Parameter adjustment strategies for CNC turning of superalloys

The parameter adjustment strategy for CNC turning of high-temperature alloys needs to be comprehensively considered from aspects such as tool selection, optimization of cutting parameters, cooling and lubrication, and clamping methods. The following are the specific strategies:

Tool selection and geometric parameter adjustment: High-temperature alloys have large cutting forces, high hardness, and severe work hardening. Tools must possess high strength, high red hardness, wear resistance, and toughness. It is recommended to use hard alloy, ceramic or PCBN tools, and apply high-temperature resistant coatings such as TiAlN and TiSiN to enhance the wear resistance and cutting performance of the tools. In terms of tool geometry parameters, a larger positive rake Angle (10° to 20°) should be adopted to reduce cutting force and temperature, a moderate relief Angle (8° to 12°) to reduce friction, and a small fillet of the cutting edge (0.02 to 0.1 mm) should be maintained to prevent chipping of the tool.

Optimization of cutting parameters

Cutting speed: When cutting high-temperature alloys, the cutting temperature is high. The appropriate cutting speed should be selected based on the thermal stability of the material. During rough machining, the cutting speed can be controlled at 20 to 40 meters per minute. During finish machining, the cutting speed can be appropriately increased to 40 to 60 meters per minute, but it is necessary to avoid it being too high, which may cause the tool to overheat and the material to oversinter.

Feed rate: The selection of feed rate should be based on the cutting speed and tool diameter to ensure a reasonable cutting depth and avoid tool breakage due to excessive load. During rough machining, the feed rate can be controlled at 0.2 to 0.4 millimeters per revolution. During finish machining, the feed rate should be reduced to 0.05 to 0.1 millimeters per revolution.

Cutting depth: The control of cutting depth should be matched with the cutting speed and feed rate to avoid excessive cutting depth causing tool vibration and workpiece deformation. During rough machining, the cutting depth can be controlled at 2 to 6 millimeters, and during finish machining, it should be reduced to 0.2 to 1 millimeter.

Cooling and lubrication: When cutting high-temperature alloys, it is necessary to pay attention to cooling and lubrication to lower the cutting temperature and reduce tool wear. Emulsions containing extreme pressure additives, kerosene and oleic acid mixtures and other cutting fluids should be selected, and it should be ensured that they can fully cover the cutting area to achieve the best cooling effect. If hard alloy cutting tools are used, the cutting fluid must be injected in large quantities continuously to prevent the blade from cracking due to uneven temperature.

Clamping method: During the turning process of high-temperature alloy workpieces, they must rotate along with the spindle. Correct clamping can ensure that the workpiece is in the correct position within the machine tool and does not loosen or fall off under the action of cutting force. For thin-walled parts, three-jaw or four-jaw clamping methods should be avoided to prevent deformation caused by radial force on the parts. Process blocks can be added in combination with the structure of the parts, and parts can be clamped by means of pressure plates or supporting inner holes, etc., effectively avoiding deformation caused by clamping.