Klefer, with its 200 employees, manufactures elevator doors in its premises of 12 000 m2 in Kilkis, Greece. 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.

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.

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.

Partners in the L4MS experiment:
Factory: Klefer SA, SME manufacturing elevator doors
Solution provider: Centre for Research and Technology Hellas
Source: L4MS website.

DIHBU disseminates these use cases generated in projects funded through L4MS Open Calls, understanding that it is very valuable information as a reference.

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