Engine Turbine Disc Processing Solution

3.1 Blank preparation

• Forging process: isothermal forging or powder metallurgical forging to ensure the density and mechanical properties of the material.
• Blank form: disc-shaped blank, reserved sufficient processing allowance (usually 3-5mm one-sided).

3.2 Rough processing

• Objective: Remove most of the margin to form the basic shape of the turbine disc.
• Key Process:
  • Turning: Use high-power CNC lathes to process outer circles, end faces, and inner holes, and use layered cutting to reduce cutting force.
  • Milling: Use plug milling or cycloid milling to reduce tool load.
• Tool selection:
  • Carbide-coated cutters (such as TiAlN coatings) or ceramic cutters for improved wear resistance.
  • Large feed milling cutter reduces cutting depth and increases feeding capacity to improve efficiency.
• Cooling method: high-pressure cooling (5-20MPa), improve heat dissipation and flush chips.

3.3 Semi-finishing

• Objective: To refine the structure and reserve a uniform margin for finishing (0.3-0.5 mm on one side).
• Key process:
  • Precision Turning: Machining of datum features such as stops and positioning surfaces of the turbine disk to ensure positioning accuracy for subsequent machining.
  • Milling of tongue and groove/leaf root: adopt 5-axis linked machining center, and initially form the complex shape through layered milling or electric discharge machining (EDM).
• Tool selection: Carbide end mills or molding tools, with the tool radius compensation function of the CNC system to improve accuracy.
• Inspection: Coordinate Measuring Machine (CMM) to inspect key dimensions and adjust machining parameters.

3.4 Finishing

• Objective: To meet the design accuracy and surface quality requirements.
• Key process:
  • Precision turning/grinding: process the inner/outer diameter, end face and thrust face of the turbine disk with accuracy control at μm level and surface roughness Ra≤0.4μm.
  • Tongue and groove finishing: High precision 5-axis machining centers or electro-chemical machining (ECM) are used to ensure the profile accuracy and surface integrity of the fir-tree shaped tongue and groove.
  • Hole processing: Processing bolt holes, weight reduction holes, etc., using gun drilling or internal cold drilling to ensure the straightness and surface quality of the holes.
• Tool selection:
  • Diamond tools (for non-ferrous metals) or ceramic tools (for high-temperature alloys) to improve machining surface quality.
  • Specialized forming tools to reduce forming errors.
    Cooling and
• lubrication: Micro lubrication (MQL) or oil mist cooling to reduce cutting heat and minimize tool wear.