Tsch?tsch H., Koth A. Metal Forming Practise: Processes - Machines - Tools
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29.1 Flexible manufacturing systems in metal forming 361
Figure 29.9a EMP 800 transfer press unit with workpiece and stock conveyor stations (Illustration
from Umformtechnik works, Erfurt, Germany)
Flexibly programmable 3-D CNC transfer
This 3D CNC transfer system (Figure 29.10) is designed as a module. The transfer movements
and the cycle times can be freely programmed within the limits of the values that apply. This
construction is designed for a universal fit with different tooling demands.
Transfer distance at the
stages 100 - 600 mm
100 - 900 mm
100 - 1200 mm
shut height 50 - 350 mm
– fully closed 500 mm
– fully opened 250 mm
lift height 0 - 200 mm
– adjustment range of
lower stroke position 0 - 200 mm
Figure 29.10 3D CNC transfer (Illustration from Umformtechnik works, Erfurt, Germany)
362 29 Future developments in metal forming presses and tool changing systems
Modular control system in an open, extendable structure
All necessary press control functions are fitted into a basic module according to the schematic
design of the press control system. To add the many functions which make the transfer press
unit fully automatic, and for a user-friendly display, each add-on module can be integrated as
needed.
The most-used PLCs are:
– SIMATIC S7 for Europe and
– Allen Bradley PLC5 for the United States
Automatic tool changing reduces non-productive times
The press and transfer system adjustment data required for each die set can be saved in the
press control system under a code number of the user’s choice. When the code number is en-
tered the separate steps of the automatic tool changing process are activated by the sequence
control system.
The destacker and strip handling unit also come with automatic devices for fast blank or coil
changes.
Integrating the controls of the destacker and the strip unit in the press control system reduces
the changeover time for the whole press unit to a minimum.
29.2 Automatic tool change systems
One way to shorten tool changing times is to use cartridge-style tool holders (Figure 29.11).
These cartridges are fixed in the working area of the press using quick-action hydraulic de-
vices. These devices are released from the control desk, the cartridge is pulled onto a change-
over table or changeover truck and replaced with a ready-to-install cartridge preheated to the
operating temperature.
The sequence of events for tool changing is as follows:
1. Tooling cartridges are locked. The ram is moved down.
2. The lock is released and the ram is moved up.
3. The tool changing truck drives up to the press. The cartridge pack is lifted and coupled on
to the changing truck.
4. The cartridge pack is pulled onto the changing truck and is ready to be taken away.
29.2 Automatic tool change systems 363
Figure 29.11 Automatic tool changing system (Illustration: Hasenclever SMS works, Düsseldorf, Ger-
many)
The four-stage cold extrusion press shown in Figure 29.12, with the tooling arranged verti-
cally, works completely automatically. Finished parts are produced in one shearing opera-
tion and four press operations, from straightening the wire to the finished screw, bolt or
other shaped part.
Depending upon the size of the workpieces, 50 to 150 workpieces per minute can be pro-
duced on this press. The following table shows the technical specifications for these presses.
As manual changeover used to take around 8 to 10 hours on this kind of press, transfer pres-
ses of this type could only be used in a cost-effective way with large-scale manufacture.
It was only when automatic tool changing systems were developed that it became possible
to substantially improve the efficiency of these capital-intensive manufacturing units.
This was the only way for these units to become flexible enough for small-scale production
to be carried out economically.
364 29 Future developments in metal forming presses and tool changing systems
Figure 29.12
Formmaster GB 25 four-column cold extrusion press.
1 wire infeed, 2 straightening device, 3 conveyor device operated in time with the press. 4 ejectors in the dies, 5 shearing s
tation, 6 central gear
equipment, 7 transfer system for workpiece transport, 8 ejector
in the punches, 9 ram, 10 main drive (Illustration from Schuler
works, Göppingen,
Germany)
29.2 Automatic tool change systems 365
Table 29.1 Technical data for the four-stage cold extrusion presses, Formmaster, GB series
Model GB 15 GB 20 GB 25 GB 30 GB 36 GB 42 GB 52
Press force kN
1000 2000 3500 4500 6300 8500 14 500
Number of ram strokes depend-
ing on pressed part 1/min
110–150 95–125 80–100 60–80 50–70 35–55 30–45
Max. wire at 600
N/mm
2
wire strength mm
15 20 25(1") 30 36 42 52
Section length max. mm
140 180 205 260 290 345 425
of the bottom die holder mm
90 110 130 150 175 215 260
of the punch holder mm
75 90 110 130 145 175 215
Ram stroke without / with
changer mm
180 220/250 250/300 300/360 360/420 420/500 520/600
Max. ejector stroke
on the bottom die side mm
120 140 170 225 250 290 320
Ejector stroke on the punch
side mm
40 45 55 70 75 85 100
Number of stages
4/5 4/5 4/5 4/5 4/5 4/5 4/5
The changeover time with the automatic tool changing system described below takes only two
minutes for a punch or die pack and 50 minutes for the whole press with five stages. The au-
tomatic tool changer for transfer presses (Figure 28.13) can change five die sets (die and
punch) weighing up to 75 kg per set. The tool changing system has five axes of movement.
Operating principle and sequence of functions:
After the tooling clamp is unlocked (Figure 29.13.1) the changer device drives from its
standby position into the tooling area. There, the open gripper jaws are positioned above the
collars of the sleeves holding the tooling so that the jaws can grip the slots. When the jaws
close (Figure 29.13.2) the tooling sleeves are pulled out of their holders. Next, the changing
device drives out of the tooling area and swings off the magazine. The double gripper arm then
pivots 180° (Figure 29.13.3) and swings the magazine in again.
The tool changing device pushes both tooling sleeves in the tooling set and in the magazine
into their holders. The jaws are then opened and the changing device drives back to its standby
position.
High-performance presses with the tooling arranged horizontally (Figure 29.14) can also be
equipped with this kind of automatic tool changing device.
366 29 Future developments in metal forming presses and tool changing systems
Figure 29.13 Automatic tool changing device for cold forming transfer presses.
1 starting position, 2 tooling packs being gripped, 3 pivoting (180°) the tooling packs and
driving back into standby position (Illustration from Schuler works, Göppingen)
Figure 29.14 Forming stations on an M2/M3 high-performance cold forming press (Illustration from
Hilgeland works, Wuppertal, Germany)
Part III: Technical tables
368 Technical tables
Table 1
k
f
1
= f (
M
p
) in N/mm
2
– soft annealed– cold forming –
k
f
1
= f (
M
p
)
Material
f
k
0
0.1
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
m
M
p
QSt 32-3(Ma 8)
250
420
496
586
646
692
730
763
792
818
–
–
Ck 10
260
450
523
607
663
706
740
770
796
819
–
–
Cq l5/Ck l5
280
520
583
654
700
733
760
783
803
821
–
–
Cq 22/Ck 22
320
530
591
658
702
734
760
782
801
818
–
–
Cq 35/Ck 35
340
630
713
807
867
913
950
982
1008
1033
–
–
Cq 45/Ck 45
390
680
764
858
918
963
1000
1031
1058
1082
–
–
Cf 53
430
770
867
975
1049
1098
1140
1176
–
–
–
–
15 CrNi 6
420
700
767
841
888
922
950
973
993
1011
–
–
16 MnCr 5
380
630
702
780
832
869
900
926
948
968
34 CrMo 4
410
730
808
893
947
998
1020
1048
1071
1092
42 CrMo 4
420
780
865
959
1019
1064
1100
1130
1156
1180
CuZn 37 (Ms 63)
280
325
438
592
706
799
880
952
1018
1078
1134
1188
CuZn 30 (Ms 70)
250
280
395
558
682
788
880
964
1040
1112
1179
1242
Ti 99.8
600
700
862
1062
1200
1309
1400
1479
1549
1612
Al 99.8
60
90
105
122
134
143
150
156
162
166
171
175
AlMgSi 1
130
165
189
217
235
249
260
270
278
285
292
298
Continued AL
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
4.0
4.5
5.0
m
M
p
Al 99.8
60
182
185
188
191
194
196
200
202
204
210
214
Al MgSi 1
130
309
314
318
323
327
331
335
338
342
–
–
369
370 Technical tables