CBN and Diamond Tooling
applications require different levels of precision and control when it comes to cutting, grinding, and polishing materials. One of the key factors in achieving these desired outcomes is the type of tooling used. Diamond and CBN (cubic boron nitride) tooling have become increasingly popular in the industrial cutting and grinding market due to their exceptional hardness and durability. Kemet, a leading manufacturer of precision surface finishing and polishing equipment, offers a comprehensive range of diamond and CBN wheels. These wheels range from standardised to customised options, with diameters ranging from 3mm up to 750mm based on FEPA (Federation of European Producers of Abrasives) standard shape and/or custom design.
One of the most critical aspects of diamond and CBN tooling is the bonding material used. The bonding material's primary purpose is to hold the abrasive grain particles together, allowing them to perform their cutting or grinding functions effectively. Kemet offers four types of bonding materials that are tailored to specific materials and applications.
Vitrified Bonds: Vitrified wheels have a glass bond composition, making them highly effective for precision grinding in the tool and die market. These wheels hold their form exceptionally well, resulting in a high ratio of stock removal to wheel use.
Electro Plated: Electro plated grinding wheels have a single layer of abrasive material that's exposed to the surface. This method of bonding is excellent for achieving a high level of precision and control in cutting or grinding applications.
Resin Bonds: Resin bonding materials typically contain phenolic resins, filler materials such as copper, and an abrasive material like diamond or CBN. The mixture is then compressed into the desired shape and cured. Resin bond is widely used in the cutting tools industry and offers excellent performance in terms of cutting speed and tool life.
Metal Bonds: Metal bonding materials are typically made by sintering powdered metals and filler materials along with an abrasive like CBN or diamond. These bonds are incredibly strong and provide a grinding wheel that holds its shape well. Metal bonds provide high durability to grinding wheels, reducing the frequency of required dressing.
Besides bonding material, the grit size and type of diamond or CBN significantly influence the cutting or grinding outcomes. Choosing a coarse grit size is ideal for high removal rates, rough surfaces, and better tool life. On the other hand, a fine grit size is suitable for lower removal rates, fine roughness on the workpiece, and shorter tool life.
At Kemet, we manufacture all of our products on a made-to-order basis, which includes both new tools and reworking existing ones. However, please note that only electroplated and vitrified bond wheels are eligible for reworking. Our standard precision for all Kemet wheels is ±20 μ for dimension, a maximum of 5 μ for runout, and an H7 tolerance for bore diameter, unless otherwise specified by the customer. We take great care to meticulously inspect and verify the quality of all of our products to ensure their excellence.
New and Re-bonding Services for Used Wheels - How it Works
If you have used Diamond or CBN wheels that need a new lease of life, Kemet can help. Simply contact our team and we will guide you through the process of returning the used wheels for rebonding. Rest assured that the rebonding process will not compromise the quality of the wheels. For more information, please feel free to contact us.
Core Material Selection
When it comes to selecting the core material for Diamond and CBN wheels, carbon fibre has emerged as a preferred option due to its mechanical strength and ability to dampen vibrations. This material can reduce the weight of the wheels by up to 70%, making it especially beneficial for larger wheels where excessive weight can strain the motor shaft and bearings. It is crucial to ensure that heat generated during the grinding process is adequately dissipated to prevent the wheels from overheating. Using carbon fibre and/or aluminium can help with heat distribution. Additionally, we highly recommend grinding with coolant as it can not only prevent overheating but also help maintain the surface quality of the workpiece.
| CORE MATERIAL | VIBRATION DAMPENING | HEAT DISSIPATION | MECHANICAL STRENGTH |
|---|---|---|---|
| ALUMINUM | Poor | Very Good | Very Good |
| STEEL | Poor | Good | Very Good |
| CARBON FIRBE | Good | Poor | Very Good |
Industries Served
- Aerospace
- Automotive Industry
- Bearing
- Compressor/Valves
- Manufacturing industry
- Oil & Gas
- Precision Engineering
- Pumps
Diamond and CBN Wheel Applications: Choosing the Right Wheel for the Job
Diamond and CBN wheels have a range of applications, but it is crucial to select the right type of wheel for the specific material being worked on. CBN wheels are designed for grinding all types of steel materials, as long as the material has a minimum hardness of 52HRC. Diamond wheels, on the other hand, are best suited for materials that are hard and brittle. Choosing the wrong grain size or type of wheel can lead to poor results on the workpiece and/or a shortened lifespan for the wheels, which could ultimately result in grinding process failure. Diamond and CBN wheels can be used for various applications, some of which include:
- Brake Industries
- Engine Valve Grinding
- Ferrite material
- Piston Ring
- Optical Lens, Glass & Polycarbonate
- Resharpening Cutting Tool
- Fibre Cement Cutting & Profiling
- Rubber Belt Grinding & Profiling
It is important to select the appropriate wheel for each application to achieve optimal results and avoid unnecessary expenses due to damaged wheels or poor workpiece quality.
Camshaft Grinding
Paper Roll Grinding
PCD Tool Grinding
Peripheral speed
The peripheral speed of a grinding wheel has a significant impact on the quality of the grinding process. When the peripheral speed is increased, the grinding forces are reduced, leading to less deviation of the workpiece from its desired form. This decrease in grinding forces results in less load on the individual grits, allowing them to be retained in the bond for a longer period. Consequently, the wheel's lifespan is increased. Another benefit of increasing the peripheral speed of the wheel is the decrease in chip thickness, leading to improved grit coverage by the bond. This, in turn, reduces surface roughness, resulting in a smoother surface finish.
However, it's important to note that thermal effects can cause wear on diamond and CBN grit, which can reduce the bond's ability to retain the abrasive grits. Therefore, it's recommended to use cutting fluid during the grinding process to achieve a high material removal rate while minimising wheel wear. For optimal performance of Diamond and CBN wheels, it's essential to use recommended peripheral speeds. The recommended wheel peripheral speed varies depending on the wheel size, bond type, and material being ground. Customers can contact Kemet's team for guidance on selecting the appropriate wheel and the recommended peripheral speed for their specific application.
Recommended wheel peripheral speed for Diamond and CBN wheel
| Wheel type | Wet grinding cup wheels | Wet grinding peripheral wheel | Dry grinding cup and peripheral wheels |
|---|---|---|---|
| Cerabon | 35...70 m/s | 35...90 m/s | Not recommended |
| Electroplated | 15...25 m/s (D) | 15...25 m/s (D) | 10...20 m/s (D) |
| 30...100 m/s (B) | 30...100 m/s (B) | 15...20 m/s (B) |
Electroplated Diamond and CBN Tools: Tips for Selection and Usage
The use of electroplated Diamond and CBN tools requires not only the proper selection of Diamond or CBN, but also the appropriate spindle rpm and coolant application. It's essential to choose the correct wheel for the material being ground to avoid poor results or a short life span of the tool. CBN wheels are ideal for grinding steel materials with a hardness of at least 52 HRC, while diamond wheels should be used for hard and brittle materials. Incorrect selection of grain size can lead to failure of the grinding process.
