Cutting conditions

Feed rate
Spindle Speed
Radial cutting depth
Axial cutting depth
…
CUTTING
CONDITIONS
BACHELOR OF ENGINEERINGBACHELOR OF ENGINEERING
MANUFACTURING TECHNOLOGIESMANUFACTURING TECHNOLOGIES
CUTTING CONDITIONSCUTTING CONDITIONS
by Endika Gandarias

2by Endika Gandarias
Dr. ENDIKA GANDARIAS MINTEGI
Mechanical and Manufacturing department
Mondragon Unibertsitatea - www.mondragon.edu
(Basque Country)
www.linkedin.com/in/endika-gandarias-mintegi-91174653

3
CONTENTS
BIBLIOGRAPHY
CUTTING TOOLS
CUTTING PARAMETERS
CUTTING FLUIDS
SELECTION OF CUTTING CONDITIONS
GLOSSARY
by Endika Gandarias

4
BIBLIOGRAPHY
BIBLIOGRAPHY
by Endika Gandarias

5
The author would like to thank all the bibliographic references and videos that
have contributed to the elaboration of these presentations.
For bibliographic references, please refer to:
• http://www.slideshare.net/endika55/bibliography-71763364 (PDF file)
• http://www.slideshare.net/endika55/bibliography-71763366 (PPT file)
For videos, please refer to:
• www.symbaloo.com/mix/manufacturingtechnology
BIBLIOGRAPHY
by Endika Gandarias

6
CUTTING TOOLS
CUTTING TOOLS
by Endika Gandarias

7
CUTTING TOOLS
by Endika Gandarias
(HSS)
VIDEOVIDEO

8
CUTTING TOOLS
by Endika Gandarias

9
CUTTING TOOLS
by Endika Gandarias
Temperature [ºC]
Hardness[HRC]
1550
1400
1300
900
800
Ceramic
CBN
Carbide
(Hard metal)
Diamond
HSS
ºC

10
Feed [mm/rev]
Cuttingspeed[m/min]
50
CUTTING TOOLS
by Endika Gandarias

11
Solid tool Brazed insert Mechanically clamped insert
TOOL GEOMETRY
Turning
CUTTING TOOLS
by Endika Gandarias
VIDEO

12
CUTTING TOOLS
by Endika Gandarias
TOOL GEOMETRY
Turning RAKE FACE
Front Clearance (or end-relief) angle
Major (or side) cutting edge
Minor (or end) cutting
edge
Front or back rake angle
Nose (or corner) radius
MAJOR CLEARANCE (FLANK
OR RELIEF) FACE
Minor (or end)
cutting edge angle
MINOR CLEARANCE
(OR FLANK) FACE
Side rake angle
Major (or side or lead) cutting edge angle
Side clearance (or relief) angle
Major cutting
edge angle
Minor cutting
edge angle
RAKE FACE
CLEARANCEF
ACEClearance angle
Rake angle
Side clearance
angle
Side rake angle
VIDEO

13
CUTTING TOOLS
by Endika Gandarias
TOOL GEOMETRY
Milling
Flat
End Mill
Ball nose
End Mill
Corner radius
End Mill
END MILLING CUTTERS PERIPHERAL AND FACE MILLING CUTTERS
Shell
End Mill
Side and Face
cutter
Single and double
angle cutter

14
TOOL GEOMETRY
CUTTING TOOLS
by Endika Gandarias
Drilling
Solid carbide drill
Chisel edge
Main cutting
edge
Rake face
Major
flank faceMargin
Drill diameter
Web
thicknessMajor
flank face
Major
cutting edge
Rake face
Point angle
Minor cutting
edge
Helix
angle
Point angle
140°
High Speed Steel (HSS)
Point angle
118°
VIDEO

15
TOOL INSERT
Main cutting edge
design
Cheap-breaker
macrogeometry
Geometry for small
cutting depths (ap)
Rake angle 20°
Main facet 5°
Tip cutting edge design
Cheap-breaker
macrogeometry
Cutting edge
reinforcement of 0,25 mm
CUTTING TOOLS
by Endika Gandarias
VIDEO
Insert design

16
CUTTING TOOLS
by Endika Gandarias
Coated carbide tools
Ceramics
CBN (Cubic Boron Nitride)
Polycrystalline diamond
TOOL INSERT
Insert material types
Cermet
Non-coated carbide tools

17
TOOL INSERT
CUTTING TOOLS
by Endika Gandarias
VIDEO
POSITIVE
Rake angle
NEGATIVE
Increased tool insert resistance.
Higher cutting forces.
Shorter chip length.
Clearance angle = 0º.
Double side inserts.
Lower cutting forces.
Longer chip length.
Clearance angle > 0º.
Used for internal machining.
Clearance angle
Clearance angle always > 0º.

18
TOOL INSERT
CUTTING TOOLS
by Endika Gandarias
Lead angle / Entering angle
Entering angle
Lead angle
Side Rake angle
 Same advantage discussed for
rake angle, applies to side rake
angle.
 When rake angle is positive so is
side rake angle, and vice versa.

19
TOOL INSERT
CUTTING TOOLS
by Endika Gandarias
Nose radius and Nose angle Chipbreaker
Each insert has an
appliation area.
Groove type Obstruction type
Nose radius Nose angle

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TOOL INSERT
CUTTING TOOLS
by Endika Gandarias
Insert grade
VIDEO VIDEO VIDEO
VIDEO

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TOOL INSERT
CUTTING TOOLS
by Endika Gandarias
Insert fabrication
Raw material Crushed
Spray drying
Carbide powder
Ready to be pressed
Cobalt
Tungsten
carbide
Titanium
Tantalum
Niobium
Powder fabrication VIDEO

22
TOOL INSERT
CUTTING TOOLS
by Endika Gandarias
Insert fabrication
Pressing force
20 - 50 t
Upper and lower
die
Die and
center pin
Pressing

23
TOOL INSERT
CUTTING TOOLS
by Endika Gandarias
Insert fabrication Sintering
Sintering duration: 8 hours
Temperature between 1200 - 2200 °CInserts trays
Insert contraction
(18% in all directions,
50% in volume)

24
TOOL INSERT
CUTTING TOOLS
by Endika Gandarias
Insert fabrication Insert grinding
Higer and lower face Free profiling Profiling
Beveling, negative facet Peripheral
Bisel
Faceta
neg.

25
TOOL INSERT
CUTTING TOOLS
by Endika Gandarias
Insert fabrication Insert grinding
ER Treatment
(Edge Roundness)
W/H proportion depends on
the application

26
TOOL INSERT
CUTTING TOOLS
by Endika Gandarias
Insert fabrication Chemical Vapor Deposition (CVD) coating
- Large coating thickness.
- Mechanical wear resistance (TiCN).
- Thermal & chemical resistance (Al2O3).
TiCN
Al2O3
Substrate
Inserts trays
CVD oven

27
TOOL INSERT
CUTTING TOOLS
by Endika Gandarias
Insert fabrication Physical vapor deposition (PVD) coating
PVD oven
TiN
Substrate
- Thin coating thickness.
- Sharp cutting edge.
- Good edge toughness.
- Used in all monoblock rotating tools.
- Can be used with soldered tips.

28
TOOL INSERT
CUTTING TOOLS
by Endika Gandarias
Insert fabrication Visual inspection, marking, packaging
Visual inspection
Marking
Distribution
Labelling
Packaging

29
CUTTING PARAMETERS
CUTTING PARAMETERS
by Endika Gandarias

30
 SELECTION CRITERIA:
Make the highest profit considering the technical requirements.
 OPERATIONS:
– ROUGHING: It aims to remove as much as possible material from the workpiece for as
short as possible machining time. Quality of machining is of a minor concern.
– FINISHING: The purpose is to achieve the technical requirements (i.e., dimensional,
surface and geometric tolerances). Quality is of major importance.
In order to make most profit the most relevant variables are:
• Cutting time.
• Cutting tool expenditure.
Machining parameters that most affect the above variables are:
• Cutting speed (Vc)
• Feed (fz, fn, F)
• Radial and axial depth of cuts (ap, ae)
ROUGHING FINISHING
Vc
fn


fz


F
CUTTING PARAMETERS
by Endika Gandarias

31
DEFINITION: Relative linear speed at the contact point between tool and the workpiece.
Vc · 1000 N =
π · Dm
CUTTING PARAMETERS: TURNING
1. Cutting Speed (Vc)
by Endika Gandarias
N
Vc: Cutting speed (m/min)
N: Spindle speed (rpm)
Dm: machined diameter (mm)
VIDEO
VIDEO
VIDEO
VIDEO

32
Given the following parameters calculate
the spindle speed for each diameter:
Cutting speed Vc = 120 m/min
Diameter D1 = Ø 50 mm
Diameter D2 = Ø 80 mm
VC x 1000
π x d
N =
N1
N2
by Endika Gandarias

33
F [mm/min]
DEFINITION: Relative movement between the workpiece and the tool.
fn [mm/rev]
IN
TURNING
FEED PER
REVOLUTION
(fn)
→
2. Feed
3. Cutting depth (ap)
FEED PER REVOLUTION
F = fn·N
FEED RATE
or
FEED PER MINUTE
by Endika Gandarias
F
ap
ap
ap

34
MACHINE
WORKPIECE
MATERIAL
TOOL MATERIAL OPERATION
Vc
(m/min)
fn
(mm/rev)
Ap
(mm)
TURNING
MACHINE
STEEL
HIGH SPEED STEEL
(HSS)
Turning and facing
D 30 – 40
A 40 - 50
D 0.1– 0.25
A 0.02/ 0.1
D 0.75-2
A 0.2-0.8
Parting and grooving 10 – 15 0.02 – 0.1
Threading 10 Thread pitch According to formula
Drilling 18 Manual
Knurling 10
Boring
D 20 – 30
A 30 - 40
D 0.1– 0.25
A 0.02/ 0.1
D 0.75-2
A 0.2-0.8
HARD METAL
Turning and facing
D 80 – 100
A 100 - 120
D 0.1– 0.25
A 0.02/ 0.1
D 0.75-2
A 0.2-0.8
Threading 40 - 50 Thread pitch According to formula
Drilling 30 – 40 Manual
Boring
D 70 – 90
A 90 - 110
D 0.1– 0.25
A 0.02/ 0.1
D 0.75-2
A 0.2-0.8
ALUMINIUM
HIGH SPEED STEEL
(HSS)
Turning and facing
D 40 – 60
A 60 - 80
D 0.1– 0.25
A 0.02/ 0.1
D 0.75-2
A 0.2-0.8
Threading 15 Thread pitch According to formula
Drilling 30 Manual
Knurling 20
Boring
D 30 – 50
A 50 - 70
D 0.1– 0.25
A 0.02/ 0.1
D 0.75-2
A 0.2-0.8
HARD METAL
Turning and facing
D 150 – 180
A 180 – 200
D 0.1– 0.25
A 0.02/ 0.1
D 0.75-2
A 0.2-0.8
Parting and grooving 80– 100 0.04 – 0.1
Threading 50 – 60 Thread pitch According to formula
Drilling 60 – 80 Manual
Boring
D 140 – 170
A 170 - 190
D 0.1– 0.25
A 0.02/ 0.1
D 0.75-2
A 0.2-0.8
by Endika Gandarias
D: Roughing operation
A: Finishing operation
CUTTING PARAMETERS: TURNINGORIENTATIVECUTTINGTABLEFOREXERCISES

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SURFACE ROUGHNESS:
Surface finish depends on:
• Tool nose radius
• Feed per revolution (fn)
WIPER INSERTS:
Advantages:
Productivity ↑
by Endika Gandarias
VIDEO

36
by Endika Gandarias
TOOL CENTRE HEIGHT

37
VIBRATION
_ +
Vibration
by Endika Gandarias
Round
R
90º
S
80º
C
80º
W
60º
T
55º
D
35º
V
_
+
Vibration
ER: Edge Rounding
GC: Ground coated inserts
VB: Flank wear
_
+
Strength

38
VIBRATION
They can reduce machining vibration in turning, milling or
drilling.
VIDEO
– Diameters starting from Ø > 10mm.
– Maximum overhang value 14 × Ø.
by Endika Gandarias
Dampened tool
Undampened tool
SSV technique may reduce or eliminate chatter.
VIDEO
VIDEO
Dampened tools
Spindle Speed Variation (SSV)

39
CUTTING PARAMETERS: MILLING
by Endika Gandarias
N
N
Vc · 1000 Vc: Cutting speed (m/min)
N = N: Spindle speed (rpm)
π · Dc Dc: Tool diameter (mm)
VIDEO

40
Feed per tooth (fz): It defines the chip thickness, and so, the load that
the tool is subjected to.
Feed per revolution (fn): It defines the tool displacement per tool
revolution.
Feed rate or Feed per minute (F): It defines the tool movement speed.
fn = fz·z  z tooth number (flute number)
F = fn·N = fz·z·N  N spindle speed
IN
MILLING
FEED PER
TOOTH
(fz)
→
2. Feed
by Endika Gandarias
fn
F
VIDEO

41
As there are greater tooth breakage chances
during tooth entry and exit, in facing operations
the following tool size and positioning are
recommended.
 ap: axial depth of cut
 ae : radial depth of cut
3. Cutting depth
Better size
Better positioning
by Endika Gandarias
VIDEO

42by Endika Gandarias
MACHINE
WORKPIECE
MATERIAL
Vc
(m/min)
fz
(mm/tooth*rev)
Ap
(mm)
Ae
(mm)
MILLING
MACHINE
STEEL
HIGH SPEED
STEEL
(HSS)
Face milling
D 20 - 25
A 25 - 30
0.05 – 0.1
0.01 – 0.05
D 1-2
A 0.2-0.5
D (~2/3)Ø
A (~2/3)Ø
Side milling
D 20 - 25
A 25 - 30
0.05 – 0.1
0.01 – 0.05
D (50%-80%)Ø
A (50%-80%)Ø
D (10%-25%)Ø
A (5%-10%)Ø
Other milling
D 15 - 20
A 20 - 25
0.05 – 0.1
0.01 – 0.05
HARD METAL
Face milling
D 80 - 100
A 100 – 120
0.05 – 0.1
0.01 – 0.05
D 1-2
A 0.2-0.5
D (~2/3)Ø
A (~2/3)Ø
Side milling
D 80 - 100
A 100 – 120
0.05 – 0.1
0.01 – 0.05
D (50%-80%)Ø
A (50%-80%)Ø
D (10%-25%)Ø
A (5%-10%)Ø
Other milling
D 70 - 90
A 90 – 100
0.05 – 0.1
0.01 – 0.05
ALUMINIUM
HIGH SPEED
STEEL
(HSS)
Face milling
D 50 - 70
A 70 - 90
0.05 – 0.1
0.01 – 0.05
D 1-2
A 0.2-0.5
D (~2/3)Ø
A (~2/3)Ø
Side milling
D 50 - 70
A 70 - 90
0.05 – 0.1
0.01 – 0.05
D (50%-80%)Ø
A (50%-80%)Ø
D (10%-25%)Ø
A (5%-10%)Ø
Other milling
D 40 - 60
A 60 - 70
0.05 – 0.1
0.01 – 0.05
HARD METAL
Face milling
D120 - 150
A 150 – 180
0.05 – 0.1
0.01 – 0.05
D 1-2
A 0.2-0.5
D (~2/3)Ø
A (~2/3)Ø
Side milling
D120 - 150
A 150 – 180
0.05 – 0.1
0.01 – 0.05
D (50%-80%)Ø
A (50%-80%)Ø
D (10%-25%)Ø
A (5%-10%)Ø
Other milling
D100 - 130
A 130 – 150
0.05 – 0.1
0.01 – 0.05
Other milling: slot milling, t-shape milling, dovetail milling, form milling.
D: Roughing operation
A: Finishing operation
ORIENTATIVECUTTINGTABLEFOREXERCISES

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DOWN MILLING or CLIMB CUTTINGDOWN MILLING or CLIMB CUTTING
Same cutter rotation and feedSame cutter rotation and feed
UP MILLING or CONVENTIONAL MILLINGUP MILLING or CONVENTIONAL MILLING
Opposite cutter rotation and feedOpposite cutter rotation and feed
The insert starts cutting with a large chip thickness:
 It is more suitable.
 Backlash elimination is necessary. Vibration tendency ↑.
 Fc tend to pull the workpiece into the cutter.
 Not recommended when using ceramic inserts (fragile).
The insert starts cutting at zero chip thickness:
 Rubbing  Friction ↑, Fc ↑, Machine power ↑
 Temperature ↑, work-hardened surface, Ra ↓
 Fc tend to: lift the workpiece from the table, push the
cutter and workpiece away from each other.
 Tensile stresses ↑ when teeth exit, tool life ↓
Mc
Ma
MILLING: Discontinuous cutting process
Ma
Mc
MILLING DIRECTION
by Endika Gandarias
VIDEO VIDEOVIDEO

44
HIGH SPEED MACHINING (HSM)
by Endika Gandarias
HSM: Feed faster
than heat
propagation.
Traditional milling: time for
heat propagation.
In comparison with traditional milling:
Spindle speed (N) ↑, feed rate (F) ↑ and axial cutting depth (ap) ↑.
Radial cutting depth (ae) ↓ and feed per tooth (fz) ↓.
F F
VIDEO

45
CHARACTERISTICS:
More productive cutting process in small sized components.
Possible to be used with high-alloy tool steels up to 60-63 HRc (EDM process can be avoided).
Excellent surface roughness can be achieved (Ra ~ 0.2 µm).
Machining of very thin walls is also possible.
Typical applications: dies and moulds, difficult to machine materials,…
by Endika Gandarias
Trochoidal milling
(typical HSM technique)
Progressive cutting
(constant stock)
Constant peripheral
cutting speed (Vc)

46
by Endika Gandarias
DISADVANTAGES:
Higher maintenance costs: Faster wear of guide ways, ball screws and spindle bearings.
Specific process knowledge, programming equipment and interface for fast data transfer is needed.
It can be difficult to find and recruit advanced staff.
Human mistakes, hardware or software errors give big consequences. Emergency stop is practically
unnecessary.
Good work and process planning necessary.
Safety precautions are necessary:
Machines with safety enclosing (bullet proof covers).
Avoid long overhangs on tools.
Do not use “heavy” tools and adapters.
Check tools, adapters and screws regularly for fatigue cracks.
Use only tools with posted maximum spindle speed.
Do not use solid tools of HSS.

47
by Endika Gandarias
MILLING STRATEGY
 When using a ball nose end mill, tilting the cutter
10 to 15 degrees can improve tool life and chip
formation and provide a better surface finish.
VIDEO
ROLL-IN TECHNIQUE

48
by Endika Gandarias
MILLING STRATEGY

49
by Endika Gandarias
MILLING STRATEGY
THIN WALLS
 ae sould be minimized (20% Dc).
 ap should not exceed 100% Dc
 Big entry-exit radii should be programmed.
 Sharp and positive cutting edges should be used.
WEAK FIXTURE

50
CENTER-LINE OF THE CUTTER
OUTSIDE THE WORKPIECE
IN LINE WITH THE WORKPIECE
INSIDE THE WORKPIECE
hex = fz  cutter hits, no shearing
MILLING STRATEGY
by Endika Gandarias
ae > 70% x Dc ae < 25% x Dc
hex < fz  high productivity
CVD coating inserts recommended
(better thermal protection)
hex < fz  F ↑ to mantain productivity
PVD coating inserts recommended
(sharper cutting edge)
Carbide handles the compressive stresses at the impact of entering well.
VIDEOVIDEOVIDEO

51
OUTSIDE THE WORKPIECE
IN LINE WITH THE WORKPIECE
INSIDE THE WORKPIECE
Chip thickness is at its maximum
At exit, chip bends and generates tensile forces on the carbide increasing fracture possibilities.
VIDEO
by Endika Gandarias
MILLING STRATEGY

52
• Best for shoulder face milling
& where 90° form is required.
• Low axial forces  Thin walls,
weak fixtured components,…
• Best for face milling & plunge milling.
• Excellent for ramping operations.
• Lower radial forces  Lower vibration.
• Chip thickness ↓  feed ↑ to keep productivity.
• Best for face milling & profiling operations.
• Excellent ramping capabilities.
• Strongest cutting edge with multiple
indexes.
• The chip load and entering angle
vary with the depth of cut.
: Cutting edge angle affects the cutting force direction and the chip thickness.ENTERING ANGLE (Kr)
VIDEO VIDEO VIDEO VIDEO
_ +
Chip thickness _+ Length of contact
by Endika Gandarias
90º 45º 10º VIDEO

53
 The pitch is the distance between the effective cutting edges.
 Different pitches:
 Differential pitch: A very effective way to minimize vibration tendencies.
PITCH (u)
_ +
Productivity
Machine power consumption
by Endika Gandarias
Vibration
VIDEO

54
TOOL HOLDER ALIGNMENT RECOMMENDATIONS:
Finishing
by Endika Gandarias
< 0.006 mm
Roughing
Tool overhang (A) and total length
(B) should be minimized.
Attention to the max. allowable torque.
It depends on the tool holder type and tool diameter.

55
Surface finish, i.e. Surface Roughness, is mainly determined by the distance between the
contiguous toolpaths, tool radius and surface slope.
How to calculate the axial (ap) and radial (ae) cutting depths to
achieve a certain theoretical roughness?
In this type of milling; Ra ≈ Rmax/4
ae = Radial depth of cut
ap = Axial depth of cut
Rmax = Rz = Max. roughness
Rhta = Tool radius
α = Surface slope
Rmax ↓
ae ↓
ap ↓
Rhta ↑
SURFACE ROUGHNESS:
by Endika Gandarias

56
In ball end mills, cutting happens at points with different diameters. Thus, as the whole tool rotates at
the same spindle speed, the cutting speed varies along the ball end.
Effective radius in ascending toolpaths Effective radius in descending toolpaths
EFFECTIVE TOOL RADIUS
by Endika Gandarias

57
CUTTING PARAMETERS: DRILLING
by Endika Gandarias
vc
N Vc · 1000 Vc: Cutting speed (m/min)
N = N: Spindle speed (rpm)
π · Dc Dc: Tool diameter (mm)
N
VIDEOVIDEO

58
2. Feed
IN
DRILLING
FEED PER
REVOLUTION
(fn)
→
3. Cutting depth (ap)
F [mm/min]
FEED RATE
or
FEED PER MINUTE F = fn·N
by Endika Gandarias
ap
VIDEO

59
DRILL ALIGNMENT RECOMMENDATIONS:
by Endika Gandarias
0.02 mm 0.02 mm
Rotary drill Stationary drill
B
A
Feed force
Better B than A tool position
(lower torque).
Tool alignment method.
VIDEOVIDEO

60
fn ⅓ fn ⅓fn ⅓fn
A B C D
ENTRY AT NON-PLANAR SURFACES:
by Endika Gandarias
MACHINE
WORKPIECE
MATERIAL
Vc
(m/min)
fn
(mm/rev)
DRILLING
MACHINE
STEEL
HIGH SPEED STEEL
(HSS)
Spot drilling 18 0.04 – 0.1
Drilling 18 0.04 – 0.1
Counterboring 9
Countersinking 9
ALUMINIUM
HIGH SPEED STEEL
(HSS)
Spot drilling 30 – 40 0.04 – 0.1
Drilling 30 – 40 0.04 – 0.1
Counterboring 15 – 20
Countersinking 15 – 20
ORIENTATIVECUTTINGTABLE
FOREXERCISES

61
Excellent Acceptable
Start chip
Chip jamming
The start chip from entry into the workpiece is always
long and does not create any problems.
Chip jamming can cause radial movement of the drill
and affect hole quality, drill life and reliability, or
drill/insert breakages.
A hole affected by chip jamming.A hole with good chip evacuation.
CHIP CONTROL
The chip formation is acceptable when chips can be
evacuated from the drill without disturbance.
The best way to identify this is to listen during drilling:
 A consistent sound = chip evacuation is good.
 An interrupted sound indicates chip jamming.
by Endika Gandarias
VIDEO

62
PECK DRILLING
by Endika Gandarias
 Peck drilling may be necessary if chip evacuation is difficult due to a deep hole or the
use of external lubricant.
VIDEO

63
CUTTING PARAMETERS
VARIABLE UNIT DESCRIPTION
HOW TO
CALCULATE?
TURNING MILLING DRILLING
Vc m/min Cutting speed TABLES
N rpm or rev/min Spindle speed N=(Vc*1000)/(π*Ø)
fz mm/tooth*rev Feed per tooth TABLES
fn mm/rev
Feed per
revolution
TABLES
fn = fz * z
F mm/min
Feed rate or
feed per minute
F = fn * N
Ap mm
Axial cutting
depth
TABLES
Tool radius
Ae mm
Radial cutting
depth
TABLES
Parameter introduced into the machine.
Parameter NOT introduced into the machine.
by Endika Gandarias
SUMMARY TABLE

64
CUTTING FLUIDS
CUTTING FLUIDS
by Endika Gandarias

65
Cutting fluid is any liquid or gas that is applied to the chip or cutting tool to improve cutting performance.
Cutting fluids serve 4 principle functions:
1. To remove heat in cutting (=COOLING): The energy used in the cutting process is almost
exclusively transformed into heat that goes to the workpiece, tool and chip. The effective cooling
action depends on the method of application, type of fluid, fluid flow rate and pressure.
2. To lubricate the chip-tool interface (=LUBRICATION): It reduces friction forces and
temperatures.
3. To wash away chips (=CHIP REMOVAL): This is only applicable to small and discontinuous
chips.
4. To avoid part oxidation (=ANTI-CORROSION): The environment humidity in combination with
the high temperatures (500-900ºC) obtained during machining may cause part oxidation. Thus,
the cutting fluid must contain anti-corrosion additives.
Use of cutting fluids contributes to:
 Diminish tool wear (longer tool life).
 Produce workpieces of accurate sizes (reduce thermal expansion).
 Achieve proper surface quality of the workpiece.
 Support chip removal.
 Reduce thermal stress on machine tool.
CUTTING FLUIDS
by Endika Gandarias

66
CUTTING FLUIDS
- METHODS OF APPLICATION
LUBRICATIO
N TYPE
CONTENT
USED
VOLUME
CHARACTERISTICS
Wet machining
(using coolant)
Manual application
10 to 100
l/min
Used for manual tapping. Cutting fluids are used as
lubricants.
Flooding supply
Lubricating system of machine tools need to be cleaned
from time to time to eliminate microorganisms.
Coolant-fed tooling
or internal cooling
Some tools (typically drills) are provided with axial holes
so that cutting fluid can be pumped directly to the
cutting edge. Coolant pressures up to 80 bars.
Coolant-fed tool
holders
Special tool holders required for milling, turning or
drilling operations. Coolant pressures up to 30 bars.
Reduced
lubrication
Minimum quantity
llubrication (MQL)
50 ml/h up
to 1-2 l/h
Cutting fluid is deposited as drops or air-oil mix. Valid
for not very demanding machining operations.
It can be external or internal.
Without
lubrication
Dry machining without
It shows economic and environmental benefits. Under
research.
Novel cooling methods are under research: high pressure cooling (> 70bar), criogenic cooling (N2, CO2),...
by Endika Gandarias
VIDEO
VIDEO

67
CUTTING FLUIDS
Manual application Flooding supply Coolant-fed tooling Coolant-fed tool holder
by Endika Gandarias
Titanium alloys
Nickel
Stainless steel
Hard steel ( 0.4 to 0.7 % C )
Copper
Cast-iron
Steel (More carbon more difficult)
Aluminum
Brass
Bronze
Zinc alloy
-
Machining
difficulty
+
Broaching
Shaping
Gear machining
Drilling
Reaming
Sawing
Milling
Turning
-
Machining
difficulty
+

68
CUTTING FLUIDS
by Endika Gandarias
 Cutting oils are based on mineral or fatty oil mixtures. Commonly used for heavy cutting operations.
 Soluble oils is the most common (95% of the time), cheap and effective form of cutting fluid. Oil droplets
suspended in water in a typical ratio water to oil 30:1. Emulsifying agents are also added to promote stability
of emulsion, as well as anticorrosive additives.
 Chemical fluids (synthetic) consists of chemical diluted in water. They may have harmful effects to the skin.
- TYPES OF CUTTING FLUID
Lubrication
Refrigeration
Cutting oils
Soluble oils
Chemical fluids
Water
Dry machining
Low speed applications
(broaching, threading,…)
↓
High friction
↓
Maximum lubrication
High speed applications
(turning, milling,…)
↓
Low friction
↓
Maximum refrigeration

69
SELECTION OF
CUTTING CONDITIONS
SELECTION OF CUTTING CONDITIONS
by Endika Gandarias

70
Productivity is a combination of factors that really make a difference, such as:
• Increased cutting conditions = more parts per hour
• Predictable tool life = machining security
• Fewer tool changes = less down time
• Fewer rejects = higher quality – more valuable end product
• Product availability = less inventory
• Technical training of employees = better understanding and less scrap
by Endika Gandarias
Important to identify the most relevant factors that influence the FINAL COST:
≈ 31%
≈ 27%
≈ 22%
≈ 3%
≈ 17%

71
Important to identify the most relevant factors that influence MACHINE-TOOL UTILIZATION TIME:
by Endika Gandarias

72
Machining efficiency suggests that good quality parts are produced at reasonable cost and at high
production rate.
Most relevant cutting parameters that affect machining costs and productivity are:
1. Depth of cut
2. Feed
3. Cutting speed
It is predetermined by workpiece geometry and final part shape.
 In Roughing operations  As large as possible (max. 6-10 mm).
It depends on machine tool, cutting tool strength and other factors.
 In Finishing operations  A single pass to achieve the final dimensions.
Finishing pass in a turning operationRoughing passes in a turning operation
1. Depth of Cut (ap, ae)
by Endika Gandarias

73
 In Roughing operations  As large as possible (max. 0,5mm/rev).
It depends on cutting forces and setup rigidity.
 In Finishing operations  Small to ensure good surface finish (~ 0,05-0,15 mm/rev).
Cutting at high cutting speed involves...
 Reduction of tool life  Increase of production costs
as more cutting tools are needed.
 Increase of productivity  less time consumption.
Hence, optimal cutting speed range has to be calculated for:
 Cutting speed for minimum cost per unit (Vmin).
 Cutting speed for maximum production rate (Vmax).
2. Feed (F, fn, fz)
by Endika Gandarias

74
Production cost
Fixed costs
Economic
Vc
Tooling cost
Cutting speed Vc
Costperpart
Parts per hour
Vc for
max. productivity
High efficiency
range
Machinery costs
by Endika Gandarias

75
- HOW TO CALCULATE THOSE VALUES?
Several limitations need to be considered:
1. MACHINE
2. TOOL
3. GEOMETRY
4. MATERIAL
1. MACHINE: The machinery usually exists in the workshop, and it may be a limiting factor.
Anyway, either an existing or a new machine is used, attention should be paid to
the following machine features:
 General characteristics: number of axes, machine configuration type, general
dimensions and weight,…
 Axes: traversing range, power, accuracy, max. workpiece weight, max.
acceleration and feed.
 Workholder system: Forces, vibrations,…
 Spindle head: power, speed range, run-out, stiffness, clamping system,
automation possibilities, internal cooling.
 Toolholder system: Run-out, torque,…
 Tool changer: chip to chip time, max. number of tools, tool length and diameter,…
 Cooling unit system: internal or external, MQL, HPC
 CNC controller: capabilities
 …
by Endika Gandarias

76
2. TOOL: Tool wear will occur.
There are five main wear mechanisms which dominate in metal cutting:
1. Abrasion.
2. Diffusion.
3. Oxidation (corrosion).
4. Fatigue (thermal).
5. Adhesion.
These wear mechanisms combine to attack the
cutting edge in various ways depending upon
the tool material, cutting geometry, workpiece
material and cutting data.
Flank wear is the most common type of wear
(abrasion) and the preferred wear type, as it
offers predictable and stable tool life.
by Endika Gandarias
VIDEO

77
2. TOOL
by Endika Gandarias
In the case of pasty
materials, layers / new
edges are formed.
Adhesive
SiC inclusions of Fe
foundry materials may
create cutting edge wear.
Abrasive
Chemical reaction
between tool carbides
and the machining part
create wear.
Chemical
Temperature variations
create cracks in the
cutting edge.
Thermal
Mechanical efforts on the
cutting edge create tool
failures.
Mechanic
CauseWear descriptionSymbolLoad type
FA
FA = Filo de
aportación

78
1. Flank wear
2. Crater wear
3. Plastic deformation
4. Notch wear
5. Thermal cracks
6. Mechanical fatigue cracks
7. Chipping on edge
8. Tool breakage
9. Built-up edge (BUE)
TOOL WEAR TYPES
 Inappropriate cutting conditions
 Inappropriate tool features
 Material properties
 Too low or high cutting
temperature
 …
by Endika Gandarias

79
by Endika Gandarias
VIDEO

80
Vc : Cutting speed [m/min]
fn : Feed per revolution [mm/rev]
ap : Cutting depth [mm]
T : Tool life [min]
a, b, n, C: Constants
by Endika Gandarias
VIDEO

81
Vc
fn
ap
Workpiece
material hardness
Tool
material
R: Roughing
M: Medium machining
F: Finishing
by Endika Gandarias
INSERT GRADE

82
WORKPIECE MATERIAL
INSERT GRADES
by Endika Gandarias

83
 Select geometry and grade
depending on the type of the
workpiece material and type of
application.
by Endika Gandarias

84
CUTTING DATA ON DISPENSERS
by Endika Gandarias
TURNING INSERTS

85
by Endika Gandarias

86
When increasing the cutting speed (vc), feed rate (fn) should be
decreased and vice versa.
Cutting speed and feed data compensation for turning
by Endika Gandarias

87
GLOSSARY
GLOSSARY
by Endika Gandarias

88
GLOSSARY
by Endika Gandarias
ENGLISH SPANISH BASQUE
Alignment Alineación Alineazio
Alloy Aleación Aleazio
Aluminium casting Fundición de aluminio Aluminio burdinurtua
Axial cutting depth Profundidad de pasada axial Sakontze sakonera
Backlash Desajuste Desdoitze
Ball nose end mill Fresa de punta esférica / punta de bola Boladun fresa
Bend Doblar Tolestu
Beveling Biselado Alakaketa
Brass Latón Letoia
Brazed Soldado Soldatua
Breakdown Averiar Matxuratu
Broaching Brochado Brotxaketa
Bronze Bronce Brontzea
Built-up edge Filo de aportación Aportazio ertza
Carbide Metal duro Metal gogorra
Carbon steel Acero al carbono Karbono altzairua
Cast-iron Fundición Burdinurtu
CBN (Cubic Boron Nitride) Nitruro de Boro Cúbico Boro nitruro kubikoa
Cheap breaker Rompevirutas Txirbil hauslea
Chip Viruta Txirbil
Chip Viruta Txirbil
Chipping Astillado Zati
Chisel edge Filo central Erdiko sorbatz
Clamp Abrazar Lotu
Clearance face Cara de incidencia Eraso aurpegia
Climb cutting Concordancia Konkordantzia
Coarse Basto Baldar
Coat Recubrimiento Estaldura

89
GLOSSARY
by Endika Gandarias
Contiguous Contiguo Alboko
Conventional milling Contraposición Kontrajartze
Coolant Lubricante Lubrifikatzaile
Corner radius end mill Fresa tórica Fresa torikoa
Crush Machacar Birrindu
Cutting edge Arista de corte Ebaketa ertz / Sorbatz
Cutting speed Velocidad de corte Ebaketa abiadura
Cutting tool Herramienta de corte Ebaketa erraminta
Dampened tool Herramienta antivibratoria Bibrazioen aurkako erraminta
Die Molde Molde
Diminish Disminuir Gutxitu
Dispenser Dispensador Kaxa
Dovetail Cola de milano Mirubuztan
Down milling Concordancia Konkordantzia
Drilling Taladrado Zulaketa
Drop Gota Tanta
Edge rounding Redondeo de arista Ertz biribiltze
EDM Electroerosión Elektro-higadura
Enclosing Cerramiento Itxitura
End mill Fresa plana Fresa laua
Engagement Empañe Lausotua
Fatty Graso Oliotsu
Feed per revolution Avance por vuelta Aitzinamendua birako
Feed per tooth Avance por diente Aitzinamendua hortzeko
Feed rate Avance por minuto Aitzinamendua minutuko
Finish Acabado Akabera
Flank Flanco / Lateral Albo
Flooding Inundación Gainezkatze

90
GLOSSARY
by Endika Gandarias
Friction Fricción Marruskadura
Gauge Calibrar Kalibratu
Gear Engrane Engranai
Grinding Rectificado Artezketa
Hard metal Metal duro Metal gogorra
Hardening Endurecimiento Gogortze
Hardness Dureza Gogortasuna
Harmful Dañino Kaltegarri
Heat Calor Bero
Height Altura Altuera
High Speed Machining Mecanizado a alta velocidad Abiadura azkarreko mekanizazioa
High Speed Steel (HSS) Acero rápido Altzairu lasterra
Hit Golpear Kolpe
Insert Plaquita intercambiable Plakatxo trukagarria
Jamming Atasco Trabatze
Labelling Etiquetado Etiketa jarri
Load Carga Karga
Major Mayor Nagusi
Margin Faja guia Faxa gidaria
Marking Marcado Markaketa
Milling Fresado Fresaketa
Minor Menor Txiki
Nose radius Radio de punta Muturreko erradioa
Notching Entallado Hozkaketa
Oven Horno Labe
Overhang Voladizo Hegalkin
Overhead Gastos generales Gastu orokorrak
Packaging Empaquetado Paketeak egin

91
GLOSSARY
by Endika Gandarias
Pecking Picada Ziztada
Pin Punzón Puntzoi
Pitch Paso Neurri
Plunge Penetración Barneratze
Powder Polvo Hauts
Power Potencia Potentzia
Pressing Prensado Prentsaketa
Profiling Perfilado Profilaketa
Radial cutting depth Profundidad de pasada radial / ancho de pasada Iraganaldi zabalera
Radii Radios Erradioak
Rake Desprendimiento Jaulkitze
Reaming Escariado Otxabuketa
Reject Rechazo Errefus
Relief face Cara de desahogo Lasaitasun aurpegia
Revolution Vuelta Bira
Roughing Desbaste Arbastaketa
Rubbing Bruñido Txartaketa
Sawing Serrado Zerraketa
Scrap Residuo Hondakin
Seat Asiento Eserleku
Shank Mango Kirten
Shape Forma Forma / Itxura
Shaping Limado Karrakaketa
Sharp Afilado Zorrotz
Shearing Cizallamiento Ebakidura / Zizailadura
Shell end mill Fresa hueca Kofadun fresa
Shift Relevo Txanda / Errelebu
Shim Calza Altxagarri

92
GLOSSARY
by Endika Gandarias
Shoulder milling Escuadrado Eskuairaketa
Side Lateral / Secundario Albo/Bigarren
Sintering Sinterizado Sinterizazio
Skin Piel Azal
Slope Pendiente Malda
Solid tool Herramienta enteriza Pieza bakarreko erraminta
Spindle Cabezal Buru
Spindle speed Velocidad de giro Biraketa abiadura
Spray drying Secado por pulverización Lainoztatze bidezko lehorketa
Staff Personal Langilego
Stiffness Rigidez Zurruntasun
Strength Resistencia Erresistentzia
Stress Fatiga / Estrés Estres
Substrate Sustrato Substratu
Surface roughness Rugosidad superficial Gainazal zimurtasuna
Tapping Roscado con macho Ardatzarekin egindako hariztaketa
Thickness Espesor Lodiera
Tilting Inclinación Inklinazio
Tip Punta Punta
Toolholder Portaherramientas Erraminta etxea
Torque Par Momentu
Toughness Tenacidad Zailtasun
Tray Bandeja Erretilu
Trochoidal Trocoidal Trokoidal
Turning Torneado Torneaketa
Unleaded Sin plomo Berunik gabeko
Up milling Contraposición Kontrajartze
Wash away Limpiar Garbitu

93
GLOSSARY
by Endika Gandarias
Weak Debil Ahul
Wear Desgaste Higadura
Web Alma Arima
Wedge Cuña Kuña / Falka
Weight Peso Pisua
Wet Humedo Busti
Workpiece Pieza Pieza
Workshop Taller Tailer

Cutting conditions

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