# Mechanical press - energy of flywheel

1. Jan 5, 2012

### abelli

Goodmorning,
I know that the mechanical power press constructors give:
1) the diagram of permitted work depending on used number
of slide single stroke per minute;
2) the diagram of eccentric loads on the slide (ellipsis graph).

But I don't know how they can do these ones.
For question 1. I presume that the iter calculation is:
- energy for forming: E0=rated Force x rated distance to BDC
- energy for deformation press: E1=F^2/2xRigidity press
- energy losses: E2= ...? (x% of E0 ?)
Total energy: Et=E0+E1+E2 this is the energy in continous operation
(permitted work on automatic strokes).

Now, for the press flywheel, assuming a slowdown of 20% during
continous stroking, the energy stored in the flywheel is:
Ev=Et/(1-0.8^2)
So the inertial moment of flywheel is: J=Ev/iω^2

Now the questions are:
a) first of all: how can I calculate the drive motor power (kW) ?
b) above all: how can I calculate permitted work on single strokes ??
(I've read somewhere the energy in single strokes is about twice-2- of continous operation: why? I don't think 2 is a magic number...)

2) In the end how can I drawing diagram of eccentric loads ?

I really thank everyone help me.