Page 22 - MetalForming May 2013

Real Wheel Productivity and Cost
Grinding Operations:
Here’s a close evaluation of abrasive-grinding performance and cost when grinding in job shops and production-manufacturing operations.
crushed and then sorted by grit size and shape to be used in abrasive tools such as grinding or cutting wheels and sanding products. Other grains are manufactured using molding technol- ogy, which produces precision-shaped grains that offer a more uniform struc- ture and size.
Precision-shaped grains can be made into different shapes and sizes depending on the market needs. They generally cut quickly and perform well in precision metal-removal applica- tions requiring tight tolerances and fine scratch patterns. However, it is important to consider the application at hand, as some characteristics of pre- cision-shaped grains—such as bond quality, grain orientation, grain hard- ness and friability—can make them less effective for rough grinding jobs.
Wheel manufacturers often expend considerable effort to develop a pro- prietary mixture of grains that will pro- vide optimal performance. For example, in certain grinding- and cutting-wheel lines, Norton offers a proprietary blend of ceramic-alumina and zirco- nia-alumina grains. These proprietary grains microfracture as they break
BY DEBBIE GASPICH
Job shops as well as production- manufacturing operations will find that the abrasive products outfitted to their hand-held power tools can play a crucial role in increasing productiv- ity. Often viewed as a negligible expense, abrasives comprise on average less than 2 percent of the total cost of a fabricating operation. However, most shops fail to realize that 10 to 15 per- cent of their labor is consumed in metal-fabrication and finishing opera- tions. So, rather than simply consider- ing the direct cost on the distributor’s product invoice, a more accurate meas- ure of productivity would be to look at the true total process cost, or the total
Debbie Gaspich is director of product management, North America, for Nor- ton Abrasives; www.nortonabrasives.com.
work to be performed with abrasives. The abrasive grain is a cutting tool, and the type and quality of the grain can determine the true value of the performance of an abrasive tool. Per- formance grains deliver benefits such as higher stock-removal rates, increased product life, reduced metallurgical damage and less wear and tear on grinding machines. And, these grains are ergonomically friendly. All of these factors work to minimize the total cost of the grinding process. The most-com- petitive production operations evaluate these factors when making their pur-
chasing decisions.
Breaking Down the Grains
Abrasive grains can be made by sev- eral manufacturing methods. Some are made in large ingots in furnaces,
20 MetalForming/May 2013
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