A safety light curtain installation for a Cape Town-based non-metallic mineral product manufacturer resulted in operator efficiency improvement of almost 20%. The manufacturer, IWT Abrasives, approached ElectroMechanica (EM) in 2019 for a system that would improve safety around its hydraulic press, and simultaneously enhance press productivity. This installation has continued to prove itself, two years later.
IWT specialises in the weaving and impregnation of glass fibre rovings used in the reinforcement of cutting and grinding wheels. Its hydraulic press shapes flexible material into the form of grinding disks. To operate the press, the operator uses two hand lever valves. This mechanism ensures operator safety, but it slows throughput. A further concern for IWT was the high energy consumption of the hydraulic press due to its constantly operating hydraulic pump, which also heated the oil, reducing its lifespan.
“IWT wanted a solution that would address these concerns while also improving operation productivity”, explains William Cameron, EM Production Manager. “We proposed our ReeR light curtains to replace the two hand lever safety mechanisms, which automatically and swiftly halts any press movement if the light beam is interrupted”.
IWT had previously installed similar light curtains from EM on their Chiesa cutting machines. After doing some research on the ReeR brand, IWT agreed that the positive market feedback, affordability and recognised quality made this the ideal solution for their requirements.
EM supplied all required products for the scope of work, which was undertaken by IWT engineers. The project consisted of removing the existing hand-operated hydraulic valves, simplifying the hydraulic circuit to a single solenoid-controlled valve and installing sensors to measure stroke movement and the force applied by the press. A new control cabinet to house the new PLC-based control system was supplied, as was a Human Machine Interface (HMI) to enable operator feedback.
The combination of sensor feedback and light curtain protection enabled the press to perform its action autonomously and to automatically reset. This allows operators to prepare the next product for pressing safely and efficiently, contributing to increased production. “The extra time gained has added a lot of value for IWT,” says Cameron.
The use of a PLC into the solution created smarter press control, resulting in the aforementioned improvement in operator efficiency and reduced waste, as well as the energy savings. In terms of production, the biggest improvement over the last two years has been quality consistency and subsequent waste reduction, since the PLC limits the force and movement of the press. The improved control provides the hydraulic pump the ability to switch off automatically when the press has been idle for a specified period, increasing system longevity.
“Safety in manufacturing enterprises is often overlooked due to the expected loss in productivity and complexity of adoption. However, safety solutions can be implemented in a phased approach, with minimal disruption and can lead to significant productivity returns,” concludes Cameron.