Introduction To Edge Preparation

Tool edge preparation, in recent years has been universally recognized as one of the four main ingredients required in successful cutting tool manufacturing. These four ingredients include (1) tool substrate composition (tool base material), (2) tool geometry, (3) proper coating (if required) and (4) edge preparation. Over the past 20 years R&D efforts have focused mainly on the first three of the four ingredients, with vast resources being expended in these areas to develop more reliable and repeatable processes. In comparison the fourth ingredient, tool edge preparation, has been neglected when one looks at the progression of technological developments in this area.

Proper selection and application of cutting tool edge preparation is one of the basic ingredients for a successfully manufactured and optimum performing cutting tool. In today’s high technology manufacturing environment cutting edge preparation is fast becoming a necessity on all cutting tools manufactured of cemented carbide, ceramic, PCBN and PCD. The picture below illustrates the wide variety of tooling that requires edge prep in today’s demanding manufacturing environments.

The demands put on the cutting tool industry by its customers, using new high-tech machining equipment while facing the requirements of manufacturing with an increasing list of exotic materials, are high. With the new materials bombarding the industry and the ability for CNC machines to run in a "flat-out" untended environment, the performance demands are increasing on cutting tools. The need to produce more predictably performing tools is paramount to the industry and no one expects that trend to change.

Edge defects are present in nearly all tools prior to edge prep. The defects are the result of die flash after pressing, EDM processing and grinding. Some of these defects are illustrated in the pictures below. Although microscopic in size such defects lead to erratic tool performance and premature tool failure. These defects must be eliminated if one is to achieve optimum tool performance.

Die Flash

The tool edge preparation process, when administered properly, adds strength to the tool cutting edge, lengthens usable tool life, minimizes the propensity of the edge to chip, improves part quality and consistency, and enhances work piece surface finish. Some of the edge preparation options currently used by the tool manufacturer are up sharp (no edge prep after grinding), radius or waterfall hone shapes, T-Land (or K-Land), and T-land + hone. The most widely used edge preparation that exists in industry today is the radius and waterfall hone shapes. These edge preps are applied in a variety of sizes based on cutting tool size and application. Edge prep is not limited to application of indexable style tooling. It is required on most cemented carbide round tools, brazed steel shank tools, PCD and PCBN tools, and single/multiple edge cemented carbide form tools. While T-Lands (or K-Lands) are ground on to the tool edge, edge hones are applied to cutting tools in a variety of methods. These processes include vibratory honing, honing by hand with diamond stones, mass media honing, slurry honing, honing inserts with media impregnated rubber wheels, dry blasting, wet blasting, tumbling and brush honing with abrasive media impregnated filaments.

Today the process of cutting tool edge honing still remains an art for most tool manufacturers. The conventional honing processes available today are highly prone to over-working the corners of the tool and they can be difficult to control tool-to-tool because incoming part condition can vary. More often than not, the honing process is still guided by the best educated guess scenario limited by machine variability and operator expertise.

With Conicity Technologies this all changes, we have taken edge preparation to the next level, making it a science. Now the technology and equipment exists using the nylon abrasive filament brush technique to overcome nearly all the current processing problems and to produce a tool that will yield optimum performance in any given operation or application. The following pictures illustrate just a few of the tool types that Conicity can apply the EMG™ edge prep to, for more examples please look in the Image Library section of our website.