The most common applications for wide grooves or turning between shoulders are multiple grooving, plunge turning or ramping. All three methods are roughing operations and have to be followed by a separate finishing operation.
A rule of thumb is that if the width of the groove is smaller than the depth – multiple grooving should be used and vice versa for plunge turning. However for slender components ramping may be used.
Axial turning – surface finish
Due to the wiper effect achieved in axial turning with CoroCut it is possible to generate a high quality surface finish. Ra value below 0.5 can be generated, and also high bearing ratio is achieved resulting in the elimination of a grinding operation.
| Comparison between CoroCut (A) and conventional turning tools (B). For comparison of surface finish achieved, see the graph. |
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| Surface finish comparison |  |
Surface finish,
Ra μm | |
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| TNMG 160404 |
| TNMG 160408 |
| CoroCut – 5 mm RM |
| CoroCut – 4 mm TF |
| CoroCut – 6 mm TM |
Feed, mm/r |
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Depth of cut/feed rate
When high feeds are used in conjunction with low depth of cut (DOC), or low feeds with high DOC, sufficient deflection of the tool will occur to give clearance for the front cutting edge.
However, where low feeds and low DOC are combined the axial forces may be insufficient to give clearance. This may cause rubbing and hence vibration.
Solutions
| 1) | If possible raise DOC or feed rate. |
| 2) | Use TF geometry with a concave cutting edge which will limit contact. |
| 3) | By changing to a holder with longer Ar , will affect the result. |
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Recommended grade and cutting data
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First choice geometry for turning of grooves is TF for low feed and TM for higher feeds.
Starting grade is GC1125.
Cutting speed 150 m/min, radial feed 0.12 mm/r and axial feed 0.2 mm/r. |
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Case stories
| Machining specification
Operation: Grooving
Material: Stainless steel, CMC 05.2
Machine: CNC turning lathe
Tool holder: LF123K32-2525BM
Insert: N123K2-0600-0004-TF
Grade: GC1125
| Cutting data | Competitor | Sandvik Coromant |
| Cutting speed: | 120 m/min | 150 m/min |
| Radial/axial feed: | 0.15/0.2 mm/r | 0.2/0.3 mm/r |
| Time in cut: | 0.50 min | 0.298 min |
| Components: | 156 pcs | 183 pcs |
Tool life +15%
Productivity +68%
Annual time saving 91 hours |
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