CNC Grinding

What is CNC grinding?

CNC grinding is a machining process that uses a rotating abrasive wheel to remove material from a workpiece at high speed.

The CNC part of the process refers to the use of computer numerical control (CNC) to precisely control the movements of the grinding wheel. This allows for high accuracy and repeatability.

Up until the early 1980s, CNC grinding was reserved for the finishing stages of production and was utilised to ensure smooth surfaces and a good finish to a workpiece. Advancements in technology, however, have made CNC grinding machines far more powerful and versatile across all stages of production.

Today, the CNC grinding process is typically divided into two stages: roughing and finishing. Roughing is the initial stage of the process, where the grinding wheel removes a large amount of material from the workpiece. Finishing is the final stage of the process, where the grinding wheel removes a small amount of material to achieve the desired surface finish. Both stages utilise different grinding wheel structures to achieve their desired outcome.

What is a CNC grinding machine?

CNC grinding machines use a rotating, abrasive wheel to grind away material from a workpiece.

At a basic level, machines will feature a bed to hold the workpiece and a high-speed wheel; some machines will move the head of the grinder across the workpiece, or the workpiece will move around a stationary head. 3 to 5-axis are common for positioning the wheel head and workpiece.

A grinding machine is a force multiplier in any production facility. It can produce a wide range of components in all manner of materials and in an array of hardened/coated conditions.

Nothing compares to the precision of a CNC-ground surface.

This precision is achievable thanks to decades of innovation and development.

The CNC grinders of today are extremely capable production centres that can manufacture accurate parts at a blistering rate, so choosing the right grinding machine can make all the difference for manufacturers.

What is a grinding machine used for?

CNC grinding machines gradually shape a workpiece to remove surface roughness and achieve fine tolerances; most machine shops will use these machines to produce a high-quality surface finish on a component.

Where complex coating or hardening processes have been applied to a component, conventional milling or turning consumables become too costly for metal removal; here, grinding provides a cost-effective solution.

For many engineers, grinding is viewed as a finishing process undertaken towards the final stages of manufacture, when the added value of a component is extremely high. With the advancements in grinding wheel technology, grinding machines are now considered for use earlier in the manufacturing process to remove larger amounts of metal.

Applications of CNC grinding

There are a huge number of grinding processes and machines, including surface, centreless, cylindrical, internal, jig, continuous dress, creep feed, multi-axis and special grinding.

With such a large variety of processes available to engineers, grinding finds use in many applications. It is a good option for any industry that needs to quickly remove large quantities of material from a workpiece or achieve good surface finishes across components.


What industries use CNC grinding?

Aerospace and Defence

The state-of-the-art components produced by the aerospace and defence industries, such as landing gear and jet engine components, are made from challenging materials with low machinability ratings and require absolute precision. CNC grinding machines are used to achieve good material removal rates and surface finishes from superalloys.

What industries use CNC grinding?


Automotive manufacturing requires both speed and precision. CNC grinders are used to maximise metal removal rates when producing engine components, like fuel injection systems, cam and crankshafts and turbochargers.

What industries use CNC grinding?

Machinery & tooling

CNC grinding machines can produce components to tight tolerances quickly, making them useful for those producing parts for machinery, like spindles and pumps. They’re also used to create precision machine tools, like HSS or carbide inserts or rotary tools, skiving tools, as well as punches, dies and precision gauging.

What industries use CNC grinding?

Medical devices

The medical industry uses grinding machines in their post-processing stages to meet regulatory requirements. Surgical tools, dental equipment and prostheses are common applications.

What industries use CNC grinding?


Parts in the energy sector are often large, heavy and complex. Grinding machines are used to help machine parts for wind turbines, motors and compressors.

How does a grinding machine operate?

With a focus on process efficiency, the latest machines offer economy and versatility in the production of a wide variety of workpieces and parts.

These include indexable inserts, rotary and profile tools, gear-cutting and cold-forming tools, medical instruments and implants and turbine components for aero and power-generation engines.

Cost-effective mass production is ensured by the consideration of every process parameter, and providing customisation to the required grinding task through the supply of appropriate individual elements: from the programming of grinding and simulation software, to fully automated loading and unloading robots. Input of data can be via the machine interface, a macro-based programming module or via CAD/CAM toolpath information.

Common types of grinding

1. Surface grinding
Surface grinding is traditionally horizontal, with either a square or circular table, alongside a straight-type wheel or cup-type wheel.
  • Workpieces and components are mounted on a rotary or reciprocating table.
  • This is brought towards the grinding wheel.
  • The grinding wheel is mounted on a spindle.
  • Dressing of the wheel will utilise a single-point diamond.
2. Centreless grinding
Centreless grinding, as the name suggests, removes the need for centre holes (used by the workholding device).
  • Workpieces rest on a work-rest blade.
  • A second regulating wheel backs up the first.
  • The grinding wheel’s rotation ensures the workpiece rests firmly against the regulating wheel and work-rest blade.
  • The regulating wheel works in the same direction as the grinding wheel, controlling feed.
3. Cylindrical grinding
Resembling lathe-turning processes, cylindrical grinding grinds a cylinder's surface. Because they offer greater accuracy and surface finishes than lathes, they can be considered an alternative when adopting a peel grind process for higher removal rates.
  • A grinding wheel makes contact with a rotating workpiece.
  • The grinding wheel rotates at a calculated rate to ensure the metal-cutting action is optimised.
  • The table is able to reciprocate as the component rotates.
  • A cylindrical surface could be tapered, contoured or straight.
4. Internal grinding
Used to finish bores with high accuracy, internal grinding typically uses a collet or chuck to hold a component. Bores may be formed, threaded, tapered or straight.
  • Workpieces are rotated with a motorised headstock.
  • Grinding wheels rotate at far higher speeds than external cylindrical processes.
  • Consideration for cooling the component and removal of debris is needed to ensure a robust, repeatable process is achieved.
5. Special grinding
Special grinding covers highly-specific grinding scenarios or grinders produced for special purposes.
  • Tool grinders manufacture and resharpen rotary tools like milling cutters.
  • Thread grinding machines help create threaded components and gauging.
  • Jig grinders drive tapered and straight holes into a part.
  • Continuous dress is typically used for larger, alloy-based components where large volumes of material must be removed. The diamond dressing roll (reverse plated or infiltrated) will drive into the wheel as it cuts the component. This refreshes the sharpness of the grain and reduces heat build-up as the grinding wheel remains free-cutting.
  • Creep feed grinding utilises higher table feeds for each series of cuts before requiring a conditioning cycle to refresh the grinding wheel.
  • Multi-axis grinding can be utilised for part manipulation, allowing for multiple features to be machined in one cycle, or to generate complex 3D geometries and utilise all axes in a synchronised motion, the same as a conventional CNC machining centre.

6 Benefits of CNC grinding

Accuracy and repeatability

Grinding can produce parts with very tight tolerances, which is essential for a huge number of applications and industries, like aerospace and medical. Waste is also reduced through grinding.

Complex shapes

Grinding can be used to produce complex shapes or strong surface finishes that would be difficult or impossible to produce with other machining methods.

Range of materials

Grinding can be used to machine a wide range of materials, including hardened steel, nickel alloy, samarium cobalt, aluminium, brass, and ceramics. Coated materials, where milling or turning consumables would rapidly fail, can also be machined via grinding.


Grinding is a relatively fast process. High-end modern CNC grinders can quickly remove huge quantities of material quickly, which can save time and money.

Low consumable costs

When reviewed as cost per part, the life of a grinding wheel offers economical value as it contains thousands of cutting faces. Replating certain wheel types reduces the cost per part even further.

Range of options

There are a huge number of grinding machines available on the market to suit different needs and production settings.

Tips for effective grinding

- Choose the right grinding tool
The type of grinding wheel you use will depend on the material you are grinding, your desired surface finish and required metal removal rates. Many different types of grinding wheels are available, each with its own properties. To ensure success, it is important to choose the right grinding wheel for the job. Grain type and size, hardness of bond, porosity, and firing process are some of the factors that can be adjusted to suit individual needs. For more advice, read our blog on how to choose the right grinding machine.
- Find the correct grinding parameters
CNC Grinding parameters include the feed rate, wheel speed, wheel conditioning and depth of cut. These parameters will need to be adjusted depending on the material you are grinding and your desired material removal rate and surface finish results.
- Use coolant
A good quality coolant system is essential for CNC grinding. A coolant will help to cool the grinding wheel and the workpiece, which can generate intense heat. It will also help flush away the chips created during the grinding process and clear debris from the wheel itself to prevent accidents, variation in your grinding process and damage to the components. Coolant extends the life of the grinding wheel and the workpiece, and improves the quality of the finished surface.
- Wheel conditioning
A grinding wheel can be dressable or non-dressable in design. Where dressable wheels are used, re-sharpening of the wheel grain (microfracturing) or removal of dull grain and replenishment of the desired form can be controlled to microns via a dressing method. Single-point diamonds, dressing disks or pre-shaped diamond rolls can be utilised within your process. Each has their benefits and provides the ability to adjust how the grinding wheel reacts when cutting and the surface finish produced.
- Maintenance
Typically working to micron level tolerances, how you prepare your grinding machine is key to continued successful outcomes. Workholding, such as collets and live centres, are active within the grinding environment. Cleanliness of contact parts and moving components will maintain the alignment and repeatability required. Your grinding machine will also need to be serviced regularly by a professional.

How much does a CNC grinding machine cost?

Grinding machines are often purchased for a process or a product, rather than being a stand-alone machine with a standard layout. As such,
the price is inclusive of an end-to-end, turnkey package.

Machine capacity (component size)

Estimated price when new

3-axis, up to 1/2m £200,000 – £600,000
3-axis, up to 3m+ £600,000 – £1,500,000
5-axis, up to 1/2m £300,000 – £900,000
5-axis, up to 3m+ £800,000 – £2,000,000

Grinding FAQs

Why should I choose a CNC grinding machine?

CNC grinding machines are great for industries or applications where speed, surface finish, repeatability, and accuracy are priorities.

It is also a choice when consumable costs of milling or turning are high.

What are the disadvantages of CNC grinding?

  • Machines and tools can be expensive due to the accuracy required.
  • They require attentiveness to cleanliness.
  • Certain machines are sensitive to their environment.

Why is coolant so important for CNC grinding machines?

Grinding processes can produce a lot of heat and may alter the surface structure of a component. Coolants are essential to stop the workpiece from overheating; they also support tool life and machine condition.

Dependant on material, an oil or water-based coolant should be used. Dry grinding of different steels is possible, but is time-consuming.

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If you have any questions about our machines, or interest in setting up a new machining process. Our expert team are more than happy to help.

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