| Cause | Detailed Analysis | Targeted Solutions |
|---|---|---|
| 1. Excessive Cutting Temperature | At high cutting speeds, the temperature in the cutting zone rises excessively, leading to carbide softening and coating oxidation or peeling. | ✅ Process Adjustment: Reduce spindle speed (n) or cutting depth (ap), and slightly increase feed per tooth (fz) to lower local heat accumulation. ✅ Cooling Optimization: Apply high-pressure coolant (HPC) or minimum quantity lubrication (MQL) to improve heat dissipation. ✅ Tool Upgrade: Use high-temperature-resistant coatings (TiAlN, AlTiSiN, nACo) for better thermal stability. |
| 2. Cutting Parameters Too Large | Excessive ap, ae, or fz creates high cutting forces that exceed the tool’s strength limit, causing edge failure. | ✅ Reduce axial and radial depth of cut (ap, ae); prioritize increasing feed rate moderately to maintain productivity while controlling torque. ✅ For thin-wall parts or long tool overhangs, use multi-step machining (layered cutting) to reduce impact load. ✅ Adopt adaptive or constant-load toolpaths (e.g., high-efficiency milling) to minimize sudden force changes. |
| 3. Improper Coating or Substrate | Poor coating adhesion or incorrect coating type accelerates wear. Carbide substrates with low toughness tend to chip easily. | ✅ Select coatings according to workpiece material: - Aluminum alloys: DLC/CrN anti-adhesive coating or uncoated sharp edge. - Steel: TiAlN, AlTiN, or TiSiN coatings. - Stainless steel: nACo or AlTiSiN for thermal stability and oxidation resistance. - Titanium alloys: TiAlCrN or TiB₂ coatings for anti-adhesion and high heat resistance. ✅ If chipping occurs frequently, choose a tougher carbide grade (e.g., K20 or K30). |
| 4. Work-Hardened Material | Hardened surface increases cutting force and edge fatigue. | ✅ Use sharp edges with positive rake angles to reduce cutting force. ✅ Lower feed per tooth, maintain continuous cutting to avoid impact loading. ✅ For heavily hardened surfaces (e.g., quenched steel, cold-work mold steel), pre-mill the surface or use ceramic/PCBN cutters. |
| 5. Long Tool Overhang or Vibration | Vibration induces cyclic impact on the cutting edge, accelerating fatigue. | ✅ Shorten tool overhang; use anti-vibration (damping) holders. ✅ Check spindle and holder concentricity; use shrink-fit or HSK holders for high rigidity. |
| 6. Poor Cooling or Chip Evacuation | Overheated chips adhere to the cutting edge, causing secondary wear. | ✅ Use directional coolant jets or air blow to quickly remove heat and chips. ✅ For deep cavity machining, use through-coolant tools or high-pressure coolant (HPC) systems. |
Record the relationship between material type, cutting speed, feed rate, and tool life to create a practical experience chart.
Example Reference:
| Material | Cutting Speed (Vc, m/min) | Feed per Tooth (fz, mm/tooth) |
|---|---|---|
| Carbon Steel (45#) | 120–180 | 0.03–0.06 |
| Stainless Steel (SUS304) | 60–90 | 0.02–0.04 |
| Aluminum Alloy | 250–400 | 0.05–0.10 |
Summary:
To significantly extend tool life and prevent chipping/rounding:
