Successful local technology deployment at Unilever results in adoption at facilities in Germany.
Unilever is the manufacturer of Knorrox brand spices, stock cubes and soups in South Africa. During one of its processes, a Benhil machine, used as a cube former and wrapper, accepts blended product at the input and delivers individually wrapped cubes placed in 12-pack boxes at the output of the line.
“In production for the past 15 years, the Benhil was controlled by an S5 PLC and a standard AC drive, an arrangement that had become problematic because the electronic components in the system were getting old and becoming unreliable. Extensive downtime, one hour setup and faulty timing during processing were the priority problems faced by the client,” says Shikthar Komal, Hybrid Automation.
“Over the years, technical modifications to the machine had resulted in untidy electrical panels, poor wire markings and drawings that did not reflect the latest configuration. The existing drive was also problematic as the electronic cards, replaced over the years when faulty, were no longer available. Most of the settings on the machine were mechanical and thus setup was a tedious but frequent process due to the lack of alarm messaging,” says Komal.
A mechanical rebuild and an upgrade of the PLC and control to incorporate current technology was needed urgently. The solution was developed and implemented in conjunction by a mechanical design team, electrical contractor and Hybrid Automation.
Implementation
Hybrid Automation installed an S7 313C PLC and system with all the required hardware and associated electrical equipment. A Siemens touch screen was also installed to replace the existing push button control and provide the alarm messaging necessary to show errors and machine status in real-time.
“All mechanical switches were replaced by non-contact send/receive or laser sensors. An encoder was fitted to determine cam position and output switching according to the necessary set points. This allowed redundant mechanical components to be removed; the external reset on the encoder further reduced downtime. An additional encoder was used to control weight measurement electronically via the touch screen and the gluing process integrated into the system and now under PLC control,” Komal explains.
“A new AC drive and motor were installed with the contactors, overloads and drive wired to digital inputs to provide all necessary alarming. Settings are accessed via the touch screen through the sophisticated animation and pop-ups with trending and logging capability as additional important features,” he adds.
Total output of the machine has increased by 60% and wastage reduced by 50%. In addition, the amount of rework has been minimised resulting in better quality control and the higher output efficiency means that the machine is no longer required to run a three-shift cycle.
“Hybrid Automation supplied a fully integrated solution that provides effortless operator control through machine and recipe management via the graphical user interface. When product is changed on the machine, operators no longer have to spend time preparing and adjusting the setup. Almost all settings are now electronic and can be controlled through the HMI engineered by Hybrid Automation,” says Komal.
At the local facility there are six Benhil machines, in total, three of these have been fully automated and two more are currently under upgrade. As a testament to local skills, Hybrid Automation’s South African designed control system philosophy is now due to be adopted at the client’s European facilities in Germany.
Hybrid Automation’s company profile can be viewed at: http://www.instrumentation.co.za/37127n
For more information contact Shikthar Komal, Hybrid Automation, +27 (0)83 508 7566, [email protected], www.hybridautomation.co.za
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