Many bearing points are protected against environmental influences and wear by so-called loss lubrication, where grease is pressed out from inside the machine and enters the environment. This is said to result in 27 million tons of lubricating grease released worldwide every year. More environmentally friendly oils and greases are an option, but these can be cost-intensive.
The other aspect of lubrication is that it cost-intensive from a personnel standpoint, as qualified workers are required for proper maintenance. So, in addition to the pure costs of the lubricant, the maintenance costs must be weighed. While lubrication and maintenance work is carried out, the machinery is unavailable, adding more expense to the overall equation.
Complicating things even more, some industry surveys show that 35-50% of all bearing damage occurs due to improper lubrication. When users are faced with unplanned machine downtimes, equipment manufacturers are confronted with complaints that are difficult to resolve and often cause financial difficulties and damage to their image.
Cologne-based igus (with its American headquarters in Rumford, R.I.) recently worked with RWTH University in Aachen to assess how customers using plastic bearings are faring versus these sorts of lubricant costs for metal mearings. While igus has long touted the environmental benefits to using these motion plastics products, the company wanted a third-party research study to see whether getting rid of metal bearings — which use grease and require more maintenance — was beneficial for manufacturers.
The the study’s results, unveiled at this year’s Hannover Messe trade show, were impressive. RWTH surveyed nine manufacturers, mostly in Europe, to determine what savings they were seeing from the use of plastic bearings: CNH Industrial, GMC, Wacker Neuson, Heineken Brasil, Krones, Lemken, Huppenkothen, Rockinger, and KettenWulf. The bearings’ applications were wide-ranging, including trailer systems, hinge joints, conveyor belts, escalators, mini excavators, and chain drives.
We spoke with Christian Lürken, Project Manager at the Manufacturing Technology Institute at the RWTH Aachen. First, his group did a study regarding the ecological impact of the production of the ring bearings.
“After that first study, the question came up about evaluating the whole lifecycle … so, for the second study, we interviewed customers that use ring bearings,” he said.
The study took roughly six months. Lürken said that they conducted interviews with 16 customers. Given that some companies didn’t have (or wouldn’t supply) the proper data, they narrowed it down to eight companies willing to be interviewed and had the right amount and kind of data.
“Here, we found out that by using plastic bearings, you’re able to have a sustainable use case where sustainability doesn’t come with costs — but comes with cost savings, so there is ecological and economic potential. There were some use cases where the savings were not that large. And there were some where we could really see some scalable effects, where a large amount of ecological savings could be generated,” he said.
“First of all, we looked at the individual use cases and evaluated them. We took data regarding how much lubrication was used before switching to igus plastic bearings, how much lubrication was needed for each maintenance cycle, how often was maintenance necessary? Then we added the lifecycle assessment, which is a standard scientific method where we use software to model the different locations.”
“We modeled this in the software so that we can calculate the ecological impact factors of the lubrication that is needed for metal bearings. Then for the industry, we added up and researched for each use case — for example, if we had a use case regarding tractors, how many tractors are there in Germany? How many are being produced? How many are on the market? We tried to figure out the values and then we scaled it up to see how much savings could be generated if 30%, 50%, or 100% of the tractors would use plastic bearings,” Lürken explained.
What’s next for sustainability in manufacturing? Lürken thinks that one big challenge regarding stainability is transparency.
“There needs to be transparency about your processes, about your products. How much ecological effort is required to produce a product? How much impact does it have?” he said. “Then you’re at the point of examining where you can optimize your process and your product and look at your use phase and end-of-life scenario. What is the possibility of recycling your products? How much ecological effort is required to recycle? At a certain point, can you remanufacture it? Then you can have a smaller impact, where you can renew the product through remanufacturing and use it again for a second lifecycle.”
Filed Under: Bearing Tips
