Overview of Sandvik CoroTurn 107 and 111 Systems
Sandvik Coromant’s CoroTurn 107 and CoroTurn 111 are two of the most widely used turning tool systems in CNC machining shops worldwide. Both offer precision-ground inserts with advanced chipbreakers, but they serve different application niches. This article provides a detailed comparison to help you choose the right system for your turning operations.
CoroTurn 107: The Precision Turning Standard
The CoroTurn 107 system is designed for precision turning with a focus on surface finish and dimensional accuracy. It uses positive-rake inserts with sharp cutting edges, making it ideal for finishing and light-to-medium roughing operations.
Key characteristics of CoroTurn 107:
- Insert type: Positive rake, precision-ground
- Primary applications: Finishing, semi-finishing, thin-walled components
- Typical feed range: fn = 0.05 to 0.4 mm/rev
- Depth of cut range: ap = 0.1 to 4.0 mm
- Insert sizes: 09, 11, 16 (ISO metric designation)
CoroTurn 111: The Heavy-Duty Productivity System
CoroTurn 111 is engineered for high metal removal rates in roughing and medium turning. It uses a robust insert clamping system with reinforced cutting edges that withstand heavy interrupted cuts and deep depths of cut.
Key characteristics of CoroTurn 111:
- Insert type: Negative to neutral rake, honed edges
- Primary applications: Roughing, heavy interrupted cuts, scale-bearing forgings
- Typical feed range: fn = 0.15 to 0.8 mm/rev
- Depth of cut range: ap = 1.0 to 10.0 mm
- Insert sizes: 12, 16, 19, 25
Grade Comparison for Both Systems
Both systems accept Sandvik’s full range of carbide grades. The most popular grades for steel turning are listed below with their recommended cutting parameters.
| Grade | ISO Class | Coating Type | Speed Range Vc (m/min) | Best Application |
|---|---|---|---|---|
| GC4325 | P15-P30 | Inveio CVD Al2O3 | 180-380 | Medium turning, general-purpose steel |
| GC4335 | P25-P40 | CVD Al2O3-TiCN | 130-280 | Roughing, interrupted cuts in steel |
| GC4225 | P10-P25 | CVD Al2O3-TiCN | 200-420 | Continuous finishing of steel |
| GC1125 | P10-P20, M10-M20 | PVD TiAlN | 150-350 | Sharp-edge finishing, stainless, thin walls |
| GC2220 | M10-M25, S10-S20 | PVD TiAlN | 80-220 | Stainless steel, duplex, superalloys |
Direct Comparison: CoroTurn 107 vs 111
| Parameter | CoroTurn 107 | CoroTurn 111 |
|---|---|---|
| Rake angle | Positive (15-20 deg) | Negative to neutral |
| Cutting force level | Low | High |
| Surface finish capability | Ra 0.4-1.6 um | Ra 1.6-6.3 um |
| Max feed rate | fn = 0.4 mm/rev | fn = 0.8 mm/rev |
| Max depth of cut | ap = 4.0 mm | ap = 10.0 mm |
| Interrupted cut resistance | Moderate | Excellent |
| Chip control at low feed | Excellent | Fair (needs fn > 0.15) |
| Tool life (steel, medium cut) | 35-55 min | 25-45 min |
| Holder rigidity requirement | Standard | High (large shank recommended) |
| Cost per edge | Higher (precision grind) | Lower (standard sintered) |
Cutting Parameters: Head-to-Head Test
Below are tested parameters for turning AISI 4140 (28-32 HRC) using both systems with GC4325 grade in CNMG 120408 configuration.
| Operation | System | Vc (m/min) | fn (mm/rev) | ap (mm) | MRR (cm3/min) | Tool Life |
|---|---|---|---|---|---|---|
| Semi-finish | CoroTurn 107 | 260 | 0.25 | 2.0 | 24.5 | 52 min |
| Semi-finish | CoroTurn 111 | 240 | 0.35 | 2.5 | 36.0 | 38 min |
| Roughing | CoroTurn 107 | 220 | 0.35 | 3.5 | 44.0 | 28 min |
| Roughing | CoroTurn 111 | 220 | 0.50 | 5.0 | 73.5 | 32 min |
When to Choose CoroTurn 107
Select CoroTurn 107 when:
- Tight tolerances (IT6-IT7) and fine surface finishes (Ra below 1.6 um) are required
- Machining thin-walled or slender components where cutting forces must be minimized
- Working with sticky materials like low-carbon steel (AISI 1010-1020) or austenitic stainless steel (304, 316L)
- Using Swiss-type lathes or small CNC lathes with limited spindle power (below 5 kW)
- Low-feed operations (fn below 0.15 mm/rev) where chip control is critical
When to Choose CoroTurn 111
Select CoroTurn 111 when:
- Maximum metal removal rate is the priority
- Cutting interrupted surfaces such as keyways, splines, or bolt-hole patterns
- Machining forgings or castings with scale, sand inclusions, or hard surfaces
- Working on heavy-duty lathes with rigid setups and high spindle power (above 15 kW)
- Depth of cut exceeds 4 mm consistently
Hybrid Approach: Using Both Systems
Many high-productivity shops use both systems on the same workpiece. A typical workflow involves:
- Roughing pass with CoroTurn 111, CNMG 160612, GC4335 grade, Vc=180 m/min, fn=0.6 mm/rev, ap=8 mm
- Semi-finishing with CoroTurn 111, CNMG 120408, GC4325 grade, Vc=250 m/min, fn=0.3 mm/rev, ap=2 mm
- Finishing pass with CoroTurn 107, DCMT 11T304, GC1125 grade, Vc=300 m/min, fn=0.15 mm/rev, ap=0.5 mm
This approach maximizes productivity while achieving final tolerances within IT6 and surface finishes of Ra 0.8 um or better.
Conclusion
Neither CoroTurn 107 nor 111 is universally superior. The 107 system excels in precision finishing with low cutting forces and excellent chip control. The 111 system dominates in heavy roughing where durability and metal removal rate matter most. Understanding your specific application requirements — tolerance, surface finish, material condition, machine rigidity, and production volume — will guide you to the right choice. For shops running diverse work, stocking both systems and switching by operation is the most productive strategy.
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