Hello, I'm Lionel Broglia with Siemens PLM Software.
The objective of this demo is to simulate hydraulic circuit of a press brake,
and optimise its energy efficiency, while maintaining the performance.
I will demonstrate how the "green" design tools functionalities
of LMS Imagine.Lab Amesim will support this energetic analysis.
So first, the press brake is a mashing tool for bending sheet and plate metal.
Let's describe shortly the hydraulic system.
The lowering speed is controlled with the brake valve CB, here.
To lift the press, the flow output from the pump
enters the smaller chamber of the hydraulic cylinder
trough the flow control valve, and the check valve.
Let's have a look now at the working cycle.
During the first step, we have a high speed descent, until we are close to the metal.
Then we have a pause, of half a second, and then we have a third phase,
with a lower speed, until we reach the press with the metal sheet.
The next phase is a folding phase, where we have the deformation of the metal,
where the force from the press to the metal is increasing.
Then we have another pause of half a second, maintaining the pressure on the sheet of metal.
And the last phase is the lifting phase.
So, the cycle is about eight seconds.
Let's have a look at the energy consumption of the electric motor that rotates the pump.
We see that to perform the cycle, we need 70 kilojoules (kJ) of energy
and we can see that we need a peak of power of 32 kilowatts (kW).
Let's have a look now where the energy is consumed into the system.
So now, using the green design tools: power, energy, activity here,
we can have access to the losses into the circuit.
So let's have a look at the major dissipations into the system.
So they are the following.
The main losses into the system are due to the mechanical efficiency of the pump.
The second losses are linked to the friction inside the hydraulic cylinder,
and the third one is due to the dissipation, inside the relieve valve, here.
We can see that we have also another important dissipation that is due to the brake valve, here.
Let's have a look now when in the cycle this energy is lost.
We can see here that the hydraulic dissipation into the relieve valve happens
when we are in the stage pause maintaining folding force.
If we zoom into this stage, we can see that the objective of this stage
is to maintain the pressure inside the cylinder.
But when the pressure reaches 225 bars, the relieve valve, RV, opens.
And in fact almost all the flow created by the pump goes trough the relieve valve,
and very few enter into the cylinder.
That is the main reason of the dissipation.
So, as an improvement, we could reduce the velocity of the pump during this phase, using an inverter.
So let's have a look now at the modified LMS Amesim model.
Here, with an electric motor machine and a speed control,
in order to reduce the speed when no displacement of the press brake is required.
If we have a look now at the results, and compare the results with the
previous simulation, we can see that from a performance point of view,
we have exactly the same behavior.
But looking at the energy consumption, we see that we were able
to reduce the energy consumption from 71 kJ to 61 kJ,
so almost 12 percent of energy consumption reduction.
And this energy consumption reduction happens exactly during the folding phase.
If we look in details, we see that we reduced the speed of the pump from 1500 rpm to 150 rpm,
that is the minimum speed required in order to maintain the pressure into the hydraulic cylinder.
Let's have a look now at the new losses of the system,
in order to check which are now the most important losses.
So again looking at the major one.
We still have as main dissipation, the friction inside the hydraulic cylinder.
The second is the mechanical efficiency of the pump,
and the third one is due to the brake valve.
So, another improvement could be to store the kinematic energy of the press,
when lowering inside an accumulator.
So this is the new model that we have developped, using the accumulator to store the energy
during the descent of the press and reusing this energy during the lifting of the press.
Let's have a look again at the results.
Here we compare the three simulations. The blue one is a displacement of the standard machine.
The green one with an inverter, and the red one with an inverter and an accumulator.
Again, from an performance point of view, we have exactly the same duration of the cycle,
but from an energetic point of view, again, we were able
to reduce with an accumulator by 5 kJ the energy consumption of the machine.
But all in all, we have reduced 22 percent the energy consumption of the machine
by modifying either the control of the hydraulic pump and adding an accumulator,
we were able to reduce by more than 20 percent the energy consumption.
As a conclusion, I have demonstrated that the functionalities inside LMS Amesim are available
to pinpoint the energetic losses into the system, to propose modification and check the improvement by simulation.
Thank you for watching, if you have more questions please visit our website.