K. Mori, Toyohashi University of Technology Punching Drawing Forging Progressive Transfer Flexible motion Application of servo presses to sheet metal forming 1) Types of mechanical servo presses 2) Bending 3) Deep drawing 4) Hot stamping 5) Shearing and plate forging 6) Conclusions Contents Mechanical servo press AC servo motor: fast Increase in power Hydraulic servo press Hydraulic pump: slow Servo Presses servo motor Conventional time Bottom dead centre accuracy: 1m speed: 150mm/s ball screw Feedback control 80tonf, Komatsu Industry Expensive bolster slide Direct driving type press Servo press Komatsu Industry Conventional motor Cheap, best seller servo motor link Mechanical link and toggle type press Aida Engineering, Amada Servo motor high torque Motor Pulley Fly wheel Clutch and brake Motor Crank shaft Crank shaft Gear (a) Servo press (b) Conventional crank press Crank type press Easy maintenance
Transcript
K. Mori, Toyohashi University of Technology
Punching Drawing
Forging Progressive Transfer
Flexible motion
Application of servo pressesto sheet metal forming
1) Types of mechanical servo presses
2) Bending
3) Deep drawing
4) Hot stamping
5) Shearing and plate forging
6) Conclusions
Contents
Mechanical servo pressAC servo motor: fastIncrease in power
Hydraulic servo pressHydraulic pump: slow
Servo Presses
servo motor
Conventional
time
Bottom dead centre
accuracy: 1mspeed: 150mm/s
ball screw
Feedback control
80tonf, Komatsu IndustryExpensive
bolster
slide
Direct driving type press
Servo press
Komatsu Industry Conventional motorCheap, best seller
servo motor
link
Mechanical link and toggle type pressAida Engineering, Amada
Servo motor
high torque
MotorPulleyFly wheel
Clutch and brake
MotorCrank shaft
Crank shaftGear
(a) Servo press (b) Conventional crank press
Crank type pressEasy maintenance
Crank Link Soft
Pulsating 1 Pulsating 2Programming
Pendulum IterativeCoining
Amada SDE
Motions of crank servo press
1) Types of mechanical servo presses
2) Bending
3) Deep drawing
4) Hot stamping
5) Shearing and plate forging
6) Conclusions
Contents
Reduction in car weight: high strength steel sheetsTensile strength (MPa)
Application of high strength steel sheetsto automobile body panel
90°
9.6
90°
9.6
Sheet t 0
Ball screw
Servo motor
Dies
Linear scale
K. Mori et al.
High strength steel sheets:large springback
Reduction of springbackin bending by bottoming
Forming speed [mm/s]0 10 20 30 40 50
-2
0
2
4
6
8
Holding
Bottoming, 0.33% reduction in thickness
Spr
ingb
ack
angl
e[º
]
(a) Holding (b) Bottoming
Backward
(c) Re-striking
K. Mori et al.
Reduction in springback by bottomingin V-bending of 980 MPa ultra high
strength steel sheet
(a) Re-striking of bent channel
(b) With re-striking (c) Without re-striking
Chamfer
Re-strike
590MPa,1.0 mm
(b) Re-striking(a) Bending
T. Suganuma et al.
Prevention of springback and twistingby re-striking
(a) Holding at bottom dead centre (b) No holding
Prevention of springback by holdingat bottom dead centre
440 MPa sheet
Sakaguchi Seisakusho
1) Types of mechanical servo presses
2) Bending
3) Deep drawing
4) Hot stamping
5) Shearing and plate forging
6) Conclusions
Contents
Die
Punch Die cushion
Sheet
Press slide
Detaching die cushion Detaching punch
Developed Method
Fracture
Re-lubrication
Y. Tamai et al.
Improvement of deep drawabilityby detachment of tools from sheet
Fracture
(b) Detachment
(c) No detachment
590 MPa steel sheet
10
15
20
25
30
Conventionalforming
Developed method
440MPa-steel(c)
Thic
knes
s red
uctio
n ra
tio /
%
590MPa-steel(d)
Conventionalforming
10
15
20
25
30
Conventionalforming
Developed method
440MPa-steel(c)
Thic
knes
s red
uctio
n ra
tio /
%
590MPa-steel(d)
Conventionalforming
Y. Tamai et al.
No detachment Detachment No detachment
Improvement of deep drawabilityby detachment of tools from sheet
300 350 400 450 500No detachment Good Neck. NG
Detachment Good Good Good Neck. Neck.
Blank holding force /kN
Neck.: Necking, NG: Fracture
(a) Controlled ram motion
(b) Crank motion (c) Controlled motion
Fracture
Aida Engineering
Prevention of fracturein deep drawing of step cup
Backward
Prevention of fracturein deep drawing of step cup
Aida Engineering
25% reduction in speed
Crank angle [deg]
Very slow
Stro
ke /m
m
Spee
d [m
m/s
]
Prevention of seizure: decrease in temperature
H. Ando et al.
Control of forming speedin plate forging of gear drum
bottom deadcentre
DiePunchBlank
Die cushion,control Blankholder
S. Matsuno et al.
Improvement of deep drawabilityusing servo die cushion
(a) Conventional die cushion (b) Servo die cushion
Prevention of fractureby control of blankholder force
(b) High speed servo press and die cushion control
(a) Crank press
Honda Motor
Control of blankholder forcein deep drawing of automobile panel
(a) No pulsating
(b) Pulsating
Wrinkling
No wrinkling
Iiyama
Prevention of wrinklingin deep drawing by pulsating motion
Pulsating motion
(a) Conventional (b) Pulsating
Pulsating motion
Koga et al.
SUS 304Increase in limiting ironing ratio
Reduction of friction in pulsating ironing
(a) Start (b) Heating (c) Deep drawing
Heater
Blankholder
Die
T. Altan et al.
Inclusion of heating process of magnesiumalloy sheet in warm deep drawing
Warm forming of magnesium alloy laptop computer case
I. Komatsu et al.
1 shot press for controlling ram motionProgressive dies
Yutaka Giken
(c) Start (d) 1st drawing (e) Punching
(f) Burring, 2nd drawing (g) Punching, thickening
(a) Progressive and transfer dies
(b) One shot
C. Murata et al.
1 shot press for controlling ram motionMulti ram servo press
1) Types of mechanical servo presses
2) Bending
3) Deep drawing
4) Hot stamping
5) Shearing and plate forging
6) Conclusions
Contents
Heating Forming Die quenching
Hot stamping for producingultra high strength steel products
Trimming
Holding at bottomdead centre
Decrease in forming load Prevention of springback Increases in formability 1.5GPa strength
ElectrodeHolder
ダイ
ポンチ
Sheet
A
～ONOFF
Transformer
200V 60Hz
A
～ONOFF
Transformer
200V 60Hz
A
～ONOFF
Transformer
200V 60Hz
A
～ONOFF
Transformer
200V 60Hz
A
～ONOFF
Transformer
200V 60Hz
A
～ONOFF
Transformer
200V 60Hz
A
～ONOFF
Transformer
200V 60Hz
Heating: 0.96s
Forming
0.26s
Holding: 3.5s
Rapid stampingServo press
K. Mori et al.
Hot stamping having resistance heating
K. Mori et al.
Hat-shaped bending of 980MPa steelsheet using resistance heating at 980 ºC
Room temperature
550 ºC
740 ºC
980 ºC
(a) Furnace heating
(b) Resistance heating
900 ºC
K. Mori et al.
Hat-shaped bending of 980 MPa steelsheet at different heating temperatures
Resistance heating
Transfer（2s）
End
Die quenching(3.5s)
Forming
Blank holder
Blank holder
Punch
Die
Sheet
Electrode
Tailor die quenching for producing parthaving strength distribution
K. Mori et al.
100
200
300
400
500
600
0 20 40 60Distance from centre x /mm
Har
dnes
s/H
V20
As received
l = 40mm
120mmLocal heating
Whole heating x
Hardness distributionby tailor die quenching
Target
K. Mori et al.
Effect of speed on formability
(a) Cold
(c) Hot, 26mm/s(b) Hot, v = 149 mm/s
K. Mori et al.
(a) 149 mm/s (b) 26 mm/s
550
900
200
/ ºC
725
375
Temperature distribution in hot stamping
K. Mori et al.High speed stamping by servo press
1) Types of mechanical servo presses
2) Bending
3) Deep drawing
4) Hot stamping
5) Shearing and plate forging
6) Conclusions
Contents
(a) Crank motion, 101 bB (b) Variable motion, 75 dB
Reduction of noise in shearing
Aida Engineering
0.2 0.4 0.6 0.8 1.0 1.22.52.01.51.00.5
–0.5–1.0–1.5–2.0–2.5
0Time /s
Pun
ch p
ositi
on /m
m
Sheet
0
Constant
Variable
0 10 20 30 40 50 60 7065
70
75
80
85
90
95
100
Punch speed /mm·s–1
Noi
se le
vel /
dBEnvironmental
VariableConstant
K. Osakada et al.
Reduction of noise in shearing
(a) Start (b) Shearing by upper punch
(c) Shearing by lower punch (d) Punching
Upper dieUpper punch
Lower punch
Lower die
(e) Ram motion
Blank side Hole side
(f) Cross-section of sheared edge
K. Junlapen et al.
Improvement of quality of sheared edgeby push-back punching
Push-back punching
Conventional(c=20%t)
600 800 10000
10
20
30
40
50
60
Lim
iting
exp
ansi
on ra
tio
/%
Tensile strength /MPa K. Mori et al.
Relationship between limiting expansionratio and tensile strength of steel sheet
Hole expansion
Reduction in cost To forging from cutting
BarCutting
QuenchingProduct
Sheet or plate
Stamping
Quenching
Product(a) Cutting (b) Plate forging
Plate: thicker sheet
Reduction in thickness of plate Large increase in load
Plate forging
No oscillation
Oscillation
Stroke s/mm
Comp
ress
iveloa
dF/kN
0 0.5 1 1.5 2
50
100
150
200
250
300
Reduction of load in compression of plateby load oscillation
Plate
Flat die
T. Maeno et al.
1) Types of mechanical servo presses
2) Bending
3) Deep drawing
4) Hot stamping
5) Shearing and plate forging
6) Conclusions
Contents
23000 kN 4-point servo press, high speed robots, 19 spm
Fast servo press system: Honda Motor
Tandem press
1. Free motion for development of novel forming processes
2. Local slide movement for high productivity
3. Improvement of dimensional accuracy and stability due to feedback control
