Circular economy opportunities in the European machine tool sector
A recently published report on the European machine tool sector, conducted and published by the European Association of the Machine Tool Industries (CECIMO), defines the sector as an industry having high potential to benefit from circular economy practices and approaches.
The study asserts that the shift towards a circular economy calls for a prominent role of manufacturing in which the machine tool sector plays a crucial role.
“Machine tools already have multiple lifetimes and embrace some key principles of the circular economy. But there is always room for improvement. The sector can invest in advanced manufacturing technologies, but also build upon the existing good practices. It will improve productivity and resource efficiency, while consumers will enjoy products that last longer and use less energy”, the report says. In the following article we have selected and present to our readers some of the key conclusions of the study.
A logical solution
The report reviews machine tools as essential assets for sustainable manufacturing. The aim is to allow for the long life, optimal reuse, refurbishment, remanufacturing and recycling of products and materials. Many of these aspects are already present in the machine tool sector. CECIMO studies to what extent are machine tools already circular products and contribute to the circular economy. The Association notes that Europe imports six times more materials and resources than it exports, and resources make up the largest part of companies’ costs. “To keep Europe competitive, we need to maximize resource efficiency and put the materials contained in our waste back into productive use. We need to replace virgin materials with recycled secondary raw materials, in a circular manner, on a European scale”, the organization recommendations say.
CECIMO reminds that taking a sustainable path requires fundamental changes throughout the value chain, from product design, production processes and business models to consumption patterns, waste management and the use of secondary raw materials. This in turn calls for technological, financial, social and organisational innovation, with new forms of governance that enable and encourage public and private actors at all levels to play their part.
Overview of the sector
The machine tool industry is presented as a key enabling sector having a direct impact on the productivity and competitiveness of European manufacturing and in the transition to a more circular economy. Among the main characteristics of the machine tool sector is its heterogeneity in terms of company size, as well as the use and type of machine tool products.
“The average European machine tool company is a Small or Medium-Sized Company (SME). Despite the fact that the majority of European machine tool companies are SMEs, the machine tool market is highly export oriented. 77% of CECIMO member countries production is shipped abroad, whereas around half – 52% in 2017 – is exported outside Europe, mainly China and the USA. Therefore, machine tools are produced for a global market and, in some cases, Europe is not the main source of sales”, official statistics show.
European manufacturers are focused on high-end, customized machines with a relatively long production cycle, as opposed to standard machines with short lead times, CECIMO adds. The European machine tool industry is the leader on the global market, with a highly innovative, diversified and precise production programme. Manufacturing companies have kept their global market share at around 33% of the global machine tool market in recent years, but they are facing increasing competition from China, Japan or South Korea, the report also finds out.
Machine tools are one of the product groups that have been considered by the European Commission for the establishment of ecodesign requirements. In this context and in preparation of a possible Ecodesign self-regulatory initiative, CECIMO carried out in 2009 a Life Cycle Analysis (LCA) of two types of machine tools – milling and turning machines.
“Nine machine tools – ranging from five tonnes to nearly 100 tonnes in weight, from five companies in Germany, France and the UK – were considered for this assessment. The LCA concluded that the most significant environmental impact of machine tools occurs during the use phase compared to other phases such as, construction, transport, installation and dismantling. Moreover, the consumption of energy during the use phase is by far the most relevant environmental aspect of machine tools over their life cycle.
These conclusions have been confirmed by the preparatory study on machine tools carried out in the framework of the Ecodesign Directive”, the Association reminds.
Other variables such as precision, speed, reliability or flexibility have been traditionally considered the main factors when purchasing machine tools. In the last few years the industry has been seeing an increasing focus on environmental aspects such as energy efficiency.
“Machine tool manufacturers can influence the energy efficiency of a machine tool during its design phase, but user behaviour plays a major role in the actual energy consumption and performance of the equipment. Therefore, in addition to the introduction of measures contributing to energy efficiency during the design phase, it is also important to support the machine tool user during the use phase. In this respect, many machine tool providers already give recommendations to end users in instruction manuals, relating to procedures connected to energy efficiency (e.g. correct maintenance and avoiding overloads), or they provide specific training to ensure optimum performance of their equipment”, the report further says.
Researchers note that the amount of energy supplied to a machine is not an adequate indicator of its energy efficiency, especially in the case of complex products like machine tools. “To determine the energy efficiency of a machine tool, energy consumption needs to be considered against the results achieved – for instance, the number of workpieces produced, their shape, quality, accuracy and other relevant factors that are determined by the specific application. Moreover, the strong individuality in machine tool design, applications and other factors means that it is not possible to define general energy efficiency measures that are effective for all types of machine”, CECIMO adds.
Since 2009 the machine tool sector has been working on international standards to assess the energy efficiency of machine tools, supported by the International Organization for Standardization (ISO). The standard contains a list of possible energy efficiency improvements, whose effectiveness and application would then need to be considered in view of the specific system, functionality and technologies of the machine tool under evaluation.
“The ISO14955 standard series proposes analysing machine tools from the perspective of the different functions they execute, e.g. the machining process, tool handling, and machine tool cooling. According to this ISO standard, all machine tools can be characterised by six general functions. The functional description of machine tools is general and independent from the design of the machine tool and the machining process. This allows for a generalized approach for a wide range of machine tools to evaluate their environmental impact”, the study explains.
The functions described in the standard are carried out by various machine tool components, such as hydraulic pumps, cooling units, spindle drives and so on. Each of them contributes to the total energy use of the machine tool. By mapping the components to the different functions and evaluating the share of energy supplied to each of them, it is possible to identify the components that are relevant in terms of energy use, researchers find out.
ISO 14955 provides a very useful resource for machine tool designers who wish to maximize the environmental performance of a certain machine, while keeping in mind its specific application. It also supports this energy-saving design methodology by providing practical methods for measuring the energy supplied to machine tools.
The role of recyclable materials and waste products
Machine tools are mainly made of metallic materials – cast iron, welded steel, etc. They are very diverse but, in general, around 83% of the machine is made of metallic materials. “These materials are easily recyclable and can be used to produce new products again and again with no loss of quality. Metal components are also valuable, and this means that there is an incentive for metal to be recovered during the disposal of machine tools at the end of their lifetime - either by the manufacturer or by scrappers”, the study underlines.
As far as the metal working processes are concerned, cutting fluids and metal chips are the most relevant waste products generated during the use phase. Metal chips are normally separated from cutting fluids and then recycled. In addition, cutting fluids can also be recovered from metal chips and reused.
Among the novelties in this field are bio-based lubricants, which are already available in the market. They provide the same or even better performance than petroleum-based lubricants. To reduce the use of cooling lubricants, dry machining and minimum quantity lubrication (MQL) have also been explored as options, but this can negatively affect energy consumption and tool wear, CECIMO experts claim.
Modular pieces of equipment with several uses
A key element of a circular economy approach is the long life, reuse and remanufacturing of products. The main purpose is to keep them in use for as long as possible. In this regard, machine tools represent an ideal field for applying circular economy approaches since they are products with a long life. Many models are used for more than two decades and then completely refurbished and reused. Given their relatively high value, the refurbishment and remanufacturing is very common. Options vary from small improvements to full rebuilds, which incorporate full automation and control systems.
“According to available figures, in Italy, the average age of the total installed machines in 2014 was 12,8 years and, in Germany as of 2015, the average age of computer-numerically controlled (CNC) and non-CNC machines was 10,5 and 19,7 years, respectively. Data provided to CECIMO by some machine tool manufacturers also shows that, on average, 80% of machines are still in service ten years after installation, while 65% are still in service after 20 years. This information provides evidence of the durability and long-life span of machine tools, but it is also important to recognise that, on the other side, advanced manufacturing technologies are always evolving, and a long lifetime may also translate into an extension of the lifetime of machinery with lower efficiencies and productivities”, the report informs.
Machine tools usually have modular design. To reduce downtime of the machine in case of problems, manufacturers make sure to provide access to key components for replacement. This simplifies maintenance, helps to reduce construction costs and facilitates remanufacturing and disassembly at the end of life. When a machine tool is remanufactured, it’s important to make it possible for newer and more energy efficient components or controls to be added. This may lead to a distinct reduction in the energy consumption of the whole machine.
“According to data from the Ecodesign preparatory study on machine tools, 80% of machine tools are retrofitted and refurbished when they are between 5 and 15 years old depending on the specific sector and application. Finally, it is important to highlight that although it is difficult to find specific data, the second-hand market for machine tools is also very important”, the study concludes.
Extending the machinery service life
Quality strongly depends on the condition of the equipment. Digitalization and the permanent, remote monitoring of machinery condition makes it possible to reduce downtimes through the early detection of possible problems prior to asset failure through implementing predictive maintenance. Predictive maintenance increases product reliability and availability and enables users to extend the lifetime of products.
“According to various studies, the use of predictive maintenance enables us to decrease total machine downtime by 30-50%, while increasing the machine’s lifetime by 20-40%. But equipment data does not only increase the efficiency of maintenance operations, it can also help in the remanufacturing of products. Having the data history of the machine means that the manufacturer knows the wear and tear of each component. It is therefore easier to identify which component needs intensive work or replacement and which one needs some small adjustments or no repair at all”, the Association points out.
Benefits of additive manufacturing
Additive technologies have significant advantages over conventional subtractive machining methods. Benefits come in terms of design freedom, mass customization, innovative business models, etc. A key aspect of AM is its potential to support the move towards a more circular economy.
Lightweight design and enhanced durability and functionality of components are a major opportunity, which AM makes possible. Technologies in the field have very limited shape and geometric constraints, allowing the production of alternative optimized complex parts which have a lighter weight and improved functionality. This can help reduce the consumption of energy and natural resources during the use phase of the final product, leading to a positive impact on the environment.
“An example of such functional improvement can be found in lightweight components for transport systems. AM-produced metal parts can, in some cases, be up to 50% lighter than machined parts. In areas such as aerospace or the automotive sector, the use of AM can translate into a positive effect on the environmental performance of the product during its use phase”, CECIMO explains.
The nature of the AM process allows the creation of new material structures that can boost the properties of the components being fabricated, e.g. increased strength, stiffness, corrosion resistance, etc.
“Additive technologies can also help reduce waste in the production process, since they only use the material that is needed to produce a part. AM can play a very important role in the circular economy by making repairs and remanufacturing easier and more cost-effective. AM allows spare parts to be printed on demand and closer to where they are needed. This helps reduce inventory waste and customer waiting time”, the study reports.
Digitalization in the sector
Digitalization is transforming the whole manufacturing industry, including machine tools. The trend towards advances in data, analytics and connectivity today makes sustainable and resource-saving manufacturing more easily achievable than ever. According to a study by the International Energy Agency, real-plant data showed that energy efficiency gains from the application of advanced digital process controls can lead to significant savings with little-to-no net costs.
“Improvement in the collection and use of data makes it possible to optimize business operations, maximize energy efficiency and use fewer resources more efficiently. Digital technologies are therefore pivotal in bringing about a change towards a more circular manufacturing sector. Digitalization is making the consumption of resources easier to measure which means that processes with excess energy and resource consumption can be identified and optimized”, the European Association of the Machine Tool Industries concludes.
Digitalization also allows the creation of digital replicas of physical assets, called digital twins. They represent virtual models of physical assets such as machines in operation or even a whole production process. The twin provides a connection between the physical and the digital worlds.
“Digital twins of products, such as machine tools, can be used by manufacturers to analyze the actual product behaviour in relation to its original design. This allows us to recognize any behaviour deviations and to influence the development of future products. Moreover, by simulating and validating product properties of a manufacturing system on a computer, prior to physical production, the amount of physical testing and experiments can be significantly reduced. This does not only enhance the ability of industry to innovate and to reduce the time necessary to put new products on the market, it also helps to optimize products in advance and to reduce the resources needed for their development”, the report underlines.
Source: “The European Machine Tool Sector and the Circular Economy”, CECIMO, 2019
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