**4. Conclusion**

172 Metal Forming – Process, Tools, Design

*3.5.3. Performance analysis* 

*a* ω

*b* ω

*c* ω

To assure the continousness of ram displacement, velocity and acceleration, NURBS of *k* = 3

ω

=0.8, and 6

ω , *<sup>b</sup>* ω , and *<sup>c</sup>* ω

ω

ω , *<sup>b</sup>* ω

ω

 and *<sup>c</sup>* ω

ω

shock, vibration and noise. This is consistent with the comparison of goal functions. The

To validate the new concept, a servo press prototype with 200 ton punching force has been developed in our lab. As shown in Figure 15, the machine is more than 5 meters high and 2 meters wide. Experimental studies are being performed on this prototype including

(a) displacement (b) velocity (c) acceleration

dynamic performance, dynamic control and stamping process planning.

= min ( | | <sup>0</sup>

is the nearest to the desired trajectory

is the least that helps to decrease

respectively.

ω=0.7.

*<sup>n</sup> <sup>v</sup> i i* <sup>Σ</sup> <sup>=</sup> ).

respectively. From

is more flat for drawing

is applied here. The constraints relating the punching speed are listed as:

To limit the velocity fluctuation, the goal function is defined as *F*( )

Hence, we can get the optimized weights 3

As discussed above, the optimized weights are

= [0.5, 1, 0.5, 0.7, 0.8, 0.7, 0.5, 1, 0.8, 0.5, 0.8, 0.7, 0.9].

= [0.5, 1, 0.9, 0.4, 0.5, 0.2, 0.5, 1, 0.8, 0.5, 0.8, 0.7, 0.9]

Figure 14 displays the ram motion curves under weights *<sup>a</sup>*

period, and the fluctuation of the ram acceleration of *<sup>a</sup>*

goal function values are 20441, 20457 and 20606 under *<sup>a</sup>*

**Figure 14.** The optimized ram motion

*3.5.4. The prototype development* 

for drawing and releaseing period, the ram velocity curve of *<sup>a</sup>*

= [0.5, 1, 0.3, 0.5, 0.1, 1, 0.5, 1, 0.8, 0.5, 0.8, 0.7, 0.9]

the figures, it can be seen that the ram motion of *<sup>a</sup>*

Here another two weights are set for comparison as:

1. drawing period: -300mm/s < 1 *v t*( ) < -100mm/s, and 0.99s < t <2.25s, and 2. releasing period: 330mm/s < ( ) <sup>2</sup>*v t* < 500mm/s, and 2.51s < t < 2.97s.

> ω =0.5, 4 ω =0.7, 5 ω

> > In this chapter, a new concept of programmable metal forming press of redundant parallel actuation is presented to make it possible to develop a larger servo mechanical press using servomotors available. Based on the above discussions, following conclusions can be drawn:

