How To Select The Right Bond Type

Congratulations! If you are on this website, you’ve probably come to the conclusion that a superabrasive grinding wheel will be the best solution to your project’s needs. If you are still considering the pros and cons of the different types of grinding products, check out this article that explains the differences between superabrasive and conventional grinding wheels. 

Once you’ve decided you need a superabrasive solution for your grinding application, what’s the next step? 

SELECTING YOUR BOND TYPE

The bond acts as the glue that keeps the abrasive grains in your grinding wheel connected. The bond's strength, also known as its hardness, determines how well the wheel can handle different materials. 

Harder bonds are typically recommended for softer materials and vice versa. There is also the option to create custom hybrid bonds that are specially formulated to possess unique characteristics that will better support your more specific needs.

A grinding wheel expert can help you narrow down your selection, as there are many different bond types.

Let’s go over the common ones:

  • Resin Bond

  • Metal Bond

  • Vitrified Bond

  • Electroplated Bond

  • Hybrid Bond

RESIN BOND

Resin bonds are the most widely used bond type in superabrasive grinding wheels. Simply put, they are grinding wheels held together with a plastic bond.  They are made from synthetic resins, such as phenolic or epoxy, which is used to hold the abrasive in place. 

Mostly, these types of grinding wheels are formulated and blended as powders which are then cast and hot pressed in steel molds of the desired size and shape of grinding wheel desired.  The specific properties of the bond are determined by the specific resin and additives to get the desired mechanical and grinding properties.

Because of Resin Bond’s resilience and toughness, these grinding wheels tend to be:

  • Easy to use

  • Versatile across a broad range of materials & applications

  • Relatively inexpensive when compared with other superabrasive grinding wheels

METAL BOND

Metal bonds are, as the name suggests, made from metals – such as bronze and iron. Like Resin Bond products, Metal Bond grinding wheels are blended as powders and hot pressed in high temperature alloy or graphite molds as the processing temperature is much higher than resin.

Metal bond is the hardest of the bond types. Because of this, most Metal Bond grinding wheels are made with diamond, the hardest superabrasive, and are used on especially hard materials such as glass, ceramics, and carbides. Between the inherent hardness of the bond and the hardness of the materials being ground, these wheels generate the highest grinding forces and usually require special dressing or conditioning steps during use.  

Benefits of Metal Bond grinding wheels include:

  • Resistance to wear

  • Longest wheel life

VITRIFIED BOND

Vitrified (or more appropriately known as “glass” or “ceramic”) bonds are different from resin and metal bonds in that they have both a mechanical bond like the others, but also a chemical bond between the abrasive (either dIamond or CBN) and the bond itself.  Most commonly, these bonds are engineered with porosity and are “cold pressed” and sintered as opposed to hot pressed.

While the actual glass/ceramic bond is technically harder than metal bonds, the porosity levels make the function better in grinding as the porosity efficiently removes grinding debris (swarf) and brings coolant into the point of grinding. Because of the porosity of these grinding wheels, they are also more readily able to be dressed and formed into specific desired geometries.

Because Vitrified bonded grinding wheels have lower grinding forces and the ability to be readily dressed with rotary dressers, this type of bond is ideal for high volume production grinding applications of hard materials that can most benefit from the:

  • Lower grinding forces

  • Faster grinding cycles 

  • Lower scrap rates

In the case of CDT’s VIPER Vitrified Bond grinding wheels, we have enhanced the bond strength over traditional Vitrified Bonds, coupled with a porous vitrified structure, to more perfectly grind some of industry’s hardest materials like silicon carbide, aluminum oxide, glass, carbide, and others. Our VIPER Bond system provides enhanced dressability, lower grinding forces, and shorter grinding cycles over traditional Vitrified Bond systems.

ELECTROPLATED BOND

An electroplated bond is a metallic bond (typically nickel for superabrasive grinding wheels) in which a single layer of abrasive is adhered or bonded onto a metallic core through a deposition process.  Like all electroplating processes, metallic material is pulled from solution and deposited onto the substrate, encapsulating the abrasive onto the substrate in the same form as the substrate.

Like the other bond types, both diamond and CBN superabrasives are used depending on the application.  Because electroplating is a liquid process, complex shapes and geometries are more readily achieved and generally don’t require dressing when in use.

Another benefit to using electroplated grinding wheels (also referred to as just ‘plated grinding wheels’) is that they are single layer and used wheels are able to “stripped” or reverse plating process and the substrate/core can be reconditioned and used again resulting in potential savings of as much as 40% over new plated products.

To recap, Plated grinding wheels:

  • Generally don’t require dressing

  • Can be designed in complex shapes and geometries

  • Can be reconditioned and used again for cost savings over the life of the wheel

HYBRID BOND

A hybrid bond is a combination of two or more different types of bonds and/or processing methods to create a “Hybrid” that encompasses enhanced properties to achieve better performance in grinding for a specific application.

For example, resin and metal bonds have successfully been combined into a single wheel in our EVO Hybrid Bond grinding wheels designed for the cutting tool industry. In this hybrid resin/metal bond wheel, the hard metal bond is softened to make it more user friendly while maintaining long life.  

New hybrid bonds and technologies continue to be developed to bring enhanced grinding performance to specific production grinding processes.

NEXT STEPS

To dig deeper into why different types of materials require different grinding solutions, check out our previous blog Why Different Materials Need Different Grinding Wheels.

Grinding is a complex process that requires a total “systems” approach. Your grinding solution needs to encompass; the grinder/machine, dressing/truing requirements, material, coolant, and the grinding wheel. 

If you’re ready to move forward with a quote or investigate the advantages of a certain bond type for your specific application, contact us to speak with our team of expert engineers that will help answer your questions and get you started.

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