CIRCULAR ECONOMY | INSIGHT
In remanufacturing, existing, used components are
systematically reconditioned in an industrial process and reassembled into a new product. Unlike a refurbishment, for example, the result achieves at least the quality level of a new product, thereby enabling another life cycle. This has ecological, economic and social benefits:
on the one hand, material consumption and negative effects on the environment can be reduced significantly; on the other, costs can be lowered. For this reason, prices for reconditioned products are generally lower than those of equivalent new products. Current economic and political conditions and trends such as sustainability and strained supply chains have meant the acceptance of remanufacturing measures has been increasing for years.
REMANUFACTURING TBMs For several reasons, remanufacturing is particularly suitable for TBMs: firstly, they are subject to a high level of wear and tear in practical operation underground; secondly, TBMs are generally custom-built machines designed to meet specific requirements. Herrenknecht, for example, has delivered around 1,500 machines in the 50-year history of the company because, as is widely known, TBMs are designed differently for every jobsite and requirement. So, the machine is not normally ready for use again immediately on completion of a project. Machines used for multiple assignments without any
structural changes, on the other hand, are the exception, for example when constructing identical cable tunnels for a few wind farms. But even these must be overhauled and at least partially reconditioned between deployments.
GENUINE BENEFITS Against this background, the remanufacturing of a TBM is particularly interesting for the user and for three reasons: time savings; sustainability; and, cost- effectiveness. ● Time savings: tunnelling projects are often under high deadline pressure. This makes it even more important for the TBM to be available as quickly as possible. Here, the use of existing components offers decisive time advantages, as they do not have to be laboriously manufactured and potentially delivered as well.
● Sustainability: using components multiple times reduces the ecological footprint, as greenhouse gas emissions are significantly lower. A master’s thesis carried out at the German Pforzheim University in 2021, in collaboration with Herrenknecht, quantifies this effect precisely: On average, 71.42% of emissions can be avoided per tonne of remanufactured material, compared to the production of new material. Here we consider the CO2
equivalent (CO2 e). These results
have since been confirmed by certifier TÜV Süd and verified in relation to the requirements of DIN EN ISO 14040:2009, DIN EN ISO 14044:2006 and DIN EN ISO 14067:2019.
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● Cost-effectiveness: finally, the result of remanufacturing is cheaper than a new machine. However, given the high level of work required, these effects are not as high for TBMs as they might be for other, less complex or sophisticated products.
DEFINITION AND MINIMUM REQUIREMENTS But what exactly does ‘remanufacturing’ mean? At first glance, the term seems to speak for itself. A , for example, provides the following
recent textbook1
general definition: “Remanufacturing (refabrication) is an industrial process in which used products are restored to a condition comparable to that of a new product through disassembly, cleaning, reconditioning and testing.” However, the exact meaning is regulated not least by
industry-specific specifications and guidelines. For machines used in tunnelling, this is the ‘ITAtech
Report n° 5-V2 – Guidelines on rebuilds of machinery for mechanized tunnel excavation’ 2
. This set of rules,
published in 2019 by the International Tunnelling and Underground Space Association (ITA-AITES), also specifies two defined levels for TBMs, which represent different degrees of rebuild and service life extension, namely ‘refurbishment’ and ‘remanufacturing’. ● Refurbishment is the lower level. The result is a service life extension through comprehensive maintenance, repair and replacement of defective parts. The machine is made ready for use in a functional condition for similar subsequent projects without creating a completely new life cycle.
● Remanufacturing, on the other hand, is a higher value level aimed at a completely new life cycle. The machine or its components are completely disassembled, cleaned, checked, modernised if necessary and then reassembled in as-new condition. It is suitable for projects with high requirements and a long service life.
Below:
In supporting the circular economy, ‘Reman’ differs from refurbishment and provides built-in sustainability for TBMs
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