Page 39 - Metalorming Magazine January/February 2023

Currently, metal formers rely primarily on servomechanical presses to increase production rates. However, in certain applications servo presses
with a Servo Press
also help influence formability.
BY DAVID DIAZ-INFANTE
Although servomechanical metal forming presses provide a vari- ety of servo-motion profiles, those most-often applied to improve material flow are soft contact, pulsat- ing, dwelling and restriking (Fig. 1). Depending on the workpiece material and forming process, the effectiveness of each motion profile may vary. These motion profiles started to gain popu- larity as materials with lower forma- bility and higher strength entered the market. Examples include advanced high-strength steels (AHSS) and certain aluminum alloys such as the 6XXX series.
To investigate how servo-motion profiles can help when forming these challenging materials, researchers con- ducted a set of drawing experiments using a 400-metric-ton servo press (Table 1). The experiments were con- ducted with a 100-mm square punch (Fig. 2), with a 900-kN-capacity load
David Diaz-Infante is a servo press sci- entist with Nidec Press & Automation; www.nidecpa.com.
Fig. 1—Common servo-motion profiles.
a)
STROKE
c) TIME
b)
STROKE
d) TIME
STROKE
STROKE
SOFT CONTACT
TIME
TIME
PULSATING
DWELL
COINING / RESTRIKING
Material
Al 6005/1.0 mm
980xG3/1.4 mm
644
1011
17.6
24.3
DP980/1.4 mm
786
1014
6.3
13.2
Press tonnage capacity
Stroke length
Bolster area
Shut height
Max. shift speed
4000 kN
350 mm
3050 mm by 1400 mm
450 mm to 700 mm
Yield Strength [MPa]
Tensile Strength [MPa]
Uniform Elongation [%]
Total Elongation [%]
130
237
19.7
N/A
53 rpm
Table 1—Press Characteristics
36 MetalForming/January/February 2023
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Table 2—Mechanical properties of the materials