BLANKING LINES WITH SERVO-PRESS

The major advantages achieved with a servo press are:

• Precise positioning of the press carriage which provides easier manoeuvring for the die change or for maintenance.
• Fast start-up.
• Increased speed.
• Fast reversal of the press movement.
• Smoothness of operation and more accurate control of the press, feed roll and swinging die.

Analysing the consumption of a supply line to a press it is evident that most of the consumption is required by the electric motors that operate during the processing of coils in automatic mode. Studying  the behaviour of the motors one by one we can see how at times some motors, such as a roller, may be consuming energy but there are other drives like the unwinder or press feeder rolls that are simultaneously returning it to the network.

Fagor designs provide an architecture for control of common motors for supply lines and presses. The aim of this architecture is to ensure that the energy that some drives return will be exploited by the drives that consume.

The SPT technology motor control has an “infeed unit” power supply common to all the main motors of the installation. This power supply generates a DC bus that feeds all the motors of the installation.

With all the motors being connected to a common DC bus, when a motor returns energy this will be exploited by another one that at that time is consuming energy.

The movement control of the FAGOR servo-press is based on two control cams designed with distinct and complementary functions and objectives for the cutting process. One cam is aimed at controlling consumption of the press by minimizing fast acceleration, and the second cam is aimed at optimising and increasing production, accelerating in the area where the cutting takes place.

To control the movement of the cyclical roller and the swinging die some electronic cams, synchronized to the position of the press, are programmed in the control. By having a centralised control for these applications, the synchronisation of axes is simple by using the programming tools in the control and avoiding the inclusion of external elements when performing the synchronisations.