Engineers designing products for the aerospace market are faced with a variety of challenges. Constant pressure exists for tighter part tolerances, better part quality, greater throughput, and higher productivity. The high temperature and abrasion resistance of today’s aerospace materials can lead to high tool wear and a slow material removal rate with conventional machining techniques such as turning and milling. Precision grinding with advanced abrasive products such as those that contain Norton patented Vitrium3 bond, delivers an efficient solution.
The Norton Vitrium3® bond is a revolutionary new bond platform that provides enhanced performance to meet the demands of the aerospace precision grinding market. Vitrium3 bonded wheels are capable of grinding at high speeds while maintaining precise profile shapes and cool cutting temperatures. Available in custom, made-to-order solutions, wheels with Vitrium3 bond excel in a number of precision grinding applications, including creepfeed and surface grinding of high-strength materials like the nickel alloys used in turbine rotor blades and nozzle guide vanes.
The key to the superior characteristics of Vitrium3 bond is its exclusive chemistry and grain adhesion science that holds abrasive grains in place for a precise amount of time with an exact amount of applied force per grain. This unique chemistry provides Vitrium3 bond with improved strength that allows less bond material to provide the same holding power on individual abrasive grains. High bond strength and a low bond-to-abrasive ratio grant Vitrium3 bond grinding wheels the array of benefits mentioned above vs. standard wheels, including the ability to hold precise profiles, maintain cool cutting temperatures, and grind at high speeds.
Vitrium3 bond grinding wheels are comprised of a matrix of abrasive grains that are held together by glass bonds with engineered spacing, known as controlled porosity. The bonds of the abrasive are formed through vitrification of the bond material as the product is fired in a kiln. Vitrification occurs as the clay materials of the bond melt in the high-temperature environment of the kiln and reform as bridges between the grains of abrasive. Grinding wheels with vitrified bonds are rigid and hold their profiles well. They remain strong at high temperatures, although their brittle nature can lead to failure in applications where the wheel is exposed to shock or impact. They also have a high porosity, facilitating heat transfer as coolant flows through gaps in the matrix to keep temperatures low.
1) Precise Profile
One of the key benefits that grinding wheels featuring Vitrium3 bond offer is the ability to hold precise profiles. The high-strength bond between abrasive grains enhances wheel form and corner holding. Intricate part geometries can be cut without requiring wheel dressing to regenerate the profile. Productivity is improved due to less time spent dressing the wheel, and costs are lowered due to reduced dresser replacement expense and less abrasive waste.
In testing Norton engineers found that the profile breakdown radius of Vitrium3 bond wheels was significantly reduced after five cycles compared to a standard wheel. For a theoretical material removal rate of 15 mm3/mm/s, Vitrium3 bond wheels had a profile breakdown radius of only 1 mm compared to 2.3 mm for standard wheels, demonstrating superior profile holding characteristics of Vitrium3 bond.
2) Cool Cutting
Another fundamental benefit provided by Vitrium3 bond wheels is the ability to maintain cool workpiece temperatures during grinding operations. Vitrium3 bond features thinner bond posts between abrasive grains that expose more grain surface area and minimize friction between the bond material and the part. Increased space between grains improves coolant flow and chip clearance. Furthermore, a lower bond-to-abrasive ratio results in lower grinding forces on the part, reduced heat build-up, less workpiece burn, and lower power consumption.
Testing demonstrated that for a given material removal rate, 15 percent less power was needed compared to a standard wheel. In addition, for a given level of power consumption, Vitrium3 wheels removed 20 percent more material. This translates into less generation of heat for a cooler cut, preventing workpiece burn.
3) High Speed
The third major benefit offered by Vitrium3 bond wheels is their ability to operate at high speeds due to their high structural strength provided by strong bonds between abrasive grains. Grinding at high speed improves productivity by increasing stock removal and feed rate. Compared to standard wheels, Vitrium3 bond products were found to be 20 percent stronger in tests, allowing even softer grades to be rated for high-speed operation.
The benefits of Vitrium3 bond technology are available in a variety of Norton products, from Quantum ceramic alumina wheels to those made with conventional aluminum oxide. In one case study, Norton Quantum X ceramic wheels featuring Vitrium3 bond were compared to a competitor’s ceramic-blend wheels on a creepfeed grinder machine processing turbine blades made of nickel alloy René-series material. The Vitrium3 bond wheels reduced cycle time from six minutes to less than three minutes and increased the number of parts processed per wheel from 325 to 500 pieces, resulting in substantial annual cost savings.
The Vitrium3 bond platform offers a revolutionary new chemistry that is lowering process costs by reducing cycle times with improved cutting efficiency and cut rate. Delivering the tight part tolerances and high part quality that engineers require, Vitrium3 bond wheels offer high throughput and productivity in aerospace precision grinding applications.
For more information, visit Norton | Saint-Gobain Abrasives.