Innovative technology for ‘shrinking’ catalytic converters designed and built in South Africa by Jendamark Automation for the global market, uses SEW-EURODRIVE’s servo-geared units and motion control software for its precision operation.

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.

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

Yanesh Naidoo notes that 95% of the locally produced machines are exported and are in operation in Europe, India and the US.

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, he explains.

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

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 microns 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,” Naidoo says. “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.”

Two SEW-EURODRIVE servo motor systems are used to drive that motion, each connected to precision roller screws that pull the ring from both sides to ensure synchronisation of the drives.

“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.”

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.

That innovation is also powered by SEW-EURODRIVE servo drives, and has transformed productivity, he says.

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