Conventional Abrasives vs. Superabrasives
In Episode 4 of The Grinding Chronicles, Continental Diamond Tool Engineering Consultant Jon VanSant investigates the history of common abrasive materials and their key differentiating characteristics that impact wheel life, cutting performance, and efficiency. Using the wrong abrasive for your application can significantly increase your cost per part. Watch Jon’s video or read the article below to learn the differences between conventional abrasives and superabrasives.
The Grinding Chronicles - Episode 4
Understanding Abrasive Evolution
In the early 1800s, precision grinding relied on naturally occurring abrasives like emery. Fast forward to the late 19th century, and we witnessed pivotal developments with the advent of "Carborundum" or silicon-carbide by Dr. Edward Acheson in 1891, followed by the patenting of 'Alundum' or aluminum oxide by Aldus Higgins in 1904. The landscape changed once again with the introduction of synthetic diamond in 1954 and cubic boron nitride (cBN) in 1957, marking the emergence of superabrasives. Although superabrasives were first synthesized in the 1950’s, it took two decades before commercial products became available.
Distinguishing Characteristics
To understand the difference between conventional abrasives and superabrasives, let’s examine three key characteristics: hardness, thermal conductivity, and friability.
Hardness: An important consideration in abrasive selection, superabrasives like cBN and Diamond demonstrate superior hardness compared to Aluminum Oxide and Silicon Carbide. This is part of what makes superabrasives super, and makes them particularly efficient when grinding extremely hard materials.
Thermal Conductivity: Enhanced thermal conductivity facilitates efficient heat transfer during grinding operations, ensuring minimal damage to the workpiece. This is critical where surface finish is concerned.
Friability: Friability reflects the fracture or impact toughness of an abrasive and underscores another crucial aspect. Analysis reveal a substantial disparity between conventional and superabrasives, with the latter exhibiting remarkable compression fracture strength. When comparing the compression fracture strength of diamond and aluminum oxide at a particle size of 400 microns, there is a 10:1 difference between the conventional abrasive and the superabrasive.
Performance Metrics
Moving beyond physical attributes, an examination of performance metrics such as cut, wear, and dressing efficiency further demonstrates superabrasives prowess.
Cutting Efficiency: Superabrasives like Diamond and cBN require less power and force for cutting operations, ensuring efficient material removal.
Wear Resistance: Superabrasives demonstrate significantly higher wear resistance, leading to prolonged wheel life and reduced downtime when compared to conventional abrasives.
Dressing Efficiency: Superabrasives also excel when considering downtime for dressing since they maintain dressing efficiency over extended periods. In some cases, we have seen up to 20 times the parts per dress. With less frequent dressing comes more consistent performance. Plus, you’re only taking off a tenth of the material in dressing, so your wheel lasts much longer.
Cost Considerations
Superabrasives, with their many advantages, do come with a substantial up-front investment. Even so, many companies see sustainable returns.
Long-Term Value: Superabrasives offer enhanced productivity and cost-effectiveness that often results in lower cost per part over time.
Application Considerations: Recognizing that not every application warrants a superabrasive grinding wheel, factors such as machine tools, fluid compatibility, and work volume must be considered. Superabrasives are most cost effective in high volume, extremely demanding applications.
Expert Guidance
Thank you for joining us on this exploration of grinding wheel abrasives. If you would like help deciding which abrasive would work best to optimize your grinding process, don't hesitate to reach out to our engineering team at TheGrindingChronicles@CDTUSA.net. Until next time, check out additional insights and discoveries on other episodes of The Grinding Chronicles.