CNC Grinding Services

Why CNC Grinding Services

Precision CNC grinding removes material through a high-speed abrasive wheel, cutting minute chips from the workpiece surface to achieve surface finish and dimensional accuracy that conventional cutting tools cannot reach. Where milling and turning struggle on hardened material — generating chatter, runout, and tool wear at HRC 60+ — grinding maintains full control, producing Ra 0.2–0.8 μm surface finish and correcting geometric errors in roundness, flatness, and parallelism to tolerances that no prior machining operation can match. For hardened steel components where final dimensions, surface finish, and geometric accuracy all matter simultaneously, grinding is the correct last operation.

Machining Capabilities

Grinding Accuracy

Standard ±0.005 mm | Precision ±0.002 mm on critical features
Surface Roughness

Ra 0.2 – 0.8 μm (standard); Ra 0.1 μm (mirror finish on request)
Max. Surface Grinding Area

Up to 600 × 300 mm
Typical Lead Time

Samples: 3–7 days | Production: 7–20 days

CNC Milling Factory

Established	2000
Number of Machines	70+
Location	Zhongshan

CNC Turning Factory

Established	2000
Number of Machines	30+
Location	Zhongshan

Die Casting Factory

Established	2010
Number of Machines	10+
Location	Zhongshan

Injection Molding Factory

Established	2008
Number of Machines	20+
Location	Zhongshan

Forging Factory

Established	2014
Number of Machines	10+
Location	Zhongshan

Machinable Materials

We support over 52 metals and engineering plastics, offering flexible and reliable material choices for diverse part production. Below is our material information:

Metals & Alloys

Material	Features	Common Grades
Hardened Steel	High hardness and wear resistance, typically requiring grinding for precision finishing after heat treatment.	D2, H13, SKD11, 52100
Stainless Steel	Prone to work hardening and heat buildup, making grinding suitable for achieving high surface quality.	304, 316, 420, 440C
Alloy Steel	High strength and heat-treatable, often ground to achieve final tolerances after hardening.	4140, 4340, 8620
Tool Steel	Extremely hard and wear-resistant, relying on grinding for accurate and fine surface finishes.	P20, M2, H13
Aluminum Alloy	Soft and easy to machine, with grinding used only for high-precision or fine surface requirements.	6061, 7075
Titanium	High strength with poor thermal conductivity, where grinding helps improve surface integrity and accuracy.	Ti-6Al-4V

Types of CNC Grinding Services

Different part geometries and precision requirements call for different grinding methods. Selecting the correct process helps achieve the required dimensions, surface finish and production efficiency.

Surface Grinding

Surface grinding produces flat, smooth and parallel surfaces on plates, blocks, fixtures, mold components and machine parts. It is commonly used as a finishing operation after milling or heat treatment.

Cylindrical Grinding

Cylindrical grinding finishes the external diameter of round components such as shafts, pins, rollers and spindles. It is suitable for parts requiring accurate diameter, roundness, concentricity and surface finish.

Internal Grinding

Internal grinding is used to finish bores, bearing seats and internal cylindrical surfaces. It is often selected for components requiring precise internal diameters, close fits or accurate alignment between internal and external features.

Centerless Grinding

Centerless grinding removes material from cylindrical parts without holding them between centers. It is suitable for producing pins, rods, shafts and other round parts in repeat quantities with consistent diameter and surface quality.

Precision Form Grinding

Form grinding creates specific profiles, contours, grooves or angled surfaces using a shaped grinding wheel. It is commonly applied to tooling, mold inserts, gauges and complex precision components.

When Should You Use Precision CNC Grinding Service?

CNC grinding services are generally selected when conventional milling or turning cannot achieve the required dimensional accuracy, surface finish or geometric control.

Grinding may be suitable when a part requires:

Final machining after heat treatment
Precise bearing or shaft fits
Improved flatness, roundness or parallelism
Fine sealing or contact surfaces
Controlled external or internal diameters
Reduced runout and concentricity error
Smooth surfaces with minimal machining marks
Consistent dimensions across repeat production

Grinding is usually a finishing process rather than a bulk material-removal method. Parts are commonly rough-machined close to their final dimensions before the grinding operation.

CNC Grinding Applications

Precision CNC grinding is widely used for components that require accurate dimensions, smooth surfaces and reliable fit with mating parts.

Automotive Components

Common applications include transmission shafts, valve components, bearing seats, gear components, pins and precision engine parts.

Aerospace Components

Precision CNC grinding can be used for shafts, bushings, hydraulic components, tooling and other parts requiring close dimensional control and consistent surface integrity.

Robotics and Automation

Precision-ground components include guide shafts, locating pins, actuator parts, fixture plates and motion-control components.

Mold and Tooling

Grinding is commonly used to finish mold inserts, core pins, ejector pins, slide rails, punches, dies and precision tooling components.

Industrial Equipment

Typical parts include spindles, rollers, machine shafts, bearing housings, hydraulic components and precision fixtures.

Request Precision CNC Grinding Services

Learn More About Our Material

Typical Part Categories

Precision Shafts & Pins

Motor shafts, drive spindles, gauge pins

Bearing Seats & Bores

Housings with H6 bores ground to accept bearings with guaranteed interference or clearance fit

Mold & Die Components

Cavity inserts, core pins, slide rails

Precision Fixtures & Jig Plates

Flat ground plates with tight parallelism for machining and inspection fixtures

Tolerance & Quality Control

Our quality system is run by an experienced QC team that tracks each job through four checkpoints: incoming material inspection, first-article confirmation (FAI), in-process sampling, and final outgoing inspection (OQC). Nothing ships without passing all four.

On the measurement side, we run CMM coordinate measurement, hardness testing, surface roughness gauging, and optical projection — and keywin issue dimensional reports, CMM reports, and full-inspection records on request.

Tolerances are held to ±0.02–0.5 mm across standard CNC work; tighter specs can be discussed at the quoting stage. We also support customer-defined acceptance criteria and can build a custom inspection plan around your drawings.

How a Grinding Project Works

File Review & Quote

Submit 2D drawings with key dimensions, tolerances, and material/hardness specs. We confirm feasibility and return a quote within 24 hours.

Pre-Grind Machining Check

If the part requires rough machining before grinding, we verify sufficient stock allowance (typically 0.1–0.3 mm per surface) and surface condition.

Wheel & Fixture Setup

Select abrasive type, grit, and bond to match material and finish target. Set up workholding to minimize deflection.

Grinding & In-Process Gauging

Run programmed grinding passes with in-process measurement to confirm dimensions are tracking correctly before final pass.

Surface Verification

Measure Ra with contact profilometer; check flatness, roundness, or cylindricity as required.

Post-Processing & Delivery

Apply specified surface treatment, clean and package, ship with dimensional report.

FAQ

What's the difference between CNC grinding and CNC milling?

Milling uses rotating multi-flute cutters to remove large amounts of material quickly. Grinding uses abrasive wheels to remove very small amounts at high precision — it's used after rough machining to hit tight dimensional tolerances (±0.002–0.005 mm) and achieve fine surface finishes (Ra 0.2–0.8 μm) that milling can't reach. If your part needs bearing-fit tolerances, sealing surfaces, or mirror finishes, grinding is the answer.
What tolerances can CNC grinding hold?

For most jobs: ±0.01 mm on dimensions, Ra 0.4–0.8 μm on surface finish. For precision applications — bearing seats, gauge pins, sealing surfaces — we can hold ±0.005 mm on diameter. Share your drawing and we'll confirm what's achievable before quoting.
How much stock should I leave for grinding?

As a rule of thumb, leave 0.1–0.3 mm of stock per surface for rough-machined parts going to grinding, and 0.05–0.1 mm for semi-finished parts. If you're not sure, share your process drawing and we'll advise. Leaving too little means we can't clean up the surface fully; too much slows the process and may generate heat that affects the material.
Do you grind aluminum and non-ferrous materials?

Yes. We grind aluminum, brass, copper, and titanium. Non-ferrous materials require different wheel types and dressing intervals to avoid loading. We adjust the setup accordingly.
Can grinding be the only operation, or does my part need CNC machining first?

Both are possible. If you're starting from stock bar or plate, the part typically needs rough CNC machining first to remove bulk material, leaving a controlled stock for grinding. If you're supplying a pre-machined part for a final grind, we can work directly from your semi-finished component. We handle both routes.
What is your MOQ for grinding jobs?

No minimum — we take single-piece prototype work. Sample lead time is typically 3–10 working days for standard materials and operations.