Boost Manufacturing Profitability with Optimized Cutting Tool Maintenance

In every manufacturing operation, selecting the right cutting tool is as vital as the skill of the operator. A sharp, well‑maintained tool not only delivers precision but also drives throughput, directly impacting profitability.

Sharpening by grinding remains the most effective method for restoring worn tools. Conventional wheels—made of aluminum oxide or silicon carbide—are quick to dull, prone to glazing, and can damage the tool’s surface through heat and metallurgical changes. Super‑abrasive cubic boron nitride (CBN) wheels, on the other hand, offer superior performance, especially for high‑speed and super‑alloy steels.

• CBN grains exhibit 55× the thermal conductivity of aluminum oxide, four times the abrasive resistance, and twice the hardness.
• Longer wheel life even at high material‑removal rates.
• Minimal thermal damage thanks to a cool cutting action.
• Consistent, burr‑free edges that retain hardness.
• Greater grinding productivity—less downtime for wheel conditioning and fewer gauge adjustments.

CBN wheels also maintain strength above 10,000 °C and do not chemically react with steel, enhancing fatigue resistance and extending tool life.

Before switching from an aluminum oxide wheel, ensure your grinding system can harness CBN’s advantages. Key considerations include:

• Machine rigidity—tight spindle bearings, close‑fitting slides, and a stable spindle speed.
• Horsepower—hard materials demand more power to achieve the same material removal.
• Coolant application—directly to the work‑wheel interface for optimal cooling.

Wheel Selection

Choosing the right CBN wheel hinges on several factors:

Bond type: Resin‑bond wheels suit most cutter grinding, while electroplated wheels are ideal for form grinding.

Grit size: When substituting an aluminum oxide wheel, refer to the table below for appropriate grit ranges.

Concentration: Levels of 75–100 yield optimal material‑removal rates and cost efficiency.

Grinding parameters also influence performance. Both wet and dry grinding are viable, but each has nuances:

• Dry grinding with resin‑bond CBN wheels is effective at low feed rates to avoid tool burn‑through.
• Wet grinding—using straight or heavy‑duty water‑soluble oils—offers superior cooling and lubrication.

For machines with sufficient power and rigidity, creep‑feed, single‑pass grinding is recommended, delivering the highest productivity, longest wheel life, and best surface finish. Conventional multi‑pass grinding remains a solid choice for many operations.

Recommended wheel speeds:

• Dry grinding: 3,000–4,500 SFPM (15–23 m/s).
• Wet grinding: 5,000–6,500 SFPM (25–33 m/s).

Maintain a constant traverse feed rate. For roughing cuts, aim for ~0.002 in (0.05 mm) depth; finish cuts should be 0.001–0.005 in (0.01–0.02 mm). Spark‑out passes are unnecessary with CBN wheels if the grinder is properly set.

Mount CBN wheels on a high‑quality adapter, keep them assembled as a unit, and true the wheel to within 0.001 in (0.02 mm) run‑out. Use an appropriate truing device and dress the wheel on the machine where it will operate.

Modern grinding machines now integrate automation and flexibility, offering increased precision and productivity. Using CBN wheels for end mills, milling cutters, hobs, and other hardened tools can cut grinding costs by 20–50 % while improving edge quality and tool life.

About the Author

Dr. Anil Srivastava, Manager of Manufacturing Technology at TechSolve in Cincinnati, brings over 30 years of research, teaching, and industry experience in machining and grinding. A Ph.D. in Mechanical Engineering from the Indian Institute of Technology, Kanpur, he has led numerous projects on machining optimization, cost‑effective material removal, cutting tool performance, and metalworking fluids. Currently, he manages a $6 million, three‑year NIST‑ATP project focused on intelligent grinding process optimization.