Tool Life Expectancy Reference: How Many Parts Per Edge by Material and Operation
Knowing how long your insert should last is critical for production planning, cost estimation, and knowing when something is wrong with your process. This reference provides realistic tool life expectations in both cutting minutes and parts per edge for carbide inserts across all major material groups and operations. All values assume proper parameters, adequate coolant, and rigid setups.
Understanding Tool Life
Tool life is defined as the total cutting time (in minutes) before the insert reaches its wear limit. The ISO 3685 standard defines tool failure criteria:
| Wear Type | Failure Criterion | Measurement |
|---|---|---|
| Flank Wear (VB) | VB = 0.3 mm (general) or 0.2 mm (finishing) | Width of wear land on flank face |
| Crater Wear (KT) | KT = 0.06 + 0.3 × f (mm) | Depth of crater on rake face |
| Notch Wear | VB_max = 0.6 mm at depth-of-cut line | Maximum wear at notch location |
| Chipping / Fracture | Any visible edge damage | Visual inspection |
| Plastic Deformation | Visible edge rounding or nose depression | Visual / microscope inspection |
Turning Tool Life: Steel (ISO P)
| Material | ISO | Operation | Korloy Grade | Vc (m/min) | f (mm/rev) | ap (mm) | Expected Tool Life (min) | Parts Per Edge* |
|---|---|---|---|---|---|---|---|---|
| Low Carbon Steel | P10–P20 | Rough Turning | PC5300 | 300 | 0.35 | 3.0 | 25–40 | 80–150 |
| Low Carbon Steel | P10–P20 | Finish Turning | PC5300 | 420 | 0.15 | 0.5 | 40–70 | 200–400 |
| Medium Carbon (C45) | P20–P30 | Rough Turning | PC5335 | 260 | 0.30 | 2.5 | 20–35 | 60–120 |
| Medium Carbon (C45) | P20–P30 | Finish Turning | PC5335 | 370 | 0.15 | 0.5 | 35–60 | 150–300 |
| Alloy Steel (4140) | P30–P40 | Rough Turning | PC5400 | 200 | 0.25 | 2.5 | 18–30 | 50–100 |
| Alloy Steel (4140) | P30–P40 | Finish Turning | PC5400 | 300 | 0.12 | 0.5 | 30–50 | 120–250 |
| Hardened (45–55 HRC) | P40–P50 | Hard Turning | NC3225 / CBN | 130 | 0.12 | 0.5 | 15–25 (carbide) 60–120 (CBN) |
50–100 (carbide) 200–500 (CBN) |
* Parts per edge assumes a typical CNC turned part with 30–60 seconds of cutting time per part. Actual values vary significantly with part geometry.
Turning Tool Life: Stainless Steel (ISO M)
| Material | ISO | Operation | Korloy Grade | Vc (m/min) | f (mm/rev) | ap (mm) | Expected Tool Life (min) | Parts Per Edge |
|---|---|---|---|---|---|---|---|---|
| Austenitic SS (304) | M10–M20 | Rough Turning | PC215K | 180 | 0.25 | 2.5 | 15–25 | 40–80 |
| Austenitic SS (304) | M10–M20 | Finish Turning | PC215K | 260 | 0.12 | 0.5 | 25–45 | 100–200 |
| Austenitic SS (316L) | M20–M30 | Rough Turning | PC2507 | 150 | 0.22 | 2.0 | 12–22 | 35–70 |
| Duplex SS (2205) | M30–M40 | Rough Turning | PC2507 | 120 | 0.20 | 2.0 | 10–18 | 25–55 |
| Duplex SS (2205) | M30–M40 | Finish Turning | PC2507 | 180 | 0.10 | 0.4 | 20–35 | 80–150 |
Turning Tool Life: Cast Iron (ISO K)
| Material | ISO | Operation | Korloy Grade | Vc (m/min) | f (mm/rev) | ap (mm) | Expected Tool Life (min) | Parts Per Edge |
|---|---|---|---|---|---|---|---|---|
| Gray Iron (GJL-250) | K10–K20 | Rough Turning | KC5305 | 320 | 0.35 | 3.5 | 30–50 | 100–200 |
| Gray Iron (GJL-250) | K10–K20 | Finish Turning | KC5305 | 450 | 0.15 | 0.5 | 50–80 | 250–500 |
| Nodular Iron (GJS-500) | K20–K30 | Rough Turning | KC5335 | 230 | 0.30 | 3.0 | 22–38 | 70–140 |
| Nodular Iron (GJS-700) | K30–K40 | Rough Turning | KC5405 | 170 | 0.25 | 2.5 | 18–30 | 55–110 |
Milling Tool Life: Face Mills
| Material | ISO | Cutter Ø (mm) | Korloy Grade | Vc (m/min) | fz (mm/tooth) | ap (mm) | Tool Life per Edge (min) | Total Edges on Insert |
|---|---|---|---|---|---|---|---|---|
| Low Carbon Steel | P10–P20 | 80 | PC5300 | 300 | 0.20 | 3.0 | 30–50 | 4–8 |
| Medium Carbon Steel | P20–P30 | 80 | PC5335 | 250 | 0.18 | 3.0 | 25–40 | 4–8 |
| Alloy Steel | P30–P40 | 63 | PC5400 | 200 | 0.15 | 2.5 | 20–35 | 4–8 |
| Austenitic Stainless | M10–M20 | 63 | PC215K | 170 | 0.14 | 2.5 | 15–28 | 4–8 |
| Gray Cast Iron | K10–K20 | 100 | KC5305 | 350 | 0.20 | 3.0 | 35–55 | 4–8 |
| Aluminum 6061 | N10 | 80 | NCM325 | 600 | 0.18 | 4.0 | 60–100 | 4–8 |
Super Alloy & Hard Material Tool Life
| Material | ISO | Operation | Korloy Grade | Vc (m/min) | f (mm/rev) | ap (mm) | Tool Life (min) | Parts Per Edge |
|---|---|---|---|---|---|---|---|---|
| Titanium Ti-6Al-4V | S10–S20 | Rough Turning | PC3545 | 60 | 0.15 | 2.0 | 10–20 | 20–50 |
| Titanium Ti-6Al-4V | S10–S20 | Finish Turning | PC3545 | 100 | 0.08 | 0.3 | 15–30 | 40–80 |
| Inconel 718 | S20–S30 | Rough Turning | PC3545 | 40 | 0.12 | 1.5 | 8–15 | 15–35 |
| Inconel 718 | S20–S30 | Finish Turning | PC3545 | 70 | 0.07 | 0.3 | 12–22 | 30–60 |
| Hardened Steel (55 HRC) | H20 | Hard Turning | NC3225 | 120 | 0.10 | 0.3 | 12–20 | 30–60 |
| Hardened Steel (60 HRC) | H20–H30 | Hard Turning | CBN | 150 | 0.08 | 0.2 | 40–80 | 100–250 |
Taylor Tool Life Equation
Tool life follows the Taylor equation, which relates cutting speed to tool life:
Vc × Tⁿ = C
Where:
Vc = cutting speed (m/min)
T = tool life (minutes)
n = Taylor exponent (material-dependent)
C = Taylor constant (material-dependent)
| Material | Taylor Exponent (n) | Effect of 20% Speed Increase |
|---|---|---|
| Low Carbon Steel (P10) | 0.25–0.35 | Tool life drops ~50–60% |
| Alloy Steel (P30) | 0.20–0.30 | Tool life drops ~55–70% |
| Austenitic Stainless (M20) | 0.15–0.25 | Tool life drops ~65–80% |
| Gray Cast Iron (K20) | 0.25–0.40 | Tool life drops ~45–60% |
| Titanium (S10) | 0.10–0.20 | Tool life drops ~75–90% |
| Inconel (S20) | 0.10–0.18 | Tool life drops ~80–95% |
Key takeaway: In super alloys, even a small increase in cutting speed can destroy tool life. In steel, you have more room to push speed. Always prioritize stable tool life over maximum speed in production.
Tool Life Optimization Checklist
| If Tool Life Is Too Low… | First Check | Then Try |
|---|---|---|
| Flank wear reaching limit too fast | Speed too high? Grade too soft? | Reduce Vc 10–15%, switch to harder grade |
| Chipping on cutting edge | Interrupted cut? Grade too hard? | Switch to tougher grade (higher ISO sub-group) |
| Crater wear on rake face | Speed too high for CVD? | Reduce Vc, ensure adequate coolant flow |
| Built-up edge (BUE) | Speed too low? Chipbreaker too flat? | Increase Vc, switch to sharper chipbreaker, use PVD |
| Plastic deformation | Speed + feed too high? Coolant failing? | Reduce Vc, check coolant concentration and flow |
| Notch wear at depth-of-cut line | ap hitting work-hardened surface? | Vary ap slightly, use tougher grade |
Cost Per Part Calculation
To calculate your actual cost per part based on tool life:
Cost per edge = Insert Price / Number of Cutting Edges
Parts per edge = Tool Life (min) / Cutting Time per Part (min)
Insert cost per part = Cost per edge / Parts per edge
Example: A Korloy CNMG 120408 insert at $6.50 with 4 usable edges, turning C45 steel:
Cost per edge = $6.50 / 4 = $1.625
Tool life = 30 min, cutting time per part = 0.45 min
Parts per edge = 30 / 0.45 = 67 parts
Insert cost per part = $1.625 / 67 = $0.024 per part
Tool Life Summary by Material Difficulty
| Material | Difficulty Rating | Typical Tool Life (roughing) | Typical Tool Life (finishing) |
|---|---|---|---|
| Aluminum | 1/10 (Easiest) | 60–100 min | 100–200 min |
| Gray Cast Iron | 3/10 | 30–50 min | 50–80 min |
| Low Carbon Steel | 3/10 | 25–40 min | 40–70 min |
| Medium Carbon Steel | 4/10 | 20–35 min | 35–60 min |
| Alloy Steel | 5/10 | 18–30 min | 30–50 min |
| Austenitic Stainless | 7/10 | 15–25 min | 25–45 min |
| Duplex Stainless | 8/10 | 10–18 min | 20–35 min |
| Titanium | 9/10 | 10–20 min | 15–30 min |
| Inconel / Superalloys | 10/10 (Hardest) | 8–15 min | 12–22 min |
Optimize your tool life and reduce cost per part. At hooguu.com, we provide Korloy inserts at competitive prices with free technical support. Our application engineers can analyze your process and recommend grade, chipbreaker, and parameter changes to maximize your parts per edge. Contact us today for a tool life audit.
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