An Innovative Abrasives Technology: Engineered Shaped Ceramic Grain

Engineered Shaped Grain Delivers Unbeatable Grinding Performance headline with an image of an operator grinding with a Norton RazorStar disc

 

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s manufacturing process requirements evolve and become more challenging in both the U.S.A. and abroad, abrasive products for metalworking applications must also evolve to meet new criteria, while keeping operator health and safety a top priority. This is true in a range of industries such as foundry, fabrication, aerospace, machining, oil & gas, medical, automotive, and more. High productivity, speed, and long abrasives life are all key for today’s grinding applications for all types of materials.

 

Historically, operators performed right angle grinding primarily on carbon steel using small grinding wheels with fused aluminum oxide grain to remove welds or bevel parts. Grinding wheels were used for medium to large welds because of the improved performance and life when compared with using the fiber discs that were available at that time.

 

Zirconia-alumina abrasive grain was the next advancement to reduce grinding time and increase abrasives’ life. When zirconia-alumina was incorporated into a fiber disc, operators now preferred a fiber disc over the conventional grinding wheel for weld removal. While zirconia grain advanced grinding technology, it required high forces to remain sharp. Thus came the ceramic grain, which required less grinding force, further reduced grind times, and increased disc life. The continued advancement of newer ceramics and topcoats (i.e. supersize – grinding aid layers) pushed the boundaries of grinding even further, improving product performance. Today, the next era of abrasive products is taking grinding to the next level with engineered shaped ceramic grain. These grains not only improve performance on carbon steel, but also on challenging materials such as aluminum, Inconel, stainless, and titanium.

 

Impetus for New Abrasive Development

 

Today, the market expects abrasives manufacturers to offer greater value through new technology. Metalworking professionals need a longer life abrasive that grinds quickly, requiring low force to use. The new abrasive product should not only work on carbon steel, but also on a variety of other metal alloys, and the product should result in lower overall process costs.

 

Seeking industry-leading product life, cut rate, and grinding efficiency requires the collaboration of applications experts, research & development, sales force, and suppliers. A team was formed to develop new abrasives technology in order to produce the best performing abrasive products on the market.

 

The multifaceted team first defined the key performance indicators based on the needs and desires of the market. Creating the new coated abrasive products began with an equally challenging development of a novel shaped ceramic grain. The abrasives R&D team collaborated with their internal grain supplier to revolutionize their grain production. Shaped ceramic grains required an entirely new manufacturing process. The collaborative team first brainstormed grain shapes that would be appropriate to manufacture; be processible in coated abrasive production; and most importantly, be highly efficient machining-cutting tools. The top contending shapes were then manufactured on a pilot scale. These prototype grains were quickly screened in existing abrasive product architectures. After a few cycles of grain evaluation, a new engineered shape shone brightest with razor sharp tips.

The process of developing new abrasives technologies

 

With the grain shape determined, the next challenge was designing entirely new coated abrasive products, optimizing performance with the new grain. Product development consisted of many iterative learning cycles to continuously improve product performance. The team designed, manufactured, tested, and evaluated prototypes. These learnings would be used to start the next cycle over again: design, manufacture, test, and evaluate. Rinse and repeat, over 100 designs evaluated (and multiple patents along the way) to get the most out of each component of the products until they were meeting or surpassing all performance indicators. This design was then tested at many customers both domestically in the United States and abroad to gain real grinding feedback. A few more design cycles later and the new abrasives featuring a novel engineered shaped ceramic grain in fiber discs, quick-change discs, and belts, not only met the internal performance metrics, but also the approval of valued customers.

 

Engineered Shaped Ceramic Grain: Optimized, Novel Shape, and Chemistry

 

New engineered shaped ceramic abrasive grains have been formulated to avoid the common struggles of conventional ceramic abrasives when grinding challenging materials. Optimizing both abrasive grain and abrasive architecture results in longer life, especially on hard-to-grind materials, achieved with less heat buildup, higher cutting efficiency, and broader versatility than any previous abrasive products. Each engineered shaped grain is precisely dimensioned to a patented shape to ensure uniform, efficient cutting and predictable fracture behavior. Meanwhile, the unique star shape comprised of nano-scale highly pure alumina crystals promotes self-sharpening as the grain micro-fractures during grinding.

 

Norton RazorStar benefits

 

In contrast, conventional grains have completely unpredictable fracture behavior and are either too dull to avoid fracture, leading to tip erosion, rubbing, dulling, and metal swarf adhesion, or these grains are too weak to fracture on the desired micro-scale, leading to unpredictable large-scale fracture, fast grain wear, and poor abrasive product life.

 

Comparing the grain in RazorStar to that in the competitive product

 

Precisely Designed Architecture

 

The innovation behind engineered shaped ceramic grain abrasive products is not just the premier shaped grain but also the optimized abrasive design. The layered architecture of backing, resins, grains, and grinding aids has been constructed to further promote efficient grinding with the engineered shaped grain. Grains are adhered to the backing in a precise spatial density to control the force per individual grain. This tuned force per grit leads to highly efficient self-sharpening resulting in longer life at lower energy consumption. To fully achieve the efficiency of both the individual grain and the group as a whole, a new technology was developed with characteristics of the adhering resin layer locking the grains as they are projected into the product during production. This results in the greatest level of grain orientation (standing grains) in the abrasives market.

 

Diagram showing the higher percentage of upright grains in RazorStar belts as compared to other belts

Norton RazorStar™ products feature a very high concentration of grains that are oriented in an upright position, so the abrasives are ready to cut and aggressively perform at their sharpest point.

 

Height map of the competitive shaped grain Height map of the shaped grain in RazorStar

Pictured above is a height map of the competitive shaped grain belt (left) vs. RazorStar belt (right). There are more standing grains in the RazorStar belt due to the highly upright orientation.

 

Chart comparing the standing grain in fiber discs for RazorStar compared to the competitive product Chart comparing the standing grain in belts for RazorStar compared to the competitive product

 

Grinding Performance

 

Norton | Saint-Gobain Abrasives set out to meet the new metalworking abrasives criteria by developing a new, breakthrough abrasives technology, and during the process set a new benchmark for significantly improved operator comfort, higher productivity, and improved grinding efficiency.

 

By combining a self-sharpening novel shaped grain with precisely designed abrasive architecture and the highest grain orientation, unprecedented grinding performance is now possible with Norton RazorStar™ belts, fiber discs, and quick-change discs.

 

RazorStar belts are versatile and cool cutting, and very suitable for automation/ robotics, powerpack, or off-hand metal removal applications. The belts are especially well suited for applications requiring medium-high pressure where the goal is to remove a high amount of metal as fast as possible with as few abrasive belts as possible.

 

RazorStar belt’s cool grinding is well suited for sensitive alloys and hard-to-grind materials where metal burn must be avoided. The efficiency of the grain to cut versus plow material, combined with the grinding aid in the resin coating layers which inhibit metal loading, results in long belt life and protects against workpiece discoloration.

 

 

RazorStar fiber discs

RazorStar fiber discs use the same technology as the belts and provide beveling, weld removal, and stock removal. RazorStar fiber discs work on typical carbon steel welds, but are exceptionally productive on stainless, superalloys, and other exotic materials. Due to the engineered shaped grain and the abrasive architecture, only one Norton RazorStar disc is typically needed for a range of materials versus requiring two different discs with conventional ceramic abrasives.

 

Another advantage of the efficient grinding behavior of RazorStar fiber discs is that operators can apply less pressure to the work, for an ergonomic and user-friendly solution which reduces fatigue. The reduced pressure also extends the life of the right angle grinder and maximizes performance by reducing heat that causes metal capping on the work.

 

Internal testing of the Norton RazorStar fiber disc compared to a standard ceramic disc demonstrated that the newly engineered shaped ceramic grain removed nearly 100% more material with less disc wear and required less power per gram to remove, extensively improving operator and machine efficiency.

 

In one test with carbon steel, the new engineered shaped ceramic grain discs removed 2,000 more grams than the standard ceramic grain discs. The performance of RazorStar discs far exceeds conventional fiber discs by removing more material at a faster cut rate.

Chart showing the material removed in the process of carbon steel fiber disc grinding using products with different abrasive grains.

The RazorStar fiber discs also offer operators other noticeable advantages over grinding wheels. For large welds, RazorStar discs demonstrated a faster cut rate and more material removed per second, with less vibration and noise compared with grinding wheels.

 

Ready to reach for RazorStar? Follow the tips below to get the most out of your grinder and discs.

 

grinder and disc use

 

The new RazorStar abrasives featuring engineered shaped ceramic grain can be run on the same off-hand grinders that currently use standard ceramic abrasive products. As always, the grinder still needs to be strong enough for the application. If the application is light pressure, a less expensive lower amp grinder can be used. If the application is more demanding, a higher amp grinder is required. Usually, the latter has a higher upfront cost, but over the life of the grinder, the user will save costs by purchasing fewer grinders, and operation time will be decreased because greater pressure can be applied.

 

It is advisable to use a backup pad that is correctly rated for the grinder, and guards on the grinder should always be used to prevent operator injury. RazorStar discs (and all abrasives discs) should be stored in rooms with temperatures ranging from 60 to 80 degrees Fahrenheit and humidity levels between 35 and 50%.