4.1. Correlation matrix
When multiple tools are available and a rationale is needed to understand how they can be exploited for establishing CBMs, the first step is to correlate the results of the State of the art that enlightened the multiple CBMs and the LCES strategies.
It is important to note that a single, high-level strategy can be explicated in more than one LCES, likewise, each of the latter can stand under multiple value propositions.
Table 1 shows a summary of the outcoming correlation matrix, where only the value proposition for each BM is outlined. The column CBM introduction integrates information regarding how the innovative BM may be introduced in the corporation. The cases in
Table 1 relate to Acquisition and Diversification. The first refers to innovative channels and ways to sell (additional) products or provide services that enter into the running business. Diversification instead consists in selling/offering a value different from the traditional selling/buying model with the traditional business remaining in place. For example, the case of selling the maintenance kit falls in the case of Diversification because the traditional trading system is maintained, although additional products are added to the portfolio and are provided as a service. On the contrary, when a machine is remanufactured and provided for renting to new customers, this is the case of Acquisition because the CBM is acquired and placed next to the existing one, not in its support. Transformation does not appear in the table because potentially the identified CBM may be placed next to the traditional one.
The cycling strategy includes all those CBMs whose value proposition enable the establishment of (close) loops of use of resources, both as they are (resell/ reuse) and in a different state (i.e., reconditioned). The core of the value propositions accounted by the strategy extends the use of resources in a longer timeframe, through maintenance optimization, monitoring and control of the machinery.
4.1.1. Reuse- Resell
The Resell-Reuse strategy has multiple elements in common with Cannibalization, as both require a product to be disassembled, parts to be inspected and their selection to be re-employed, either for being re-sold or re-introduced in other products internally managed. The following tables are shown to describe in detail the content of the correlation matrix. The cells were filled considering the existing literature and the outcome of the literature research regarding the success stories of existing companies.
Table 2 shows the part of the customization matrix, related to the Resell-Reuse strategy. This is a strategy that can be either carried out by industries or private; however, in the current study only the first case is considered.
When attributing a piece to reuse or resell defect has to necessarily be classified, since the entities of the defects determine if a piece can be re-used, re-manufactured or must be discarded or employed in different sectors. Kin et al. [
63] propose to criticality rank an assessment of the defects. At the moment the decision is mostly up to worker experience: an extensive human intervention is required for feature recognition and knowledge interpretation [
64]; this makes the classification costly and vulnerable to human error. In this field AI can be very powerful to detect and cluster the status of components and make the process much more flexible [
65].
Similar considerations about product inspection and defect classification are valid also for other strategies, such as Pay per use, Remanufacture, and Refurbishment, as they all expect the product to return after the user discards it and inspected it to evaluate which strategy better fits the component/ product case.
4.1.2. Pay per use
In the Pay per use (
Table 3) strategy Machine as a service and Remanufactured machine as a service were included; the two value propositions are similar, except for the state of the machine that is provided. For more clarity, aspects that differ between the two CBMs are highlighted in different colors (cells filled in grey refer to remanufactured machine as a service).
In Pay per use strategy the product is designed, materials are acquired and processed to obtain the finished product. Then, multiple customers use it.
The service may be provided under multiple revenue models, as a rent of the good, or under a subscription (time-based or cycle-based fee). Both are PSS; however, PSS was not born to specifically support CBM: many organizations shift to PSS to dampen maintenance, re-manufacturing, up-grading issues, either from an economic or legal point of view [
66]. The customers interested in renting a machine, or endorsing a subscription for it, may either be users who already know the product or new customers. What they have in common is the need to pay for the machine only when needed and face a lower total cost of ownership and/or lower up-front investments; they are not interested in owning the good, but rather to have it functioning when needed, even just temporarily. As the product must be returned at the end of the subscription period, service and RL activities are crucial for the success of the Pay per use strategy, where modules and components must be analyzed once returned: the inspection site may be the same or different from the OEM site. To make RL economically feasible many factors must be optimized: i) the distance the product covers from the user to the facility to be reached; ii) the means of transport it will travel by (road, rail, air transport or ship), iii) frequency of batch shipping, iv) who in charged to pay (is the customer charged since the purchase of the shipment costs or these should be allocated to the downstream products?), v) stock management, taking into account the quantities of products aimed to be re-manufactured and re-used: will they be enough or additional new spare parts will be required? How to handle the floating availability of re-worked modules/components? – missing, late, defective, and non-available spare parts are a big challenge [
67] vi) cost of core acquisition [
68,
69].
By service operations all activities related to maintenance, repairing are included. In fact, when a customer gets a machine as a service instead of buying it, implicitly expects the machine to be always well functioning or whenever a failure occurs the user isn’t responsible for fixing it. When setting the fee, this is proportional to the guarantee ensured by the OEM and the limitations of roles and musts.
With running PSS the concept of delivery and Just in Time is partially modified. the service provider must be careful when balancing the number of machines offered and the demand. In addition to that, the capacity demand does not only regard the availability of machines for upcoming customers but also spare machines must be ready to be delivered in substitution of running machines that face stops.
Differently from the sale model, when a good is acquired by pay per use systems the user and the service provider may have multiple contacts; as a consequence, their relationship may last longer.
On a general base, the EoL is a crucial phase, also because it requires high volumes to be optimized. An impressive advantage in this sense is given by the Pay per use strategy. The organization that offers the machines for rent has three main strengths: it may reach the high quantities that a single use may not fulfil, even with big machinery; secondly, it can gain much experience in treating goods at the EoL; ultimately the big volumes may raise its role towards suppliers and all who may cooperate to close the loop, as gap exploiter, collectors, retailers).
4.1.3. Repair or corrective maintenance
Table 4 shows the part of the correlation matrix concerning the Repair or corrective maintenance strategy. This is a well-known practice, widely applied also in linear economy contexts since corrective maintenance is performed after a failure occurs, or detection of a fault; however, the boost of the Industrial Internet of Things (IIoT) and innovative practices can make this strategy more sustainable. First of all, organizations can be supported by companies that provide service of troubleshooting, to release them from the burden of failure and faults. Remote troubleshooting may have multiple advantages because not only time is saved, but also transportation and consequent impacts are lowered. AR and other KETs may be useful in easing maintenance activities. The corrective maintenance can be either adopted as an implicit service that comes together with a sold good or can also be apart from it and be offered as an additional service, whose extensions vary following the customer preferences (customized/ differentiated service packages). In the latter case, the customers who benefit from the packages may be both old and new customers. The size, the approach to maintenance, the location and multiple factors can influence the choice of adhering or not to the maintenance service; nevertheless, a key point is the availability of data, connection and sensors between who take care of the maintenance and the machinery. The supply of maintenance is widely accepted by the organizations, as they feel it is a non-core activity and do not wish to employ and increase expertise in secondary activities.
When dealing with machines, downtimes are a sore pain. Temporary unavailability of a machine can cause big losses. To avoid this inconvenience, enterprises recur to the stratagem to buy in advance (supposed) critical components, to store in their warehouses as spare parts. Beside the costs due to this attitude, problems can rise as spare parts need to be at the optimum state (i.e., electric motor). Being stored and not used can cause disorder (i.e., dirt, humidity) and missed functionality once the spare part is needed. The spare parts/module rent is a strategy that tackles exactly these circumstances: instead of being bought and stored in the customer’s warehouse, the OEM can offer the service of storing the spare parts, guaranteeing both their maintenance (also during the time they are not used) and rapid delivery when the module is needed. This practice has positive impacts both on economy and environment: the OEM managed a higher number of parts, thus may have convenient agreement for spare parts supply; secondly, the OEM arranges the needed number of spare parts and customers avoid buying spare parts that may never be used and get damaged without being used (resources saving).
4.1.4. Predictive maintenance
If machines are provided with sensors, data are analyzed and information about machine and process status is obtained, corrective maintenance may be anticipated, even in moments preceding failures. This is the case of Predictive maintenance, whose matrix is shown in
Table 5.
The BMs behind the different kinds of maintenance are very similar, however different are their value proposition and their objectives. While in Corrective maintenance failure may occur and any effort isn’t put to avoid it, in Predictive maintenance pre-planned tasks are performed. The acquisition of data directly from the shopfloor enables a huge range of activities, the tracking of usage lifetime among them. The phase of machine monitoring enables understand when and if a failure is about to occur; sometimes the monitoring may also avoid the failure, by anticipating the maintenance.
4.1.5. Time-based maintenance
Time-based maintenance is an additional recognized type of Preventive maintenance (
Table 6). It consists in restoring or replacing a component regardless of the condition of the product. The scheduling and management of maintenance may result in annoying and mode onto secondary activities, even though is crucial for the machine's safety. The supply of a maintenance kit may support enterprises. Through a subscription, the user can receive a maintenance kit based upon a set timeframe/number of cycles, so that it is known when to do ordinary maintenance and what is necessary to substitute/repair.
Both the waste hierarchy and CE have evolved to emphasize the design and use of a product before it turns into waste. Therefore, they share a joint philosophy, aiming to manage waste by rethinking, redesigning, remanufacturing and repurposing in order to improve the resource effectiveness of a product and to reduce the generation and adverse impact of waste [
70]. Depending on the status of the parts employed and the operated modules, the activities of taking old machines and restoring their conditions and functionalities or making new machines out of them refer to different LCESes and depend on the type and functionality of the products; for example, mechanical and electromechanical systems have to be separated from mechatronic systems [
71].
4.1.6. Remanufacturing
The market of remanufactured (
Table 7) (as for the reconditioned,
Table 8) can be tricky for an enterprise. From the technical point of view, there are multiple barriers, firstly because the status products come back after the use phase is unknown and unpredictable; this has direct consequences on inspection and disassembly times and costs. Disassembly automation can bring many advantages to disassembly tasks by applying the latest developments in I4.0 and cooperative and collaborative robots [
65]. Some studies induced a physical phenomenon under controlled conditions to ease product de-manufacturing [
72] or investigated eco-friendly approaches such as chemical ultrasonic treatment to separate all layers and components of electronic components [
73]. The Remanufacturing process may employ multiple technologies; very often a winning strategy is the combination of additive (such as electroplating [
74], welding [
2,
75], cold spray [
76], laser cladding [
77,
78]) and subtractive ones, i.e. Computer Numeric Control (CNC) operations as boring, turning, gross grinding, etc. [
79].
All those strategies that expect a partial action on the machine (i.e., Remanufacture, Refurbishment, Recondition) also require an inspection that enables the go-not-go decision. In the specific case of Remanufacturing, the parts or modules introduced come (if possible) from previously discarded machines (additional parts that enter the lifecycle).
4.1.7. Recondition
Besides difficulties, multiple are the benefits; among them: the customer faces lower initial investment, and resources are used more sustainably and efficiently. The lower price paves the way to the acquisition of new market shares, especially in the Recondition strategy, because the requirements of the customer may be different from the traditional one (a reconditioned machine may not fulfill the overall functions of the new machine).
4.1.8. Refurbishment
Different is the case of Refurbishment (
Table 9); in this case, especially in full machine refurbishment, the customer of the “old” and “refurbished” machine is the same. Besides the benefits deriving from the machine update, the user has also the chance to obtain a smarter machine from the refurbishment. In fact, refurbishing a machine can provide it with a technological upgrade; therefore, by facing little expenditure, the user gets an old machine that can be remotely monitored and switched on/off, connected to the industrial system.
Refurbish presents similar contributions to the Remanufacturing case, however the customer along the whole supply chain remains the same.
The machine refurbishment may require the product to be moved to the specific facility of refurbishment. However, the strategy of getting back in the box the spare parts, employs refurbished components, without moving the product. It consists in substituting certain damaged parts with refurbished ones; those that are damaged are sent back to the manufacturer, instead of being thrown away, so that the OEM decides whether refurbish or recycle them.
4.1.9. Recycle & cannibalization
CBMs can also support and push Recycle and recovering parts from returned products (
Table 10). What endangers recycling is the bad design of products (focused on functionality and manufacturing, not on EoL) and the lack of knowledge of the product.
The machine user may not be able to properly recycle the product because optimized recycling would require a partial disassembly: time, cost and inexperience make it ineffective and economically unsustainable. To gain many conveniences, the disassembly of a high number of machines is necessary. Dealing with high quantities of materials ensures higher refunds from recyclers, which may bring consistent incomes. Thus, the value reported in the table expects the machines to be collected after the use phase, properly disassembled (by selective disassembly) and materials sorted in flows to optimize recycling.
The potential revenues from conferring the properly differentiated materials should exceed the costs of disassembly and refund of the customers. Similarly, the cannibalization strategy aims at recover parts of the products before they are recycled.
Therefore, this CBM may be coupled with others, such as those involved in Reuse-resell, Refurbishment, and Remanufacturing strategies, because they also require the machine to be re-collected after the use phase. So, first, the parts of the machines are allocated to other machines or reworked, and the remaining resources are sent to recycle.
4.2. Business cases
The methodology presented, supported by the correlation matrix that has been developed, found application in two industrial cases. One organization is a small-medium German enterprise active in the machining sector and designs, produces and commercializes welding machines. The second is a large Italian enterprise and designs, produces and commercializes machines for wood- and metal-working.
Both the German and the Italian companies belong to the machinery construction sector, namely they are OEMs. For the sake of discretion, in the following they will be referred to as Company A and Company B respectively.
Company A’s clients are mostly large companies (B2B market) and belong to a niche market (mostly limited to automotive/industrial plants); however, they are located worldwide. Though the company currently takes care of the machine whenever damage occurs, there is no EoL treatment, neither it is known what happens to the machine when this is discarded. Company A provides both machines and after-sales services; its value proposition may be summarized as follows: To provide a high quality, durable friction welding machine that meets the customer’s needs in terms of welding application and has the right dimensions. Compared to its competitors, the small size of the company allows for a different cost structure and therefore a cheaper offer. Revenues are generated either from the sale of the welding machines, but also from the sale of spare parts for critical components (e.g. welding head), the machine maintenance (head, motor, spindle) and small series production of welded components. Each machine requires a large number of laboratory tests before production and is characterised by a high degree of customisation.
As far as Company B is concerned, the value proposition can be stated as follows: To providing reliable woodworking machines, and support in the maintenance phase through after-sales service and the supply of spare parts. The customers of company B are located worldwide and can either be amateurs (B2C) or industries (B2B), ranging from small carpentry shops to large enterprises. They are offered the opportunity to configure their machines based on the proposals contained in the product portfolio, but they can also choose to upgrade or add customised options. The larger the machine, the more likely it is customised. Company B is part of a group and several enterprises in the group are close partners. The highly customised solutions lead to the acquisition of several patents every year; this is a way of protecting the acquired know-how and the technology. Differently from Company A, which develops direct relationships with the customers, Company B relies on dealers or a separate commercial entity (belonging to the group) to reach customers. Consequently,established relationships are mostly indirect, with a few exceptions. Nevertheless, long-term relationships are established.
In both cases, the companies did not manage the EoL of the machines, nor did they obtain environmental or social certification.
The two companies present different characteristics (size, machine damage management, relationship with customers); the implementation of the proposed approach interestingly proves its wide applicability. Both organizations rely on external and in-house resources to develop digital solutions. Several tools have been developed and exploited aiming at getting information about the status of a product and its components during its life cycle, the remaining useful lifetime, in order to extend it while keeping any action economically sustainable. For each tool, the main functionalities have been firstly investigated. This paved the way to the assignment phase: every CE-driven LCES was retrieved, and the tools were identified as core resources and capabilities of the strategies. One tool might be useful for more than a single strategy; it may also occur that a strategy is not enabled by any tool.
Figure 3 graphically summarizes the main outcome of the assignment phase. Four LCESes were considered (Pay per use, Re-manufacturing, Refurbishment and Predictive Maintenance). The blue and green circles mark the strategies that refer to BM acquisition and BM diversification respectively. Predictive maintenance is the strategy all the tools can support. The Pay per use is enabled by the prognostic and health management toolkit and the data repository and knowledge discovery tool.
Both organizations were provided with multiple tools; the analysis of the current BM revealed that the business is closer to the traditional BM than the circular ones. Besides some activities focused on digitalization, such as the machine connectivity of company B, where digital services are provided through standard platforms and add-ons, maintenance, EoL management, and value offers are still bounded to traditional schemas, when available. Therefore, not a single CBM has been exploited, rather roadmaps were defined for each company, presented in
Figure 4.
The roadmap is customised, according to the current status of the company. The very last strategy is the Pay per use; however, several intermediate BMs were identified. The main potentialities of the roadmap stand in:
By defining and respecting the roadmap, innovative and new approaches and activities can be introduced progressively, without hampering either the already running, or the new markets. In addition to that, a gradual change allows for a smoother and more seamless introduction of new roles and partners.
The roadmap supports the enterprises introducing digitalization tools and practicing the management of the used products they sell. First, the focus is on the optimization of the maintenance of the running machines. This can happen in situ, where the machine was produced, or where the machine is installed and the failure occurs. The main goal is to detect in advance potential failures and monitor the status of the machine so that the wealth of the components and modules is known. This first step requires the support of roles previously unnecessary, such as services providers, hardware suppliers, and data analysts.
After well managing traditional maintenance, which can be supported by innovative tools that decouple the physic machine and the maintenance operator's actions, predictive maintenance can be investigated. In doing so, it is necessary to be provided with a classification of machine status and failures mode and causes, so that off-standards events can be detected, and unexpected failures avoided. Knowing the status of the machine and being able to handle and interpret unexpected behaviors pave the way to the modeling of a digital twin of the product, to monitor its performance; consequently, whenever the customer wants to discard it, the resources contained in the machine can be exploited at best (i.e., the best lifetime extension strategy exploited). This mastery leads to alternative models to provide goods: as a service, rather than as a product.