermal & electrical conductivityTight-tolerance machinability
Ideal For: Aerospace components, medical device parts, automotive engine parts, and heavy-duty industrial brackets etc
Materials:
Finishing Options for CNC Machining
A great part deserves a great finish. We offer a diverse selection of surface treatments to enhance the durability, functionality, and look of your CNC machined parts. Browse our capabilities below:
Bead Blasting
Polishing
Anodizing (Type II & III)
Powder Coating
Electroless Nickel Plating
A mechanical surface treatment that bombards the part with fine glass beads at high pressure to remove tool marks and create a uniform, matte texture.
Best For: Achieving a consistent, non-reflective aesthetic finish and hiding minor surface defects on consumer electronics, enclosures, or grip surfaces.
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
We accept both 3D models and 2D drawings. For instant geometry analysis and baseline pricing, please upload your 3D CAD files in STEP, STP, or IGS formats. If your part requires specific tight tolerances, GD&T callouts, or threaded holes, a supplementary 2D drawing in PDF, DWG, or DXF format is required.
We have no strict Minimum Order Quantity (MOQ = 1). Whether you need a single rapid prototype for design validation or a low-volume production run of thousands of parts, our flexible manufacturing network is built to scale with your project efficiently and cost-effectively.
Our standard manufacturing lead time for most CNC projects is 5 business days. For exceptionally simple parts or urgent prototyping needs, we can expedite production and ship in as fast as 1 day. (Please note: Lead times may vary depending on part complexity, total quantity, and any secondary surface finishes required.)
100% Yes. We take intellectual property (IP) protection and data security incredibly seriously. We are proudly ISO 27001 Certified for information security management. Your files are encrypted and shared exclusively with essential engineering staff. We are also fully prepared to sign your Non-Disclosure Agreement (NDA) before you share any CAD files.
Absolutely. By default, every order includes a standard Dimensional Tolerance Report. For production volume orders, we supply comprehensive First Article Inspection (FAI) reports. If your critical components require ultra-precision metrology, full CMM (Coordinate Measuring Machine) inspection is available for an additional fee.
For a deep dive into our quality control processes, please read our guide on Unionfab QC & Inspection Capabilities.
For a deep dive into our quality control processes, please read our guide on Unionfab QC & Inspection Capabilities.
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