5. 1.3
- Most Commonly Used Extrusion Processes
Forward rod extrusion
Forward cup extrusion
Backward cup extrusion
P=punch, C=container, W=workpiece, E=ejector
6. - Process Combinations
Combined forward rod and
backward cup extrusion
1.4
Combined forward and
backward cup extrusion
P=punch, C=container, W=workpiece, E=ejector
7. - Forming Sequence
(a) Sheared Billet
(a)
(b)
(c) Forward extrusion
(c)
(d)
(e) Upsetting of flange and
coining of shoulder
(e)
(b) Forward rod and
(d) Backward cup
backward cup extrusion extrusion
Several kinds of operations may be combined
to obtain the desired geometry
15. Trapped Die Extrusion Criteria
D
C
L
For Most Common Extrusion Si zes
? Max. Reduction in Area,
Punch
%R .A . = 70 ~ 75%
D2 ? d 2
% R .A . =
¡Á 100
2
D
? Die Insert Inner Diameter, (inch)
D = Billet Dia.
Billet
(4)
+ 0.010
l
+ 0.012
? Die Land, (inch)
l=1
32
~1
16
d
Container
16. Open Die Extrusion Criteria
For Most Common Extrusion Si zes
? Max. Reduction in Area,
D
C
L
Punch
%R .A . = 30 ~ 35%
D2 ? d 2
% R .A . =
¡Á 100
2
D
Billet
D
2
? Die Insert Inner Diameter, (inch)
D = Billet Dia.
+ 0.002
l
+ 0.004
? Die Land, (inch)
l=1
32
~1
16
d
Container
18. Backward Cup Extrusion Criteria
C
L
? Max & Min Reduction in Area:
20 ~ 25% ¡Ü %R .A . ¡Ü 70 ~ 75%
% R .A . =
2
dP
D
2
Punch
¡Á 100
w
? Max Depth of Extruded Hole:
h = 2 ~ 3¡Á dP
? Min Bottom Thickness
h
Billet
t
of Extruded Cup:
t = 1 ~ 1.5 ¡Á w
Ejector
Container
20. Punch Nose Design
C
L
Based on Punch Diameter,d P
? Flat Diameter,
d f = d P ? [ 2 R + ( 0.2 ~ 0.3 )d P ]
? Included Face Angle,
2¦Á = 160 o ~ 170 o
? Punch Land,
l = 0.3 ~ 0.7 ¡Á d P
¦Â
R
df
l
? Punch Radius,
R = 0.05 ~ 0.1 ¡Á d P
? Relief Angle,
2¦Á
¦Â = 4o ~ 5o
dp
Punch design recommended by ICFG [6]
23. Investigation of broken tool
Observation
inspection
Assumpption of the tool failure
mechanism
Knowledge
experience
Suggestion and execution of
countermeasures
FE, simulation
No
Satisfactory
Tool life
Yes
Finish (Standardization)
<Yamanaka, 2002>
24. Factor of mold life time
design
material
surface
Hole location
Sudden
Change of shape
Different
material
impurity
Shape of
carbide
Machihing
velocity
heat surface
treatment
machining
Surface
roughness
Steel selection
accuracy
Machihing
pressure
Mold problems
Cutting
condition
Grinding
condition
tempering
condition
quenching
condition
Surface treatment
condition
Arc machining
condition
Surface treatment
selection
Life
time
setting
Lubricant
selection
Surface
roughness
Lubricant
supply
shape
hardness
processin
g
machine
apparatus
of mold
lubricatio
n
machined
material
Usage problems
<N. Nihira. 2009>
37. Zoomed on punch face
(Local metal flow)
Case A
Angle, 2¦Á = 160 o
Case B
Angle, 2¦Á = 170 o
- Included face angle of 160 o gives better
material flow around punch nose region
59. ?? , ?? ??
Factor of hi accuracy of forging products
mold
material
material
??
??
Deformation
capability
plasticity
structure
accuracy
Forging
load
Forging
machine
Heat treatment
Surface
treatment
Heat of
process
strength
Contact
time
Surface
roughness
toughness
difference
Forging
speed
ºÝºÝߣ
motion
??
??
Fitting accuracy of
Machining
hardness
Deformation
stress
weight
Heat adhesion
Heat conduction
Temperature
Of forging
Mold
temperature
wear
Hi accuracy of
Forging products
Cycle time
????
?
Lubricant
selection
lubrication
Mass of
lubricant
??
??
method
JSTP