TURNING INSERT - NEGATIVE_CNMG
Caution
Product Description
Double-sided negative turning insert from Dormer Pramet: 80° rhombic CNMG 090304E-FM in grade T7325, an MT-CVD coated, functionally graded WC-Co carbide for fine to medium turning of stainless steels (ISO M10-M25).
9.525 mm inscribed circle, 3.18 mm thick, 0.4 mm nose radius, FM chipbreaker with rounded cutting edges.
- Designation according to the ISO 1832 indexable insert code system; ANSI equivalent: CNMG 321-FM:T7325.
- Indexing accuracy: ISO tolerance class M.
- Grade T7325 covers ISO application range M10-M25 and was developed to complement the existing Dormer Pramet T7335 grade.
- Cooling has a positive effect on tool life; use of coolant is recommended.
- Fits negative CN-type holders and boring bars with an insert seat for size 09 CNMG inserts, e.g. DCLN, PCLN, PCBN and PCKN styles; the approach angle is set by the holder.
- Select cutting speed, feed and depth of cut from the Dormer Pramet catalogue for the workpiece material and machine conditions, starting at the lower end of the recommended range.
- Before clamping, clean the insert seat and check that the insert sits flat; replace damaged shims or clamping parts.
- Country of origin: Czech Republic.
The Dormer Pramet CNMG 090304E-FM:T7325 (ANSI code: CNMG 321-FM:T7325) is a double-sided negative turning insert with an 80° rhombic shape, 0° clearance and indexing accuracy to ISO tolerance class M. It combines the FM chipbreaker with rounded cutting edges and grade T7325, the first-choice and most versatile Dormer Pramet grade for turning stainless steels.
Key Features
- Negative double-sided design with chipbreakers on both faces provides 4 cutting edges per insert.
- FM geometry for finishing to semi-roughing in continuous and slightly interrupted cuts.
- Medium-wide positive T-land strengthens the cutting edge, allowing light to medium feeds with lower cutting forces.
- Narrow, shallow chip groove forms smaller, more manageable chips and breaks chips over a wide range of feeds.
- Grade T7325: functional gradient WC-Co carbide substrate with a special MT-CVD coating containing textured alpha Al2O3.
- High cutting edge strength and resistance to crack formation give increased operational reliability, high performance and long tool life.
Applications
- Fine to medium turning of stainless steels (ISO M10-M25) on CNC lathes, with external holders or boring bars.
- Highly productive machining; also suitable for moderately unfavourable cutting conditions.
| Manufacturer | Dormer Pramet |
|---|---|
| Insert type | Negative turning insert, double-sided |
| Shape | C - 80° rhombic |
| Clearance angle | N - 0° |
| Tolerance class | M (ISO) |
| Insert design | G - fixing hole, chipbreaker on both faces |
| Chipbreaker | FM (rounded cutting edge, E) |
| Grade | T7325 |
| Substrate | Functionally graded WC-Co carbide |
| Coating | MT-CVD (with textured alpha Al2O3) |
| ISO application range | M10-M25 |
| Inscribed circle (IC) | 9.525 mm |
| Thickness (S) | 3.18 mm |
| Cutting edge length (L) | 9.7 mm |
| Nose radius (RE) | 0.4 mm |
| Fixing hole diameter (D1) | 3.81 mm |
| Number of cutting edges | 4 |
| ISO code | ANSI code | Grade | Chipbreaker | Inscribed circle IC (mm) | Thickness S (mm) | Cutting edge length L (mm) | Nose radius RE (mm) | Fixing hole D1 (mm) |
|---|---|---|---|---|---|---|---|---|
| CNMG 090304E-FM:T7325 | CNMG 321-FM:T7325 | T7325 | FM | 9.525 | 3.18 | 9.7 | 0.4 | 3.81 |
80° rhombic (diamond-shaped) negative insert with flat top and bottom faces that both carry the FM chipbreaker, and a cylindrical fixing hole through the centre. The side faces are perpendicular to the top face (0° clearance), so the insert can be turned over and both faces used. Cutting is done at the two 80° corners on each face, each with a 0.4 mm rounded nose radius.
- Inscribed circle diameter (IC): 9.525 mm
- Cutting edge length (L): 9.7 mm
- Insert thickness (S): 3.18 mm
- Corner radius (RE): 0.4 mm
- Fixing hole diameter (D1): 3.81 mm
- Included corner angle: 80°
- Clearance angle: 0°
Reading the ISO code CNMG 090304E-FM
| Code | Meaning |
|---|---|
| C | 80° rhombic shape |
| N | 0° clearance angle (negative insert) |
| M | Tolerance class M |
| G | Fixing hole, chipbreaker on both faces |
| 09 | Cutting edge length 9.7 mm |
| 03 | Thickness 3.18 mm |
| 04 | Corner radius 0.4 mm |
| E | Rounded cutting edge |
| FM | Chipbreaker for fine to medium machining |
| T7325 | Grade for stainless steels |
Choosing a chipbreaker in grade T7325 (CNMG)
- FM (this insert): fine to medium machining, continuous to slightly interrupted cuts.
- NMR: fine to heavy machining.
- SM: fine to heavy machining of stainless steels and super-alloys.
- RM, NRM: medium to heavy machining.
Choosing the grade by workpiece material
- Stainless steels (ISO M): T7325 is the first choice.
- Steels (ISO P): grades such as T9315, T9325 or T9415; PVD-coated grade T8430 for fine to medium machining.
- Mixed steel and stainless steel work: T9325 covers ISO P15-P35 and M10-M30.
Nose radius
The 0.4 mm radius gives low cutting forces and suits finishing and small depths of cut. For higher feeds and a stronger cutting corner, choose a larger radius such as CNMG 090308 (0.8 mm).