## 3 Results
### Synthesis: The generic Product Lifecycle Model (gPLC)
Realization means roll-out and deployment. For services, preparative actions are performed in realization, including, for instance, training of people. Service delivery might be started in the pre-sales phase already. An important point in time is the end of production, i.e., the completion of the whole product class. Production might be stopped even though product instances are operated for a long time beyond that. Service delivery is prolonged up to after-sales. Spare parts are produced and delivered by the OEM or service providers (cf. end of delivery obligation/EDO). For software products, maintenance has to be ensured, while updates can be rolled-out. The transfer phase into a succeeding cycle is often called decommissioning. It means to decommission physical assets, to finalize service provision and to remove software deployments. When aligning these processes, both risk factors and opportunities can be identified. Creating a new product-service system means to coordinate the involved disciplines and service management with logical and temporal relationships. The objective is to bridge discipline-specific methods with multi-disciplinary approaches. Chances shall be utilized. For instance, software engineering can be conducted in short cycles of a few hours with debugging leading to thousands of error messages to be handled. In contrast to that, engineers in mechanical engineering need to configure simulations or even manufacture prototypes for model analysis in the range of days and weeks. Additional engineering loops shall be avoided by explicit countermeasures, such as aligned terminology, methodology and model management. Differences between disciplines imply that within a product-service system's life, there might be more than one cycle of the material core product and a multitude of cycles of its software elements. These are considered inner multi-cycle relations in the gPLC (see Figure 8). Outer multi-cycle relations link the product-oriented perspectives with overarching perspectives, such as material and technology as well as, for instance, plant lifecycles, including land use and buildings. Figure 7: Alignment of technical disciplines and servicing under the hood of the Product Creation process, based on the intrinsic gPLC concept and extended by indications of material and information circularity (linear visualization for the purpose of clarity). In all phases, innovation impulses can be brought in. Strategic planning is dedicated to this objective, but in addition, innovation is possible along the entire lifecycle. Specifications of the product and process can be enhanced later during realization or during operation time or recycling. For instance, during realization, a company can switch production to an advanced manufacturing technology, which is not yet available on a robust level during the original engineering phase. In many cases of demanding technical systems, such as cars, aircrafts, industrial assets, the operation phase spans the longest time period of up to decades. Technology and material lifecycle models can be linked with the gPLC. These are typically structured into the research phase, commercialization, utilization and replacement. Additionally, CE means to put emphasis on the EoL phase right from the BoL. Nonetheless, there is a significant economic benefit in monitoring EoL opportunities throughout the whole product life. In Figure 9, the differentiation between product class and instances is detailed. Economic lifecycle models, which highlight financial indicators, can be interpreted in terms of instance volumes. Instances are predominantly created in the realization phase. The number of instances increases according to production outputs, while at the same time, single instances are decommissioned step by step, leading to a reduction in active instances. These instances are typically treated as waste, turning into the product recycling. The cumulated sum of product instances represents the amount of input for recycling.