Pit stops for the crossbar feeder
A decisive factor for the high output performance of Schuler press lines with ServoDirect Technology is the Crossbar Feeder. This automation solution developed by Schuler ensures the fast and safe transfer of parts from one forming station to the next. In order to increase its lifetime and avoid unscheduled press downtime, Schuler Service now also offers customers in China a standardized on-site maintenance concept for Crossbar Feeders.
A servo press line makes around 3.4 million strokes per year – significantly more than a conventional mechanical press line. For the Crossbar Feeders, this means they have to accelerate and brake almost 14 million times to place a part in the following die and return again – representing an enormous load for the components used.
“Planned preventive maintenance for the Crossbar Feeders is the surest way to raise availability of the whole line and thus improve overall equipment effectiveness (OEE),” says Schuler Managing Director Axel Meyer, who heads the Service division. “By making scheduled replacements of individual highly stressed components in line with their expected lifetime, the Crossbar Feeders remain virtually new for a very long time and technical innovations can also be incorporated.”
In the course of developing the maintenance concept, Schuler examined the Crossbar Feeder assembly units – lifting axis, swivel arm, hand and energy chain – and defined sensible service intervals based on expected component lifetime according to the part manufacturer and our own experience. The results are the so-called planned “pit stops” of varying scope, similar to a car’s service program.
The first small service, for example, is due after five million strokes or around one-and-a-half years of full-load operation. A specialized team from Schuler Service exchanges such elements as the toothed belts, energy chains and hoses, as well as various silencers, then performs a function test and puts the Crossbar Feeder into operation again – all at the customer’s site.
General overhaul on own test stand in Dalian
A medium service is due after a further five million strokes. During this time, the Service experts replace the customer’s Crossbar Feeder with a new or reconditioned and tested unit. At its own test stand at the Dalian facility, which has numerous parts and components in stock, Schuler overhauls various linear guides and transmissions and conducts intensive test runs – in addition to the measures of the small service.
The next small service is then due again after a further five million strokes. It takes around six years in total, or approximately 20 million strokes, before the first large service is due. Once again, Schuler Service takes the Crossbar Feeder to its test stand in Dalian to replace further components, such as pulleys and bearings – in addition to the parts replaced during the small and medium service. After this, the maintenance cycle starts again from the beginning.
“The small service of one or more Crossbar Feeders in parallel takes just 14 hours of machine downtime, and due to the scheduled exchange of complete Crossbar Feeders, the medium and large service take a mere 20 hours,” stresses Managing Director Axel Meyer. “The unscheduled standstill of a press line due to the failure of a replacement part which wasn't exchanged on time can take much longer and thus incur far higher costs for the operator than the planned implementation of our standardized maintenance concept.”