Plated CBN for Aerospace
Commercial airline travel may have taken a dramatic hit during the pandemic, but a rebound for the aerospace industry has already begun. 2021 marked the first all-civilian flight into space, and the possibilities this presents are especially exciting.
The mechanics of producing aircraft to safely transport people in such harsh conditions, however, is particularly challenging. Modern jet engines depend on superalloys to handle combustion temperatures of 1400ºC or more. These high-performance nickel-based materials have very high temperature stability, which makes machining components like turbine vanes extremely challenging. The solution is to use plated CBN wheels. Here’s why.
AEROSPACE DEMANDS
The aerospace industry asks a lot from their high-precision grinding tools. Specifically, aerospace grinding wheels must:
Remain hard at high temperatures
Be chemically inert to resist chemical reactions between grinding wheel and the nickel alloys
Provide excellent size control throughout a production run
Be available in complex forms
Not damage the workpiece – no burning or microcracking
Minimize residual stresses in the finished workpiece
Missing from this list is wheel life. While grinding wheel durability is important for Nickel based alloy grinding, it is less of a consideration for aerospace applications since their production runs are generally shorter than other industries like automotive. In this respect, plated grinding wheels provide a perfect middle ground.
Plated wheels are longer lasting than conventional abrasives, and they are capable of being refurbished through replating to extend their use. On the flip side, a plated wheel does not require the downtime for wheel dressing that a longer lasting Vitrified CBN wheel needs to maintain optimal performance. This makes plated wheels particularly well suited for applications with smaller lot sizes that don’t need an especially long life.
All of these considerations make plated CBN wheels an excellent option for aerospace applications.
ADVANTAGES OF CBN GRINDING TECHNOLOGY
As the hardest known substance, diamond might seem the obvious choice for grinding exceptionally hard materials. However, it doesn't perform so well at temperatures over 700ºC as it tends to react chemically with the material and deteriorates due to oxidation at higher temperatures. It's also vulnerable to attack by some of the chemicals found in grinding coolants, which reduces wheel life.
The alternative to diamond is Cubic Boron Nitride (CBN). This is a man-made or synthetic abrasive material that's not as hard as diamond but is harder than anything else. Unlike diamond, it retains its hardness at elevated temperatures. CBN offers superior resistance to chemical attack when grinding ferrous metal alloys. It exhibits no affinity to iron and doesn’t alter the material properties like Diamond does.
WHY PLATED WHEELS?
An electroplated grinding wheel has a single layer of superabrasive tightly bonded by a metallic layer to a solid metallic core. This has several advantages:
The bond material is below the tops of the grains, creating a free-cutting wheel that removes material rapidly with low power consumption, and helps keep interface temperatures down.
Good thermal conductivity helps take heat away from the grinding zone.
Wheel forms are readily achievable by machining needed geometries onto the metallic cores.
Worn wheels can be stripped and re-plated, making them an economical choice.
Costly dressing systems and rotary dressers aren’t needed, thus simplifying and lower capital expenditure on equipment.
THE AEROSPACE PROBLEM-SOLVER
Plated CBN grinding wheels are used extensively in aerospace. They perform well on exceptionally hard superalloys, providing high material removal rates coupled with excellent dimensional control throughout a production run.
The engineers at Continental Diamond Tool Corporation have extensive experience developing tools that can hold up to the rigorous demands of aerospace production. Contact us for a free grinding wheel analysis and quote.