The precision of drive technology and automation systems manufacturer SEW-EURODRIVE’s highly dynamic servo-geared units and software are responsible for assembly line and testing solutions provider Jendamark Automation’s innovative technology for “shrinking” catalytic converters, which are designed and built in South Africa for the global market.

Based in Gqeberha, in the Eastern Cape, Jendamark Automation is a specialist in advanced automated assembly systems for powertrains, catalytic converters, hydrogen technologies and other automotive components. Jendamark Automation executive innovations director Yanesh Naidoo says that 95% of the locally produced machines are exported and are in operation in parts of Europe and in India and the US. 

“The shrinking machine - or ‘shrinker’ - is a core component within our catalytic converter assembly cell. This cell is a highly automated production environment in which multiple machines, robots and laser measurement systems operate in coordination,” he says.

The process begins with the core of a catalytic converter - a ceramic “brick” or monolith, coated with precious metals such as platinum and palladium, that converts exhaust gases into less harmful emissions. This brick is wrapped in a thick spring-like insulation mat and inserted into an outer casing (or can) of stainless steel. In this process, there are many variable factors to consider, Naidoo explains.

“Because the ceramic monolith is extruded and baked, its diameter can vary slightly - by  2 mm or 3 mm in a passenger vehicle converter and up to 10 mm in a truck converter. This makes the size of every monolith slightly different,” he says.

To secure the monolith inside the casing with the right spring load, the casing itself has to be adapted. This is the key function of the shrinking machine – to reshape the stainless steel casing to the exact diameter required for each brick and mat combination. Shrinking stainless steel to tolerances of 50 µm requires enormous force and control which the shrinker achieves by closing a set of heavy tapered segments around the can.

“For a passenger vehicle converter, we use 12 segments, while for a commercial vehicle converter, which is larger, we use 16. We pull a massive steel ring back over those segments and as the ring moves the segments close in, collapsing the can evenly around the monolith.”

Driving that motion are two powerful SEW-EURODRIVE servo motor systems, each connected to precision roller screws that pull the ring from both sides. Synchronising those drives is critical.

“If one side is pulled just a few millimetres more than the other, this will damage these very expensive roller screws. This is where SEW-EURODRIVE’s technology comes into its own; the drives and controllers keep the two motors synchronised to within very fine tolerances, even at the high speeds we need to hit our 30 second cycle times,” he explains.

The speed at which Jendamark Automation’s shrinker operates is one of its critical advantages, Naidoo emphasises, and this has been achieved through its innovative tool changer. He explains flexibility is particularly important in converter production for commercial vehicles as variants change every few hours. Traditionally, each change required a lengthy manual tool change which would mean two to three hours of downtime.

“This is why we developed an automatic tool change system for the shrinker. We have got two cartridges outside the machine, one of which is preloaded with the next set of 16 segments. When the operator hits ‘tool change’ the machine ejects the old set, inserts the new one and locks everything down - all automatically in about 45 seconds.”

That innovation, also powered by SEW-EURODRIVE servo drives, has transformed productivity.

“We have reduced tool changing times significantly, giving our customers more production time per shift, allowing them to produce around 80 additional parts. With two or three tool changes a day, the gains are massive.”

The entire catalytic converter assembly cell can contain up to 30 SEW-EURODRIVE servo drives, powering and synchronising multiple machines – from laser measuring systems to robotic handlers. Behind the scenes, Jendamark’s proprietary Variant Manager software orchestrates these movements.

“Every part coming down the line is slightly different, so every 30 seconds a new set of parameters – such as diameters, spring loads and positions – is sent to the drives. There are no fixed positions, so it is completely dynamic, adapting in real time,” Naidoo says.

Parallel to this performance, he adds, is an equivalent focus on reliability as customers require minimal downtime to ensure that their processes and products remain viable. He notes that US-based customer Cummins (through its acquisition of Faurecia’s US factory), has been running Jendamark’s shrinker for almost six years - during which time it has produced over three-million catalytic converters.

“Apart from greasing the screws, there has been no major maintenance and no drive failures at all. That is a testament to the robustness of our overall design and of the reliability of SEW-EURODRIVE equipment.”

The customer was “so impressed” that it decided to standardise globally on Jendamark’s machines.

“They had two other suppliers’ machines next to ours on the same line. Now they’re replacing those with Jendamark machines, because of reliability and consistency of quality.”

SEW-EURODRIVE Gqeberha branch manager Phillip Steyn says the project exemplifies how advanced motion control systems enable complex automation.

“Our MOVIAXIS multi-axis servo system, combined with our efficient servo motors and dynamic gearboxes, provides the accurate positioning and torque that this machine needs.The challenge was to deliver very high torque while maintaining precise synchronisation and feedback at rapid speeds.”

Steyn notes that it is easier to be accurate when machinery is moving slowly but it becomes much more challenging in the context of  high-speed machines like this one. SEW-EURODRIVE’s control architecture ensures that every motion – from the synchronised pulling of the ring to the positioning of the auto-tool change mechanism – is tracked and verified before the next cycle begins.

“There is a great deal of feedback between the drive and the upper level controller. The system scans the input data – the product types and can sizes – and adjusts torque and position in real time. It is the brain and the muscle working together.”

Naidoo concurs, highlighting that the value of SEW-EURODRIVE’s integrated unit – the motor, gearbox and drive – is already matched for torque and speed.