3D contours show steps and scallops

Problem category: Workpiece Quality

Cause: Step-over too large; tool contact angle to the surface too large; unsuitable cutter radius; wrong strategy (e.g. only Z-levels).

Bore tapered and out of tolerance

Cause: Bending of the boring bar; insufficient rigidity; incorrect position of the cutting edge; cutting forces too high.

Built‑up edge on cutting edge

Problem category: Tool Life

Cause: Unsuitable cutting speed. Oil content in coolant too low. Cutting speed and temperature at the cutting edge too low. Negative honing too large. No coating.

Burrs at entry and/or exit

Problem category: Workpiece Quality

Cause: Cutting edge not sharp enough. Feed rate too low for the chosen corner radius. Notch wear in the depth of cut area or chipping. Burr formation at the end of the cut.

Burrs or breakout at cross‑hole intersection

Problem category: Workpiece Quality

Cause: Unfavourable exit angle; no adjustment of cutting data; no deburring operation; chips remain in the intersection area.

Burrs or poor edge at shoulders

Problem category: Workpiece Quality

Cause: Unfavourable entry and exit; incorrect entering angle; feed too low in the exit zone; unsuitable edge preparation.

Chatter marks and poor bore finish

Problem category: Workpiece Quality

Cause: Feed rate too low; bar overhang too large; insufficient damping; incorrect insert distribution.

Chipping when drilling into a pre‑hole

Cause: Unstable conditions. TIR too high. Feed rate too high. Insufficient coolant flow (thermal cracks). Insufficient coolant supply (crazing cracks). Maximum allowable wear exceeded.

Chips pack in deep grooves

Problem category: Chip Handling

Cause: Feed too low for reliable chip breaking; groove too narrow in relation to tool width; unsuitable chipbreaker geometry.

Chips pack in deep holes

Problem category: Chip Handling

Cause: Cut lengths too long without chip evacuation; insufficient coolant pressure or volume; chip space too small; unsuitable cutting parameters.

Coolant foams or lubricates poorly

Problem category: Thermal & Power

Cause: Incorrect concentration; unsuitable coolant type; air ingress into the system; contaminated or aged emulsion.

Cutter teeth show thermal cracks and chipping

Problem category: Tool Life

Cause: Large temperature variations due to alternating wet/dry conditions; unsuitable coolant strategy; cutting speed too high in intermittent cuts.

Cutting edge breaks in interrupted cuts

Problem category: Tool Life

Cause: Cutting speed too high; geometry too sharp or not robust enough; wrong grade for intermittent cutting.

Diameter tapered over component length

Problem category: Workpiece Quality

Cause: Workpiece or tool deflection; insufficient support; cutting forces too high; unsuitable infeed strategy.

Drill breakage

Problem category: Tool Life

Cause: TIR too high. Unstable conditions. Insufficient spindle power. Chip packing. Feed rate too high. Excessive wear.

Drill skids on inclined/curved surface

Problem category: Workpiece Quality

Cause: No secure starting point; feed too high at entry; insufficient centering rigidity; unsuitable geometry.

Drill wanders; hole off‑position

Problem category: Workpiece Quality

Cause: No or insufficient centre drilling; unequal cutting edge lengths; sloping or uneven entry; feed too high at entry.

Even flank wear (preferred wear pattern)

Problem category: Tool Life

Excessive wear at chisel edge

Problem category: Tool Life

Cause: TIR too high. Cutting speed too low. Feed rate too high.

Fibrous surface; dimension not achieved

Cause: Chips break against the workpiece and leave marks on the machined surface. Fibrous surface due to excessive notch wear at the cutting edge Too high feed in combination with too small corner radius generates a rough surface.

High power consumption during cutting

Problem category: Thermal & Power

Cause: 1. Cutting speed (vc) too high. 2. Insufficient wear resistance of the grade. Central cutting edge: abrasive chips (workpiece material). Outer cutting edge: diffusion wear caused by high temperature (unfavourable for PVD).

High radial cutting forces

Problem category: Process Stability

Cause: Incorrect entering angle Corner radius too large Unsuitable corner radius or negative land Excessive flank wear at the cutting edge

High tangential cutting forces

Problem category: Process Stability

Cause: Insert geometry generates high cutting forces. Chip breaking is too aggressive, resulting in high cutting forces. Fluctuating or too low cutting forces due to small depth of cut. Tool is not positioned correctly. Tool instability due to long overhang. Unstable clamping, resulting in insufficient stiffness.

Hole bell‑mouthed at entry/exit

Problem category: Workpiece Quality

Cause: Unstable guidance of the drill; overhang too large; insufficient workpiece clamping; incorrect pilot hole.

Indentation at cutting edge; poor finish

Problem category: Chip Handling

Cause: Working temperature too high in combination with high pressure (feed and/or workpiece hardness). End result with excessive flank and/or crater wear.

Individual teeth wear faster than others

Problem category: Tool Life

Cause: Radial or axial run-out errors; excessive depth of cut; poor tool clamping; uneven engagement across the width of cut.

Insert breakage

Problem category: Tool Life

Cause: Cutting forces too high. Insufficient stability.

Lack of power

Problem category: Workpiece Quality

Cause: Power consumption in milling varies with: material removal rate, average chip thickness, cutter geometry and cutting speed.

Long chips wrap around tool/workpiece

Problem category: Chip Handling

Cause: Feed rate too low for the chosen geometry Depth of cut too small for the chosen geometry Corner radius too large Incorrect entering angle

Milled planes show steps or waviness

Problem category: Workpiece Quality

Cause: Insufficient axial run-out accuracy of the cutter; uneven engagement; unsuitable step-over strategy; vibrations.

Milled thread pitch error; screw jams or wobbles

Problem category: Workpiece Quality

Cause: Incorrect machine parameters (pitch, interpolation); wrong tool compensation; run-out or positioning errors.

Part breaks off uncontrollably / clamps tool

Cause: No relief groove or groove width too small; incorrect sequence in multiple-groove operations; insufficient clamping force.

Pip remains on workpiece after parting

Problem category: Workpiece Quality

Cause: Incorrect centre height or entering angle; uneven chip formation; incorrect cutting strategy in the final section of the cut.

Poor cutting edge condition

Cause: Unfavourable temperature (cutting speed). Geometry too negative. Adhesive workpiece material. Too little oil in the coolant.

Reamed bore bell‑mouthed or barrel‑shaped

Cause: Unsuitable pilot hole; incorrect feed; worn or incorrectly dimensioned reamer.

Reamer chips jam in bore

Problem category: Chip Handling

Cause: Chip load too high; insufficient lubrication; unsuitable flute space and guide geometry.

Scrap part due to machining fault

Problem category: Workpiece Quality

Cause: Insufficient stability. Machining with interrupted cut. Insufficient coolant supply. Feed too high or cutting speed too high/too low. Grade too wear-resistant (P-grade). Insert is worn.

Severe notch wear in titanium turning

Problem category: Tool Life

Cause: Tough, low thermal conductivity material with tendency to work hardening; depth of cut too small; unfavourable engagement conditions.

Spindle at power limit or stalls

Problem category: Process Stability

Cause: Chip cross-section too large; unsuitable strategy (e.g. full slotting instead of trochoidal milling); wrong tool dimension; machine too weak for chosen operation.

Strong BUE in stainless; poor surface/accuracy

Problem category: Tool Life

Cause: Tough, work-hardening material; cutting speed too low; unsuitable geometry; incorrect cooling.

Surface finish not acceptable

Problem category: Workpiece Quality

Cause: Unstable conditions. Uneven surface. Insufficient toughness of the grade. Insert geometry too weak. Insufficient coolant supply. Sand inclusions (cast iron).

Tap breaks in hole

Problem category: Process Stability

Cause: Core hole diameter too small; insufficient lubrication; cutting forces too high; chip packing in the flute.

Thin walls deflect; scoring and dimension errors

Problem category: Workpiece Quality

Cause: Cutting forces too high; insufficient support of the wall; incorrect machining sequence.

Thread flanks uneven; profile incorrect

Problem category: Workpiece Quality

Cause: Incorrect infeed strategy (e.g. purely radial infeed); infeed per pass too small; unstable clamping; wrong tool setting angle.

Thread flanks with built‑up edge or smearing

Problem category: Tool Life

Cause: Tough, adhesive material; cutting speed too low; unsuitable lubrication and cooling strategy; wrong cutting material.

Thread out of tolerance (core hole too small/large)

Problem category: Workpiece Quality

Cause: Incorrect core hole drilling; unsuitable tolerance class; tool wear; unstable system.

Tool creeps axially; depth out of tolerance

Problem category: Process Stability

Cause: Axial forces too high; insufficient clamping force of the holder; wrong clamping range of the collet; smooth shanks without form lock.

Turned shaft oval or polygonal (lobing)

Problem category: Workpiece Quality

Cause: Vibrations in the system; unstable workholding; loose clamping devices; uneven cutting forces.

Vibration and poor finish in narrow slots/pockets

Cause: Engagement too large at high overhang; insufficient stiffness of tool and workpiece; unfavourable toolpath strategy.

Vibration and poor surface despite correct data

Cause: Damaged or contaminated toolholder interface; corrosion or fretting at contact surfaces; incorrect tightening torque.