More throughput, productivity and flexibility in the production of complex and multi-variant components, at the same time ergonomically improved workstations - and all this in less space.
Aebi Schmidt, manufacturer of vehicles for cleaning, clearing and maintaining traffic and green spaces, seems to have succeeded in squaring the circle: The Company relies on the Centrick rotating and tilting manipulator for the assembly of voluminous cabs and hoppers.
The assembly of dirt strainers and cabs is an essential step in the production of sweepers such as the Swingo 200+ made by Aebi Schmidt in St. Blasien near Freiburg. “It is important that the assembly process is flexible and simple and that both the productivity of the department and the ergonomics of the workstations are optimally designed,” says Philipp Jacoby.
As coordinator for production planning and staff deployment, the 28-year-old is responsible for the Swingo compact sweepers with 2 m3 hoppers.
Since the use of the Centrick rotating and tilting manipulator for the Swingo 200+, there has been no need for time-consuming training of employees on the production line. Previously, they first had to acquire the necessary know-how to master the processes of the complex product in assembly.
The production times for the approximately 450 compact sweepers of the Swingo series with 2 m3 hoppers per year vary considerably, making personnel planning more difficult: If a standard model is ready in eighty hours, a version with extensive additional equipment can take up almost twice as much time. “The large number of possible variants resulted in very different capacity utilisation during assembly. Together with the workflows being synchronized, the staff’s scheduling became a challenge and slowed production down,” explains Jacoby.
“Another characteristic feature of the production of the series is the strong fluctuation in incoming orders over the year from customers throughout Europe,” says Philipp Jacoby.
The work was not always comfortable for the 35 employees: For the installation of dirt strainers on the sweepers, they had to climb into the interior of the voluminous hopper lying on the floor and mount the components there, partly lying on their backs. This required a great deal of routine, skill, experience and mobility.
Features that were equally necessary to mount the vehicle steering system with its hydraulic supply, the brake booster and the pedals on the bottom of the sweeper cab. To do this, the employee first crawled under the cab, which weighed around 200 kg. There he fixed the cab to a frame. After he had got up again, he moved both into a vertical position with the aid of a lifting device. Only then could he start assembly.
Together with Gebhard Lehner, work planner at Aebi Schmidt, Jacoby developed a concept to improve the situation. “We are always looking for ideas to simplify our work and activities,” says Lehner, describing his motivation as a work planner. He found a decisive inspiration during a trade fair: “At the Motek I saw at a stand how an engine block and a lawn mower were moved with the Centrick rotating and tilting manipulator. I knew right away: that's what we need. Because there is nothing comparable on the market.”
The ROEMEHLD Centrick is an electrically driven rotating and tilting manipulator for the mobile assembly of heavy components up to 2,000 kg. Workpieces can be tilted by 90°, endlessly as well as continuously rotated and optionally lifted. All axes are driven electrically and backlash-free. Brakes hold any position safely. A special arrangement of the articulated arms and the patented tilting kinematics ensure that the centre of gravity of the workpiece does not shift and that it always retains the optimum assembly position.
This feature provides the Centrick with an advantage over conventional rotating and tilting fixtures. In most cases, these have only one arm and swivel over a significantly larger travel; that’s why the working height varies more – to the disadvantage of back-friendly working.
The little swivel radius of the Centrick also ensures very high stability. Also, less working space is required than with conventional tilting processes. This allows integration into existing working areas, even in limited spaces.
“Tilting kinematics in a limited space is very important for us”, explains Lehner. In 2014, Aebi Schmidt purchased the first Centrick for the assembly of the hoppers. “We were immediately convinced and ordered the next model for cab assembly.”
The use of the Centrick ensures that today the hopper, weighing more than 100 kg and measuring 90 x 210 x 130 cm (H x L x W), can be worked on almost fatigue-free. It is delivered to the assembly workstation on a transport rack, and then the employee attaches it to the rotating and tilting manipulator. He already uses the pick-up device with which the component is later attached to the sweeper. Via the cable-bound two-hand operation, he then rotates the workpiece by 90 degrees at the push of a button. Now he can mount the dirt strainers on the side and in the middle of the hopper comfortably and back-friendly in standing position.
Work on the cab has also become easier. The operator pushes it into the Centrick together with its transport rack. One push of a button is all it takes for the manipulator to safely move the 200 kg part to the desired position. The fitter can then easily fix all components to the bottom in a standing position. The cab is then transported on its transport rack to the next station for the further work steps.
After the assembly workstations had been significantly improved ergonomically, the team of the Swingo line started the following year to convert the production into a “breathing production” with quickly variable output. As a result, the assembly department is now in a position to react quickly to a changing order situation: With just a few changes, weekly production can be more than doubled in real time and - if necessary - shut down again.
An important prerequisite for the new work organisation was that additional employees – including temporary workers hired from outside at short notice – could be quickly integrated into production. The two Centricks help to ensure that assembly work on the cab and hopper is carried out with high productivity after only a short time, even by less experienced personnel.
During the restructuring, the two manipulators could be easily relocated and space-savingly integrated into the new processes. For users who want to use the compact high-tech element for mobile applications, there are lockable rollers as an option for easy movement.
The Centrick is currently available in two basic versions for loads up to 500 kg and up to 2,000 kg. The smaller variant A500 uses a scissors principle with a 310 mm stroke, while the A2000 with a column construction lifts heavier weights by up to 1,000 mm. The tilting and rotating axes are fitted as standard, and the lifting function is available as an option. Other optional extras include a media feed-through for the rotary axis and operating elements for welding applications and safety devices. The manipulators are driven by low-noise 230 V AC electric motors. Due to the efficient kinematics, power consumption is usually less than 700 W.
The Aebi Schmidt Group is a leading global provider of intelligent product systems and services for the cleaning and clearing of critical traffic areas as well as for the maintenance of green areas in demanding terrain. The extensive range includes our vehicles, innovative attachments and superstructures for individual vehicle upgrades as well as an innovative range of services for customer-specific solutions.
In the financial year 2018, the company generated sales of 413 million euros and employed around 2,000 people worldwide in ten competence centres and other local sales organisations. The brand structure has been simplified in March 2019 and consists of the brands Aebi, Schmidt, Nido, Meyer, Swenson and MB. Aebi Schmidt Holding AG is domiciled in Frauenfeld, Switzerland, with a further location in Zurich.
Römheld GmbH Friedrichshütte
Product range - Clamping Technology
Tel. : +49 (0) 6405 - 89456
Aebi Schmidt uses a Centrick A500 for tilting with scissor lift for the assembly of the cabs, and a version for tilting and rotating and without lifting is used for the hoppers. “The standard cable remote control is sufficient for our requirements. Thus, we can do without an enclosure and save space,” explains Lehner.
Besides this push-button operation, there is also a variant with controlled height, rotation and tilt adjustment via a programmable teach-in control for repeatable, process-controlled series production. Also available is a radio remote control for towing with driverless transport systems and for use on conveyor systems.
For Aebi Schmidt, the two manipulators save a lot of time while at the same time increasing handling safety and ergonomics, praises production planner Philipp Jacoby: “We are completely satisfied. The Centricks are very reliable, maintenance-free, the ROEMHELD service is fast when something needs to be done, and the spare parts supply is excellent.”