Simply switching to a polymer bearing from a stainless-steel bearing has saved a lead acid battery recycler, Fry’s Metals thousands in maintenance costs, and far more in preventing lost production time.
Recycling lead batteries in high volume is a tough, corrosive working environment to work in. As such, one of South Africa’s leading lead recycling companies, Germiston-based Fry’s Metals, had grown accustomed to losing up to four days of production per month due to the recurring premature failure of critical conveyor idler bearings.
That was until plant engineer, Erasmus Smit, examined the physical requirements for these stainless-steel bearings and tried other options to prolong the operational period between bearing changes.
Having experimented with various stainless-steel types, and ruling out other materials, he turned to polymer bearing specialist igus to find a solution. With the help of igus product engineers, the team determined that an igubal JEM insert bearing was the ideal substitution due to its high load handling ability. high abrasion resistance and chemical and corrosion resistance, key factors in such a punishing environment.
New, better bearing leads to more improvements.
“Ultimately, when the last stainless-steel bearing failed, we stopped the conveyor and split the belt to access the bearing, we found the shaft was damaged and in need of refurbishing due to the bearing failure and constant abrasion,” says Juan-Eric Davidtz, product manager at igus “Once the shaft was replaced and the new igus bearing inserted into the existing steel housing, we had a specialist technician resplice the belt and restart the process – that was five-months ago, and we have not changed anything since.”
Making this simple but effective improvement has had a knock-on effect at Fry’s. “While the part cost just around £9 it has saved us a fortune in downtime prevention and has greatly improved the overall productivity of the plant,” Erasmus Smit says. “This success has also led us to seek other areas for improvement where we can use igus bearings and other motion plastics solutions to replace steel throughout the plant.
“We have already identified a number of applications that will benefit from these wonder-materials – including bearings, linear guides and cable management solutions,” he adds. “Considering that our whole business is built around the smashing and recycling of batteries containing aggressive acids, needless to say that only the toughest materials will do.”
Treasure from scrap with tight environmental controls
Fry’s Metals’ recycling process includes collecting car and other vehicle lead acid batteries which are stockpiled and loaded into a chute by means of front-end loaders. This usually leads to substantial damage of the battery casings. The chute releases the mostly broken batteries onto an inclined conveyor, which transports the material to a specially-adapted hammer mill – leaking acid all the way.
The strong acid – with a PH value of about 3 – spills over the conveyor and passes into and throughout the rest of the process. The batteries are further pulverised and the lead extracted. Other processes lead to the plastic being recycled and the lead smelted, with both materials’ quality checked and prepared for resale to battery manufacturers.
The entire process is physically demanding and corrosive and requires high levels of safety and environmental management to prevent accidents and damage to the environment. By reducing the human intervention these more efficient engineered materials contribute to an all-round cleaner and more sustainable process.
“This customer story is a great example of igus solving technical problems and giving a cost reduction,” says Rob Dumayne, drytech director at igus UK with responsibility for all bearing products. “People know igus well for lubrication-free plastic bearings. But our USP is also in the research we conduct on polymer properties so that we can offer customers like Fry’s Metals the right product in a tested, chemical and acid-resistant polymer like igubal JEM, with no negative effects on its performance for the task.”
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