Collaboration of robots and workers to improve factory logistics
Klefer, with its 200 employees, manufactures elevator doors in its premises of 12 000 m2 in Kilkis, Greece. In the past 20 years it has established a firm position in the domestic and international market and has an annual turnover of EUR 90 million. Now it plans to expand its production capacity.
Thanks to expertise and highly automated machine tools, the manufacturing process could easily accommodate even larger orders, if only shop-floor logistics didn’t slow down the process. Raw materials and half-finished parts are transported by trolleys and forklifts operated by warehouse workers and machine operators.
An assembly line with conveyor belts is not an option for Klefer, as items to be moved vary from large metal plates to small wheels and screws. The L4MS experiment gave Klefer an opportunity to test how the present workflow could be partly automated by using robots in collaboration with people.
3D simulation to help design and decision making
Klefer selected one production line, the construction of landing mechanism, to represent the challenges in the production of elevator doors. CERTH, Centre for Research and Technology Hellas, started to work on a solution by creating a digital twin of the present process. This allowed simulation of future automation.
“3D simulation of the process was very useful especially in the beginning of the experiment when we started to design the system. It gave us a lot of insight without having to spend too much time on the shop floor and without installing any systems at an early stage. We got a clear idea of where the bottlenecks were and where to direct our efforts,” says Ioannis Mariolis, scientist at CERTH.
It turned out that factory workers walked some 3 km per day picking and delivering materials, and half-finished products spent approximately 15 idle minutes on each workstation while forklifts were occupied.
The plan was to replace manual trolleys by AGVs (Automated Guided Vehicles) and to enable tracking of forklift availability.
“The benefits were immediately clear through the 3D simulation. It showed we could decrease walking distances and forklift delays resulting in shorter production times,” says Vasilios Trantafilidis, General Manager of Klefer.
OPIL platform to support fast deployment
CERTH specialists developed the solution on the OPIL platform to which an AGV and a forklift were connected, and so were the workers with their tablets and smartphones.
In the new solution machine operators are able to order raw materials via OPIL, and warehouse workers are able to send them with the AGV. Operators can also send half-finished products from one workstation to another with the AGV. Further, OPIL enables an easy interaction between machine operators and forklift drivers, allowing drivers to optimize their routes and thus shorten the idle time of materials.
“OPIL was a very convenient common framework for everything, and it certainly saved our time,” Mariolis says. Installation of the logistics automation in the factory took a couple of days after preliminary work had been done with the OPIL tools.
“In another factory, we would be even faster. We would make only some small refinements regarding the map of the environment, selection of the targets and positioning of the robots,” says Giannis Kostavelis, scientist at CERTH.
Reducing time spent on walking and waiting
The benefits were readily seen during the experiment. As robots took on repetitive tasks, workers were able to focus on their primary tasks, and manufacturing processes became faster.
- Materials spent 30% less time idle on the workstation. This means that 15 minutes of idle time reduced to 10 minutes per material per workstation. In the whole production line idle time decreased from 540 minutes per day to 360 minutes per day.
- Workers walked 1.3 km less per day.
The cost of the solution is estimated to be EUR 150 000 in the tested production line.
“This experiment inspires us to reshape our manufacturing plan by integrating logistic automation in the production lines,” Trantafilidis says.
OPIL tools used in the Klefer solution by CERTH:
- Digital twin: the external 3D simulation tool Visual Components
- Task Planner
- Human Agent Node: to enable Human-Machine Interface
- Container Tracking Node
Partners in the L4MS experiment:
- Factory: Klefer SA, SME manufacturing elevator doors
- Solution provider: Centre for Research and Technology Hellas