Common Fluting Mistakes — and How to Fix Them

Flute Polish or Flute Burnish?
There is an increasing need for high-quality carbide mills and drills with polished flute faces. Your customers are demanding a surface grinding tool that has a shiny flute, evacuates a metal chip better, and runs at faster speeds.

Sometimes your customer just wants your tool to look like the “other guy’s” tool. Unfortunately, a burnished flute face can be mistaken for true polish. Toolmakers have the challenge of making a cost-effective tool that has great performance and a great finish on the flute face.

Common Fluting Mistakes
Some toolmakers turn to hybrid wheels that grind the flute in no time, but these grinding wheels really don’t polish all that well.

To improve appearances and achieve a smooth finish, a lot of toolmakers use nonwoven products to polish after fluting. But do flute polishing cloths really polish, or do they just burnish the surface?

For a Quality Flute Polish
For a flute cleaning and polishing that really penetrates the surface, you have to remove some material to get through the grind lines leftover after flute grinding.

A resin bonded grinding wheel can give you a finish that is as good or better than nonwoven polishing products, but the resin bonded wheel also removes material from the flute face, taking out subsurface damage.

Resin bond is made by mixing abrasive grit with a phenolic resin. The resulting compound is molded to shape before being baked in an oven. This produces a grinding wheel that's tough, with the resilience to take impacts without shattering. By adding copper and other fillers to the resin base, grinding wheel manufacturers can tailor the properties of the finished grinding wheel to a wide variety of applications.

With resin bond, you can make a tool that not only looks just as good as the “other guy”, but also is actually better quality than the other guy. Resin-bonded superabrasive grinding wheels provide:

• Shock-resistance

• Excellent surface finish

• Low maintenance

The Extra Effort Sets You Apart
The right wheel can help you polish up your act. CDT’s resin bond flute polishing wheel performs as good as it looks — producing a quality tool that shows. We offer resin bond polishing wheels to work in oil or emulsion on all CNC cutter grinders. These grinding wheels can run at high speeds and are available in grits as fine as 1200 or more based on finish requirements.

Grinding wheel manufacturers have years of experience and there are few fluting applications we haven't encountered. Our engineers can help you get the right grinding and polishing solution for your particular application.

Why Use Plated Diamond or Cubic Boron Nitride Tools?

Layering metal parts via electrolysis with special substances that improve their strength or appearance and protect parts from oxidation and corrosion is called electroplating. Typically less than .05 millimeters thick, coatings applied during the plating process are either metallic, diamond, or cubic boron nitride. Decorative objects such as jewelry or tableware are usually plated with silver or gold while steel and iron items are plated with zinc, chromium, nickel or tin. However, grinding tools require cubic boron nitride or diamond coatings to optimize their functioning, provide better cutting action and deter rapid deterioration of tools. 

Advantages of Electroplated Diamond Tools

Tools sent through an electroplating process that coats them with a diamond layer cleaved by a tough nickel alloy retain their precise proportions and original structure throughout their working life. Unlike resin bond or metal bond diamond products involving diamond particles that have been cached in bond and joined together by embedded resin or metal binder, electroplating facilitates the protrusion of diamond fragments to extend beyond the bond matrix. This further provides electroplated diamond tools with the exceptional ability to cut freely and rapidly without generating excessive heat. Less heat generation means better grinding efficiency, reduced risk of cracks or burns on the workpiece's surface and a significant decrease in equipment energy consumption.

Electroplated diamond tools are well-suited to process:

• Abrasive or hard non-metallic entities such as asphalt, stone, ceramics, concrete, semiconductor materials and glass.

• Non-ferrous metals (copper, aluminum and their alloys) and pliable but tough materials (resin and rubber, for example).

Since diamonds react with iron, cobalt, nickel, chromium and vanadium under elevated temperatures produced during grinding actions, diamond tools should not be used to process common steels and tough alloy steels. For work involving these materials, electroplated cubic boron nitride tools are recommended.

Advantages of Electroplated Cubic Boron Nitride Tools

Considered the best technological advancement made for facilitating grinding of superalloy and hardened ferrous materials, cubic boron nitride is second to diamonds on the hardness scale and offers nearly five times the abrasion resistance afforded by traditional abrasives. Electroplated CBN tools also provide the following additional benefits not found in any other electroplated tools:

• Remarkable thermal conductivity and chemical resistance

• Enhanced surface integrity for grinding hardened cobalt-based superalloys as well as nickel and hardened alloy steels

• Eliminates the expense of post heat-treat grinding operations

• Produces polished surface finishes by providing taut dimensional management of tools to users

• Creates no bit-dulling grit

The ability to induce nanostructuring of carbon boron nitride has allowed engineers to further increase the hardness of CBN by incorporating the Hall-Petch Effect, which describes the "tendency for hardness to intensify as grain size is decreased". In addition, carbon boron nitride's chemical resistant and strong thermal stability properties make it well-suited to machine ferrous materials that cannot be machined by electroplated diamond tools.