Overview of the various cutting processes

Transcription

Cutting Processes
Simulation Techniques in Manufacturing Technology
Lecture 7
Laboratory for Machine Tools and Production Engineering
Chair of Manufacturing Technology
Prof. Dr.-Ing. Dr.-Ing. E.h. Dr. h.c. Dr. h.c. F. Klocke
© WZL/Fraunhofer IPT
Aim of the lecture
This lecture is supposed to…
 …give a general understanding of selected techniques of
machining with geometrically defined cutting edge.
 …teach the characteristics and range of application of the
principles of manufacturing technologies.
 …illustrate the characterizations of the different
manufacturing processes
Seite 2
Outline
1
Introduction
2
Cutting processes with rotary motion
3
Cutting processes with parallel translation
4
Hard machining
5
Modeling of Machining
Seite 3
Classification of manufacturing processes according to DIN 8580
Manufacturing processes
Primary
Shaping
Forming
Separation
Joining
Coating
Change
material
characteristics
Severing
Cutting with
geometrically
defined cutting
edges
Cutting with
geometrically
undefined cutting
edges
Removal
operations
Disassembling
Cleaning
Turning
Drilling,
Reaming
Milling
Sawing
Processes with rotational primary movement
Planing,
Shaping
Broaching
Filing,
Rasping
Brushlike
tools
Scraping,
chiseling
Processes with translational primary movement
Seite 4
Classification of processes with rotational primary movement
 Turning
– Workpiece
rotation
– Tool translation
Primary movement
Subsidiary
movement
 Milling
– Tool rotation
– Workpiece
translation
Primary movement
Sub. movement
 Drilling
– Tool rotation
– Workpiece
translation
Primary movement
Sub. movement
 Sawing
– Tool rotation
– Workpiece
translation
Primary movement
Sub. movement
Seite 5
Classification of processes with translational primary movement
 Broaching
– multi teeth tool
– tool geometry implies
feed
– high cutting ability
– high surface quality
– high accuracy
– high tool costs
– inflexible
 Planing
 Shaping
– cutting motion by work
– cutting motion by tool
piece
– workpiece feed
– tool feed
– stepwise, linear cutting
– stepwise, linear cutting
motion
motion
– successive feed movement
– successive feed movement
– machining of large, planar
– machining of large, planar
areas
areas
f
Tool
Workpiece
vA= vc
vr
Seite 6
Outline
1
Introduction
2
2.1 Turning
2.2 Milling
2.3 Drilling
3
4
Hard machining
5
Seite 7
Outline
1
Introduction
2
2.1 Turning
2.2 Milling
2.3 Drilling
3
4
Hard machining
5
Seite 8
Turning of steel
 vc = 200 m/min
f
= 0.6 mm
 ap = 5.0 mm
 Ck 45
Source: ISCAR
Seite 9
High speed filming of turning process
 r = 102°
f
= 0.35 mm
 ap = 1.5 mm
 Ck 45
Seite 10
Turning processes (DIN 8589-1)
Turning DIN 8589-1
Face
Turning
workpiece
Cylindrical
Turning
workpiece
Helical
Turning
workpiece
Hob
Turning
workpiece
Profile
Turning
workpiece
Form
Turning
workpiece
Getriebe
tool
tool
tool
tool
tool
tool
Source: Iscar, Seco, Sandvik Coromant, Lingenhöle
Seite 11
Face turning (Parting off)
Source: ISCAR
Seite 12
Rough turning
Source: Widia
Seite 13
Finish turning
Source: Widia
Seite 14
Terms at the cutting edge
tool shank
cutting direction
rake face Ag
feed direction
minor cutting edge S‘
major cutting edge S
major flank face Aa
minor flank face Aa‘
corner radius
Seite 15
Tool reference systems
Tool in hand system
Tool in use system
Pr = Tool reference plane

ve
Pp
Pfe
Pf = Assumed Working plane

vc
Pf

ve
PP = Tool back plane

vc
Ppe

vf

vf
Pre
Pr
nach DIN 6581
Seite 16
Definition of the tool cutting edge angle r
Tool orthogonal plane Po
Tool reference plane Pr
Tool cutting edge plane Ps
Seite 17
Definition of tool cutting edge angle r
Workpiece
rε
f
Direction of feed
r
ap
Working plane Pf
Tool
Tool cutting edge plane PS
Seite 18
Definition of the inclination angle ls
Working plane Pf
Tool cutting
edge plane Ps
Tool reference
plane Pr
Seite 19
Definition of the inclination angle for longitudinal cylindrical turning
Working plane Pf
n
Cutting insert
Workpiece
Tool holder
ls
Tool reference
plane Pr
+
Cutting direction
Feed direction
Tool cutting edge plane PS
ap
Shaft
Seite 20
Definition of the tool orthogonal rake angle g
Tool cutting edge Ps
Seite 21
Process kinematics at the idealised wedge
 The wedge geometry is
defined by the clearance
angle aO, the wedge angle bO
and the tool orthogonal rake
angle gO.
Cutting
direction
h
 The wedge penetrates the
material and causes elastic
and plastic deformations.
Chip
Workpiece
go
bo
Rake face Ag
 Due to the given geometry
the deformed material is
forming a chip which flows
across the rake face
Tool
Cutting surface
ao
Flank face Aa
ao + bo + go = 90
Seite 22
Penetration of tool and workpiece: Cross-sectional area
Workpiece
Direction of rotation

vf
h = f  sin r
kr b
 Depth of cut
ap
 Feed
f
 Width of
b
 Undeformed
h
chip thickness
h
 Cross section of
undeformed chip
A
r
undeformed chip
kr

vf
 Tool cutting edge angle
ap
Tool
A
A = ap  f = b  h
f
b=
ap
sin  r
Seite 23
Tool variants in longitudinal cylindrical turning
right hand
side cutting
left hand
side cutting
neutral
Feed direction
Source: ISCAR
Seite 24
Facing (DIN 8589-1: ON 3.2.1.1)
Cross face turning
workpiece
tool
Cross parting off
Longitudinal face turning
workpiece
workpiece
tool
tool
Source: Sandvik Coromant
Seite 25
Facing (DIN 8589-1: ON 3.2.1.1): cross / longitudinal face turning
Seite 26
Facing (DIN 8589-1: ON 3.2.1.1): cross parting off
Seite 27
Cylindrical turning (DIN 8589-1: ON 3.2.1.2)
Longitudinalcylindrical turning
Centreless rough turning
Cross-cylindrical
turning
n
Workpiece
vc
n
f
f
n
n
Tool
f
f
Workpiece
Tool
Source: Iscar, Ceratizit
Seite 28
Helical turning (DIN 8589-1: ON 3.2.1.3)
Thread turning
Thread chasing
Gewindedrehen
(außen)
outer
n
n
f
Gewindedrehen (innen)
Inner
f
Source: ISCAR Sandvik
Seite 29
Profile turning (DIN 8589-1: ON 3.2.1.5)
Trepanning
Grooving
workpiece
Cross-profile turning
workpiece
tool
tool
workpiece
tool
Source:
Seite 30
Contour turning (DIN 8589-1: ON 3.2.1.6)
NC contour turning
Copy turning
workpiece
Kinematic
contour turning
workpiece
workpiece
tool
tool
NC
tool
gear
reference formed part
Seite 31
Internal turning
Skimming
Undercut
workpiece
Cut in
workpiece
workpiece
tool
tool
tool
n
n
f
n
f
f
Source: Lach-Diamant, Iscar, Boehlerit
Seite 32
Internal turning tools
Source: Sandvik
Seite 33
Outline
1
Introduction
2
2.1 Turning
2.2 Milling
2.3 Drilling
3
4
Hard machining
5
Seite 34
Face milling (DIN 8589-3: ON 3.2.3.1)
Seite 35
Face milling (DIN 8589-3: ON 3.2.3.1)
Seite 36
Milling processes (DIN 8589-3)
Milling
Face
milling
tool
workpiece
Circular
milling
tool
workpiece
Helical
milling
tool
workpiece
Hob
milling
tool
workpiece
Profile
milling
Form
milling
tool
tool
workpiece
workpiece
Source: Sandvik Coromant, Walter, Fette, Milltech, Seco, Gleason
Seite 37
Slab milling: face and peripheral milling
 Face milling
– Workpiece surface is created with the
face plane
 Peripheral milling
– Workpiece surface is created with the
peripheral plane
vf
vf
Ps
n
fz
n
Tool
r
Tool

vc
ap
ae
Workpiece
Workpiece
fz
Seite 38
Up and down milling
Down milling
n
Up milling
fz
fz
Chip
n
Fc
vc
ae
vc
Fc
vf
Down
milling
Up
milling
Ploughing
▼
▲
Surface quality
▲
▼
Chatter
▼
▲
Clamping forces
▼
▲
vf
Up- and down milling
n
vf
Up milling part
Down milling part
Seite 39
Tool-in-hand system: Face milling
vf
trace of Ps
tool
trace of Po
wA
n
wc
wE
r
ap
νf
n
trace of Pf
workpiece
fz
fz
Pr
ae
trace of Pp
trace of the
entrance plane
Seite 40
Tool-in-hand system: Peripheral milling
vf
fz
trace of Pr
vc
tool
ae
workpiece
w E = 0
wc = w A - w E
Pf  Po
trace of Ps  Pp
Seite 41
Contact conditions and cutting edge geometry in face milling
fz
ae2
n
vc
C
ae
C
s
ae1
vf
-eA n
A
+eE

φ=0
entry plane
tangential plane
A
cutting C-C
fz
ap
tool cutting edge
U
T
gp
A
B
B
b
plane B-B
n
Sb
K
S Sa V Va
b=
ap
h
sin
i = arccos
contact types
tool


a ei
D2
 
= f  sin  sin
z
r
(fz << D)
Seite 42
Precision milling operations
fz1
fz1
ap1
ap
ap
fz
fz
fz
fz
Finish milling
no. of teeth: 10 to 60
ap = 0.3 bis 1 mm
fz = 0.3 bis 0.5 mm
ap
ap
fz2
ap2
fz2
ap1
ap2
Wide finish milling
Finish milling with planing knives
and wide finishing cutting edge
no. of teeth: 1 to 6
no. of planing knives:
20 to 30
ap = 0.05 to 0.2 mm no. of wide finishing cutting edges: 1 to 2
fz = 0.5 bis 6 mm
finishing
ap1 = 0.5 to 2 mm
cutting edges fz1 = 0.1 to 0.3 mm
wide finishing ap2 = 0.03 to 0.05 mm
cutting edges fz2 = 2 to 5 mm
Seite 43
Indexable end mills
Source: Coromant Sandvik, Seco
Seite 44
Inserted tooth milling cutter
Source: Coromant Sandvik, Seco-Tools
Seite 45
Example of use: Blisk (Blade Integrated Disk)
Seite 46
Circular milling (DIN 8589-3: ON 3.2.3.2)
workpiece
workpiece
nw
ap
nw
tool
nF
nF
vf
vf
additional axial cutting edges
tool
radial cutting edges
nF
Mill
nW
workpiece
chipping space
Source: Walter
Seite 47
Helical milling (DIN 8589-3: ON 3.2.3.3)
A
B
C
D
E
F
Seite 48
Hob milling
fa
vc
fw
 vc: Cutting speed
 fa: Axial feed
rotation
of hub
radial feed
axial feed
rotation of
workpiece
 fw: Hob feed
Source: WZL,Gleason
Seite 49
Different hob types
Solid steel hob
Inserted blade hob
Indexable cutter
 High rotational speeds
 High material removal rates
 No regrinding
 Short milling times
 Roughing and Finishing
 Relatively low accuracy
 Short setting distance
 Easy regrinding
 Roughing
 Large gear diameters
 Large gear diameters
and modules
and modules
Source: Fette, Saazor, Saacke
Seite 50
Profile milling (DIN 8589-3: ON 3.2.3.5)
Profile milling cutter
Gang milling cutter
tool
workpiece
workpiece
workpiece
Source: Sandvik Coromant, Ingersoll, Alesa, Seco
Seite 51
Form milling (DIN 8589-3: ON 3.2.3.6)
Form profile milling
tool
worpiece
Source: Milltech, Dalscheid
Seite 52
Outline
1
Introduction
2
2.1 Turning
2.2 Milling
2.3 Drilling
3
4
Hard machining
5
Seite 53
Example of gun drilling
Source: Widia
Seite 54
Example of gun drilling
Seite 55
Drilling processes DIN 8589-2
Drilling, Countersinking, Reaming
Spot facing
Centre drilling
tool
tool
workpiece
workpiece
Tapping
Profile drilling
Form drilling
tool
tool
tool
workpiece
workpiece
workpiece
Seite 56
Criteria for drilling
n
 Material separation and reaming at the major
cutting edge
friction
 Plastic deformation at the chisel edge
f
friction
 Cutting speed drops down to zero in the centre
of the drill
 Chips are difficult to remove
 Unfavourable heat distribution at the interface
 Increased wear at the sharp-edged corner
 Reaming between leading lands and drilling wall
workpiece
plastic
deformation
material
separation
Source:
Seite 57
Geometry of the cutting part of a twist drill (DIN 8589-2)
drill diameter d
cutting part
plunge (lettering point)
flat tang
tapered shaft
plunge length
point length
cutting length
cone length
flute length
total length
Seite 58
Geometry at the cutting edge of a twist drill
major
Hauptschneide
cutting edge
a
Querschneide
chisel edge
flank
Freifläface
che
Construction dimensions DIN 6539
Type:
N
Diameter:
d = 1 mm
Drill-point angle: s = 118°
d
Major clearance angle:
Twist angle:
Cutting material:
Grain size:
a = 10°
d = 35°
HW-K20
DK = 0.5 – 0.7 µm
Seite 59
Cutting conditions dependent on drill diameter
0
1
6
7
afe
gfe
vc
8
9
chisel edge
5
main cutting edge
4
drill radius r in mm
2
10
40°
30°
20°
10°
0°
-10°
-20°
-30°
-40°
-50°
-60°
Rake angle g and candlearance angle a
20
10
cutting speed vc in m/min
0
Seite 60
Fundamental kinematics: Centre drilling
gf
b
g
a
f
cutting edge 1
cutting edge 2
axe
h
f/2
cutting direction
h
effective direction
feed direction
Seite 61
Fundamental kinematics: Centre drilling
vf
n
minor cutting edge
n
trace of Po
trace of Pr
tool
major cutting edge
web
thickness
vc
trace of Ps
trace of Pp
r =
er
Pp
trace of
chisel edge
workpiece
s
ap =
2
h
fz
Pr
trace of Pf
s
ap
1
D
2
Pr
b
Seite 62
Twist drill for various materials
Type
Point angle
s/°
Twist angle
d/°
Material
N
118
18 to 30
e.g. steel
H
118
10 to 15
e.g. grey cast iron
W
130
35 to 45
e.g. Aluminum
σ
σ
σ
Source: DIN 1414
Seite 63
Specific geometries of twist drills
Form A
Form A
Form B
Form C
Form D
Form E
Form
Form
AB
Form
Form
A AForm
Form
Form
ABForm
CForm
Form
AB BForm
Form
Form
BCForm
Form
DForm
BC CForm
Form
Form
C Form
D Form
EForm
C D DForm
Form
D Form
E Form
Form
D E EForm E Form E
KegelmantelAusgespitzte
KegelmantelKegelmantelKegelmantelAusgespitzte
KegelmantelAusgespitzte
Ausgespitzte
Ausgespitzte
Ausgespitzte
Ausgespitzte
Ausgespitzte
Kreuzanschliff
Ausgespitzte
Ausgespitzte
Ausgespitzte
Kreuzanschliff
Ausgespitzte
Ausgespitzte
Kreuzanschliff
Kreuzanschliff
Kreuzanschliff
Ausgespitzte
Spitzenwinkel
Kreuzanschliff
Ausgespitzte
Ausgespitzte
Ausgespitzte
Spitzenwinkel
Ausgespitzte
Spitzenwinkel
Spitzenwinkel
Spitzenwinkel
Spitzenwinkel
cone
shapedKegelmantelPointed
pointed
cutting
edge
cross-wise
pointed
transverse
point
angle 180°
anschliff
anschliff
Querschneide
anschliff
anschliff
anschliff
Querschneide
anschliff
Querschneide
Querschneide
Querschneide
Querschneide
Querschneide
Querschneide
Querschneide
Querschneide
Querschneide
Querschneide
Querschneide
Querschneide
180° mit
Querschneide
Querschneide
Querschneide
180° mit
Querschneide
180°
180°
mit
mit
180° mit180° mit
drill
(basic polish
transverse
withmit
corrected
major
polishmit Zentrumsspitze
cutting
edge
with Zentrumsspitze
with
centre tip
(Grundanschliff
(Grundanschliff
(Grundanschliff
(Grundanschliff
(Grundanschliff
(Grundanschliff
mit korrigierter
korrigierter
mit
mit
korrigierter
korrigierter
mit korrigierter
mit mit
facettierten
korrigierter
facettierten
mit
mit
facettierten
facettierten
mitZentrumsspitze
facettierten
mitZentrumsspitze
facettierten
Zentrumsspitze
Zentrumsspitze
cutting
edge
cuttingHauptschneide
edge
facetted
cutting
für form
Form A-D)
A-D)
für
Form
Form
für
A-D)
A-D)
Formfür
A-D)
Form A-D)
Hauptschneide
Hauptschneide
Hauptschneide
Hauptschneide
Schneidenecken
Hauptschneide
Schneidenecken
Schneidenecken
Schneidenecken
Schneidenecken
Schneidenecken
for
A-D) für Formfür
edge corners
Seite 64
Drilling processes I (DIN 8589-2)
Drilling:
Cutting with circular primary motion. The axis of rotation of the tool and of
the produced internal area are identical. The direction of the feed has the
direction of this axis of rotation.
Centre drilling
primary
motion
Tapping
tool
tool
feed
motion
Gun drilling
Profile drilling
primary
motion
primary
motion
primary
motion
feed
motion
feed
motion
feed
motion
tool
tool
workpiece
workpiece
workpiece
tool
workpiece
Seite 65
Gun drilling
drill bushing
cemented
HM - Kopf
carbide
mit
Schaft
shaft
head
with indexable
eingeschliffenen
inserts
Fü hrungsleisten
lubrication
outlet
cutting edge
crimp
Source: Sandvik
Seite 66
Deep hole drilling
Single lip drilling
BTA-Method
Ejector-Method
Diameter range
Diameter range
Diameter range
0,8 to 40 mm
6 to 300 mm
18 to 250 mm
Source: Sandvik
Seite 67
Example of use: Micro deep hole drilling
Source: TITEX
Seite 68
Drilling processes II (DIN 8589-2)
Sinking:
Drilling for producing planes which are orthogonal to the axis of rotation or
rotationally symmetric cone and form planes.
Reaming: Bore up with a low undeformed chip thickness for producing better qualities
of the surface.
Countersinking
Reaming
primary
motion
primary
motion
feed
motion
feed
motion
tool
tool
tool
workpiece
workpiece
workpiece
primary
motion
feed
motion
Cylinder sinking
Seite 69
Round reaming
Boring with small uncut chip thickness with a reamer in order to produce a
high precision cylindrical inner surface with excellent surface quality
n
n
vf
Tool
vf
Workpiece
Reaming
Reiben
Reiben
Form reaming
Seite 70
Solid-carbide reamer
Source: Iscar, Rübig, Gühring
Seite 71
Construction principle of a reamer with guide rail
Mounting Mounting screw Cutting insert
plate
Adjusting screw
Source: MAPAL
Seite 72
Reamer with two PCD-cutting edges and PCD-guide rail
Source: MAPAL
EN-GJL-250, vc = 120 m/min, vf = 675 mm/min
Seite 73
Construction types of multibladed reamers
Source: SECO, DIHART, MAPAL
Seite 74
Outline
1
Introduction
2
3
3.1 Shaping/ Planing
3.2 Broaching
3.3 Sawing
4
Hard machining
5
Seite 75
Outline
1
Introduction
2
3
3.2 Broaching
3.3 Sawing
4
Hard machining
5
Seite 76
Definitions and kinematics
Planing/
shaping:
Cutting with repeated parallel translation as primary motion and successive
feed motion which is orientated orthogonal to the primary motion.
The kinematics of planing and shaping are identical. When the primary motion
comes from the workpiece the process is called planing, when the primary
motion comes from the tool the process is called shaping.
Planing
Shaping
primary motion
at the tool
primary
motion at the
workpiece
Seite 77
Planing processes (DIN 8589-4)
Finish planing
primary
motion
Contour planing
feed motion
Profile planing
feed
motion
tool
Circular planing
feed
motion
tool
tool
tool
workpiece
feed
motion
workpiece
primary
motion
workpiece
primary
motion
workpiece
primary
motion
Seite 78
Outline
1
Introduction
2
3
3.2 Broaching
3.3 Sawing
4
Hard machining
5
Seite 79
Broaching processes I
Broaching:
Cutting with a tool with more than one flute. The flutes are orientated one after
another with the stepping of the undeformed chip thickness. The feed motion is
substituted by the stepping. The last flutes of the tool produces the desired
profile of the workpiece. After one run, the workpiece is ready and the surface
finished.
Plane broaching
primary
motion
External broaching
feed
motion
workpiece
primary
motion
feed motion
tool
Internal broaching
feed
motion
tool
tool
workpiece
primary
motion
workpiece
source: DIN 8589-5
Seite 80
Broaching processes II
Profile broaching
feed
motion
primary
motion
Helical broaching
tool
tool
Cylindrical broaching
feed
motion
tool
primary
motions
primary
motions
workpiece
workpiece
initial shape of
the workpiece
workpiece
end shape of
the workpiece
workpiece
tool
source: DIN 8589-5
Seite 81
Internal broaching tools (schematic)
end piece
A
shank
way
roughing-
fz
t
finishing-
calibrating part (fz=0)
ba01
B
a01
a02
g0
ba01
detail B
width of chamber
a01 chamfer inclination
t
division
g0
fz
inclination
a02
detail A
clearance angle
rake angle
Seite 82
Broaching tools
Source: Forst
Seite 83
Example of use for internal broaching
Source: Forst
Seite 84
Used proceedings for the production of turbine discs
End milling
Drilling
Turning
Broaching
Source: MTU
Seite 85
Outline
1
Introduction
2
3
3.2 Broaching
3.3 Sawing
4
Hard machining
5
Seite 86
Sawing processes
sawing:
Cutting with circular motion or parallel translation as primary motion. The
Tools have more than one flute. The depth of cut is low and the primary
motion comes from the tool.
Hack sawing
feed
motion
Band sawing
tool
primary
motion
workpiece
feed
motion
tool
workpiece
Circular sawing
tool
primary motion
primary
motion
workpiece
feed
motion
source: DIN 8589-6
Seite 87
Nomenclature and tool geometry of the saw band
go
Width Tooth root
R
H
bo
Band saw
ao
t
Tooth point Tooth space
(chip space)
Back
of blade
Cutting
part
vc
h
ve
fz
90°
Working plane Workpiece
ae
t
Tooth pitch
R Base radius
H Tooth height
vc cutting speed
ve Effective cutting speed
fz Tooth feed
ae Intervention width
Seite 88
Outline
1
Introduction
2
3
4
Hard machining
5
Seite 89
Hard machining with geometrically defined cutting edges
Techniques
Cutting materials
 turning
 ultra fine grained carbides
 milling
 ceramics
 broaching
 PCBN
Technological specialties
 cutting process is conducted by a single or a few cutting edges
 strong relation between the condition of single cutting edges and the surface rim zone of
the workpiece, because the materials are hard and thus the tools posses a high wear risk
 risk of white layers
Seite 90
Mechanically strong steel parts need to be hardened / tempered
Hardening steel leads to mechanically strong parts
Soft
Hardening /
Tempering
Hard
Micro structure: Martensite
Hardness: 20 - 35 HRC
Hardness: 55 - 65 HRC
Stress s
Stress s
Micro structure: Ferrite
Strain e
Material volume: 100 %
Strain e
Material volume: Approx. 103 %
non-uniform strain and
distortion
=> Final cut necessary to achieve high accuracy in form and size,
small and medium parts need to be oversized by approx. 0.3 - 0.5 mm
Seite 91
Typical parts for hard machining
Cams shaft
Slipping load
(e.g. contact with bucket tappet)
Bearing rings
Rolling load
(contact with rollers)
Micro slipping
(Contact with shaft)
Gears
Rolling load
(Contact with partner gear)
Bending load
(at tooth ground)
Slipping load
(Contact with synchronising ring)
Seite 92
Hard machining, turning and grinding
 Hard machining can be realised by
defined and undefined machining principles.
 Hardened steel can only be cut defined if the
material in front of the cutting tip is heated
and softened by the process itself.
 This leads to special requirements for the
cutting material and the press design.
Seite 93
Application for Precision Hard Turning
Machining time [%]
Part:
Material:
Machining:
Precision profile roller
O 150 mm
X210CrW12
hardened (63 HRC)
Hard turning of the
profile
Machining Cost [%]
100
100
90
90
80
80
70
70
60
60
50
50
40
40
30
30
20
20
10
10
Grinding
Hard Turning
Grinding
Hard Turning
Seite 94
Outline
1
Introduction
2
3
4
Hard machining
5
Seite 95
Force calculation: Time function
Substitution of the empirical force equation proposed by Kienzle with the technical terms:
1- mi
Fi = ki1.1  b  h
diameter of the tool
(1- mi)
p  D  v f


 sin w  sin  r 
Fi  ki1.1 
sin  r  z  vc

equation proposed by
Salomon or Kienzle
ap
number of teeth
polar coordinate
source: Diss. Rehse
hmax  f z  sin  r  sin w
b=
Question: What is the angle w?
)
2b
w=
D
ap
sin  r
)
b = vc  t
Discretisation of the equation

a p p  D  v f
 2  vc  dt 

 sin
  sin  r 
dFi  ki1.1 


sin r  z vc
 D 

(1- mi )
basement for modeling
Seite 96
Force calculation: Technical terms
discretisation of the equation:
dFi  ki1.1 
p  D  v f

 2  vc  dt 

 sin


 sin r 
sin  r  z  vc
 D 

ap
(1- mi )
Solving the equation for
discrete times
discrete time function
discrete force components
dFi (dt )
force in x / N
calculated
measured
time / sec
addition of the force
components in x- and
y- direction separately
transformation of the
force components into
the x- and y- direction
The same procedure
for the other flutes!
Seite 97
Penetration calculation: Peripheral milling
data of the machine tool
data of the tool
data of the workpiece
Matrix model for the penetration calculation
feed
velocity
vector field for representation of the tool
vector field for the representation of the workpiece
thickness of cut h
width of cut b
Seite 98
Thank you for your attention!!
Seite 99
Questions
 How can one differ the manufacturing processes by their primary movement?
 Which contact conditions exist in external circular cylindrical turning?
 Why is there a necessity to have both a tool in hand and tool in use system?
 Describe the most important angles at the cutting wedge.
 Name the benefits and disadvantages of up- and down milling.
 List different process variants for drilling.
 Why is reaming used?
 Which correlation exists between the helix angle and the hardness of the workpiece
material in drilling?
 Please name the different sawing processes and their process characteristics.
 Which characteristics distinguish the different methods of planing and shaping?
 How is broaching characterized?
 Which are the most important processes to manufacture involute gear profiles?
Seite 100

Overview of the various cutting processes

Transcription

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