Troubleshooting in turning

• Feed is too low for the chosen geometry

• Increase feed
• Select an insert geometry with better chip breaking capabilities
• Use a tool with precision coolant

• Depth of cut is too shallow for the chosen geometry

• Increase depth of cut or select a geometry with better chip breaking capability

• Too big nose radius

• Select a smaller nose radius

• Unsuitable entering angle

• Select a holder with as large entering angle (lead angle) as possible.
  KAPR= 90° (PSIR =0°)

• Feed is too high for the chosen geometry

• Choose a geometry designed for higher feeds, preferably a single-sided insert
• Reduce feed

• Unsuitable entering angle

• Select a holder with as small entering angle (lead angle) as possible.
  KAPR= 45°–75° (PSIR 45–15°)

• Too small nose radius

• Select a larger nose radius

• The chips are breaking against the component and marking the finished surface

• Select a geometry which guides the chips away from the component
• Change entering angle
• Reduce depth of cut
• Select a positive tool system with a neutral angle of inclination

• Hairy surface is caused by excessive notch wear on the cutting edge

• Select a grade with better resistance to oxidation wear, for example a cermet grade.
• Reduce the cutting speed

• Feed is too high, in combination with a nose radius that is too small, a rough surface is generated

• Select a wiper insert or a larger nose radius
• Reduce feed

• The cutting edge is not sharp enough
• The feed is too low for the edge roundness

• Use insert with sharp edges, PVD coated inserts or ground inserts at small feed rates, < 0.1 mm/rev (0.004 in/rev)

• Notch wear at depth of cut, or chipping

• Use a holder with a small entering angle

• Burr formation at the end or start of cut

• End or start the cut with a chamfer or a radius when exiting/entering the workpiece

• Unsuitable entering angle

• Select a larger entering angle (lead angle). KAPR = 90°
  (PSIR = 0°)

• Nose radius is too large

• Select a smaller nose radius

• Unsuitable edge rounding, or negative chamfer

• Select a grade with a thin coating, or an uncoated grade

• Excessive flank wear on the cutting edge

• Select a more wear resistant grade or reduce speed

• Insert geometry creating high cutting forces
• Chip breaking is too hard, producing high cutting forces

• Select a positive insert geometry
• Reduce the feed or select a geometry for higher feeds

• Cutting forces vary or are too low due to small depth of cut

• Increase the depth of cut to make the insert cut

• Tool is incorrectly positioned

• Check the centre height

• Instability in the tool due to long overhang

• Reduce the overhang
• Use the largest possible bar diameter
• Use a Silent Tools™ or a carbide bar

• Unstable clamping leads to insufficient rigidity

• Extend the clamping length of the boring bar
• Use EasyFix™ for cylindrical bars

Flank wear
Preferable wear type in every application. Offers predictable and stable tool life.

• Cutting speed too high
• Too tough grade
• Insufficient wear resistance
• Hard inclusions in workpiece material

• Reduce cutting speed
• Select a more suitable grade depending on toughness demand or wear resistance

Notch wear

• Sticky and/or work-hardening materials
• Use a ~90° entering angle
  (~0° lead angle)
• Geometry is too negative

• Select a sharper edge
• Decrease entering angle
• Vary depth of cut

Crater wear

• Too high cutting speed and/or feed
• Chip breaker too narrow
• Chemical dissolution or abrasive wear
• Wear resistance too low

• Reduce cutting speed or feed
• Select a more wear resistant grade
• Select a more open/positive geometry

Plastic deformation
Depression Impression

• High heat load and pressure, cutting temperature too high
• Grade too tough/soft
• Lack of coolant supply

• Reduce heat and pressure load by reducing cutting speed and/or feed
• If edge depression, reduce feed first
• If flank depression, reduce speed first
• Select a more wear/heat resistant grade
• Select a more open/positive geometry
• Improve coolant supply

Built-up edge (B.U.E)

• Too low cutting temperature
• Sticky/smeary material
• Geometry too negative
• Coating too thick

• Increase cutting temperature by increasing speed
• Select a PVD-coated grade (less BUE on PVD-coatings)
• Select a more positive geometry

Flaking

• Smeary material
• Cutting speed too low
• Intermittent machining with coolant
• Coating too thick

• Increase cutting speed
• Turn off coolant
• Select a grade with thinner coating and better edge line security (PVD)

Chipping on edge

• Unstable conditions
• Grade too hard/brittle
• Coating too thick (CVD, leading to edge line flaking)

• Make the machine conditions more stable
• Select a tougher grade
• Select a stronger geometry
• Select grade with thinner coating (PVD)

Thermal cracks

• Varying cutting edge temperatures
• Intermittent cuts and coolant
• Grade is sensitive to heat shock variations
• Use of grade with thicker coating (CVD)

• Switch off coolant or apply coolant copiously to obtain an even temperature level
• Decrease cutting speed
• Select grade with thinner coating (PVD)

Breakage

• Excessive wear
• Wrong choice of grade (too tough/hard)
• Wrong cutting data

• Run shorter (time in cut) operations: check how wear begins and the dominant wear type
• Change cutting data
• Select a more suitable insert grade/geometry

Slice fracture - ceramics

• Excessive tool pressure

• Reduce feed
• Select a tougher grade
• Select an insert with a smaller chamfer, or use another geometry to change cutting force direction

Chipping outside cutting zone

• Chip jamming because of facing towards shoulder
• The chips are deflected against the cutting edge
• Not optimized feed or feed direction

• Change operation path (to avoid facing towards shoulder)
• Change feed
• Select a PVD-coated grade
• Select an insert geometry that alters the chip flow