Model 16: Stepdwell motion of a strip for punching and
extrusion
Kinematic scheme:
Dimensions:

Dimensions
[m] 
a 
0.0240 
b 
0.0480 
d 
0.0635 
k 
1.016823 rad 
r 
0.4074 
e 
0.0306 
f 
0.0125 
g 
0.045 
h 
0.063 
m 
0.374 
n 
0.063 
u 
0.138 
v 
0.329 
p 
0.198 
q 
0.008 
a_{2} 
0.007 
a_{3} 
0.018 
c_{2} 
0.158 
c_{3} 
0.160 
a_{0} 
0.1 rad 
b_{0} 
0.5 rad 
Explanation:
The fourbar linkage performs a symmetrical coupler
curve with equal curve radius r at the symmetry points K^{1} and
During dwell the punching of the metal strip can take
place. A disk is punched out and in the same motion cycle it is deformed by the
second punch until a cuplike product. Both punches are withdrawn sufficiently
when the transport of the metal strip starts, see the picture with the transfer
functions.
Literature: VDIRichtlinie 2728I. Loesung von Bewegungsaufgaben mit
symmetrischen Koppelkurven – Uebertragungsaufgaben.
Remarks:
The motion analysis has been performed with the
program Runmec. The values of angle k and
radius r have been precalculated acc. (lit) for given (measured) values of a, b
and d. The values of m, n and f are calculated also based on them. All other
values are as measured from the model.
The start positions of both cranks are such that their
phase angle differs from the one appearing in the model. The toothed belt at
the backside of the model, connecting both cranks, is mounted such that the
phase angle is apparently not correct.
In the real machine one of the pulleys has a permanent
brake to guarantee the required decelleration of the strip.