Cutting-edge sharpness is the most important factor determining penetration and material action on a motor grader's moldboard. Caterpillar says the operator is responsible for keeping the edge sharp. Rolling the blade back when mixing material and sweeping roads will whet the edge.
Use the thinnest cutting edge that material and conditions will allow. This will improve material rolling action and increase moldboard down force. It also requires less horsepower to push the blade through the cut, which reduces fuel consumption and tire wear. Thick or dull cutting edges require more down pressure. It increases a lot of negatives: rim pull requirement, tire slip, force on the frame, driveline torque loads, and cutting-edge temperature.