Drive conversion to give new life to packaging machines

When equipment starts aging, out of date, and reliability degrades, many companies choose to retrofit rather than purchase new equipment. The purpose of doing so is to save money, and in more cases, to obtain a higher specification through conversion. equipment.

SIG Combibloc also chose this approach. This is a carton factory at Tyne and Wear. They used Siemens drives, motors and controls to retrofit and upgrade one of the key Flamesealer packaging machines.

"This machine has been in service since the 1970s and used the old American DC drive," explains John Duffell, head of SIG's electrical maintenance department.

"We have been repairing for some time before, but over time, the local technical support of this machine has gradually begun to decrease."

"We are aware that we must solve this problem as soon as possible."

The Flamesealer packaging machine is the core production equipment of SIG. Its role is to roll a flat blank substrate into a sleeve and then complete the plastic coating of the cardboard box through a "burning" process. Several famous carton brands produced by SIG include Ambrosia, Birds and Cadbury. The local automation expert Appcon was invited to participate in the bidding for this conversion project.

Jason Johnson, Appcon’s sales manager, described the entire process for us: “At the time, the reliability of this machine was so poor that it could not meet the reproducibility requirements of the production process.”

"A lot of parts show mechanical relaxation due to control problems. With our extensive experience in high-speed manufacturing applications, we have proposed a solution based on Siemens equipment."

“When this proposal was placed in front of SIG, they were very surprised.”
"On the one hand because it is more price-competitive than others, and more importantly, it also provides additional features compared to before the conversion. In the end the technical solution won."

Appcon won the contract. Subsequently, they used the Siemens Micromaster 440 series drives (two 15kW, one 22kW) and additional encoder input interface cards to build a new control architecture and drive system. The drive is connected to the Siemens S7-300 PLC via Profibus, while the production line characteristic parameters are set by the Siemens TP170B HMI. The machine speed in relation to the central section of the packaging machine is set in "m/min" units and this value is sent to the drive via HMI and PLC. Each slave driver can maintain a speed offset with the master by entering a specified value into the HMI. The PLC will save this value so that the slave tracks the speed change in the center section. When the task type is switched, the above characteristics can make the modification of the line speed parameter faster. At the same time, due to the addition of the storage function, when a certain task needs to be repeated, the corresponding speed parameter can be recalled again. The combination of the S7 PLC and the drive allows the motor to follow the run with a true speed offset, eliminating the traditional gear connection and maintaining a constant difference at any possible line speed.

In addition, PLC is also used to implement the system monitoring function and can provide the user with the real-time status of the fault shutdown circuit. At the same time, HMI provides fault diagnosis display function, users can obtain the driver's voltage level, overload status, fault alarm and other information at any time. The status of all I/O ports can also be easily observed through the HMI to locate faults.

"After this project, we intend to establish a long-term partnership with Siemens," explains Johnson.

"Their equipment offers extremely high quality reliability."

"If you can choose, we will use Siemens products every time."

Facts have proved that the new drive system installed on the SIG company Flamesealer packaging machine is significantly better than the original simulation system.

When the load changes, the speed of each section of the production line can be kept constant.

Finally, it is worth mentioning that, thanks to the introduction of adjustment functions and encoder feedback provided by Siemens Micromaster drives, the new system has significantly reduced the vibration of the production line.

Duffell said: "It is so quiet that I often walked over and thought - is the machine on?"

The entire conversion project of the SIG lasted two and a half days.
"Appcon is indeed quite professional," Duffell commented.
"Now employees are strongly demanding that they want to modify the remaining Flamesealer packaging machines."

Needless to say, SIG will naturally listen to employees' unanimous suggestions. At present, they are working with Appcon and Siemens to carry out the next plan and complete the refitting of the remaining Flamesealer packaging machines.

Source: "World of Drives"