Safe and flexible printing

July 2016

The Czech machine manufacturer SOMA Engineering relies on safety technology from Rexroth for its central impression flexo printing machines.

In many industries, there is an increasing focus on changeover times. This is also the case within the printing industry, where they are becoming more and more important due to falling print runs and thus more frequent job changes. Printing machine manufacturers are able to better support their customers if they transfer process and safety functions into the machine software and reduce engineering work with pre-programmed technology functions and modular safety technology. With its latest generation of machines, SOMA Engineering, a Czech manufacturer of central impression flexo printing machines, is therefore banking on Rexroth's IndraMotion automation solution. It includes a motion-logic system with a large number of pre-programmed technology functions that are typically used in the printing industry, such as tension control, register control and intelligent servo drive technology. To ensure safe changeover, the Czech company's design engineers have combined a central safety controller with decentralized safety functions that are integrated in the drives. Since Rexroth's decentralized safety functions monitor safety without going through the control system, they can respond quickly in the event of a fault. This is particularly important for SOMA Engineering, as the company uses highly dynamic direct-drive technology for the central cylinder and other functions.

Access forbidden!

The working space of the machine is closed during printing. The SafeLogic compact safety controller monitors the door contacts with the Safe Door Locking (SDL) function preventing unauthorized entry into the printing area. When the machine is at a standstill, appropriate safety functions protect the user while the machine is set up, cleaned, changed over or while a fault is remedied.

SOMA is backing sleeve technology for fast changeover. Operating personnel can change the sleeves in ongoing operation at no risk to themselves even though the drive is still in control. Using Rexroth's solution, you do not have to deenergize the machine to do this: The corresponding drives are grouped in a safety zone, for which the safety functions are activated with a software command. SOMA Engineering uses the SOS Safe Operating Stop safety function for sleeve changes. This monitors whether the motor keeps exactly to its position.

Engineering work reduced

The uniform IndraWorks programming environment and the combination of the safety controller with the certified safety functions that are integrated in the IndraDrive drives considerably reduce the amount of engineering time and effort involved. The modular control solution fits into a wide variety of different automation solutions by growing at the same rate as the peripheral signals. The Safety Wizard guides users through the process of setting safe drive parameters, guaranteeing that all the necessary safety functions have been configured and parameterized and generating an acceptance report.

Simple configuration

Users configure and program the SafeLogic compact and commission it with the SafeLogic Designer. The program results from linking the configured inputs and outputs graphically with elements from the comprehensive module library. In simulation mode, you can quickly determine whether it is running error-free. Another special feature: Rexroth's safety controllers work on a non-reacting basis. This means that machine manufacturers can adapt their machine program and the processes to customer specifications without having to modify the safety controller and verify it again.

SOMA Engineering

SOMA Engineering has been manufacturing high-quality processing and printing machines since the beginning of the nineties. SOMA's central impression flexo printing machines, which are offered in three series, print flexible packaging materials, such as plastic foils and paper, in different thicknesses. Eight to ten printing units are arranged in a circle around the central cylinder in a diameter of more than three meters.