# The Future of Factories: Different Trends
## 4 Characteristic of Cloud Manufacturing  
_Cloud manufacturing_ is an emerging trend popular in China, which benefits from cloud computing and information technology to achieve resource-sharing across small and medium-sized enterprises (SMEs). It has become a national trend due to rapid industrialization and the advancement of information technology. Cloud Manufacturing can be defined as a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable manufacturing resources (e.g., manufacturing software tools, manufacturing equipment, and manufacturing capabilities) that can be rapidly provisioned and released with minimal management effort or service provider interaction [33]. Therefore, on-demand services, resource virtualization, and decentralized services of centralized resources promote new networked manufacturing forms to respond quickly to unpredictable demands of the market. Cloud Manufacturing inherits the concept of \"everything is a service\" from cloud computing. It proposes a new paradigm of _Manufacturing as a Service_ (MaaS), which encapsulates manufacturing assets (software tools, production systems, capabilities) into cloud services providing on-demand access to consumers. Further, cloud manufacturing promotes a new collaborative manufacturing business model, represented in Figure 6. Collaborative cloud manufacturing promotes the active role of the customers during the production process. Customers interact with manufacturers via a cloud platform by specifying their product requirements. Mass customization of products is enhanced by creating a network of enterprises Distributed Manufacturing Systems (DMS), having different roles in the production process. The nature of services provided in the cloud is extremely variegated due to the necessity to cover the traditional manufacturing processes and the related products life cycle. According to [35], service delivery models (SDM) are typical of Cloud Computing, and they can be divided into: _Infrastructure-as-a-Service_ (_IaaS_), _Platform-as-a-Service_ (_PaaS_), and _Software-as-a-Service_ (_SaaS_). In contrast to traditional cloud computing, services are provided both by cloud computing resources and manufacturing resources (smart robots, production systems, equipment). Services provided by the cloud can range from pure manufacturing services (i.e., equipment for product realization) to manufacturing software services (provided through a cloud computing resource). Cloud delivery models fit accordingly to the different manufacturing steps. As an example, considering the product life cycle, the following delivery models are suitable for the different production stages:  
Figure 6: Collaborative cloud manufacturing model taken from [34]. * Product Design, Product Simulation, and Product Management delivered as _SaaS_
* Product Planning delivered as _PaaS_
* Product Realization (requiring the use of physical equipment composing the factory floor) delivered as _IaaS_  
In addition to the standard cloud manufacturing _services_ mode, cloud manufacturing promotes a new form of enterprises collaboration through the on-demand access of virtualized and decentralized resources via a cloud platform. For example, virtual enterprises set up a collaborative network that supports a different form of coupling, such as _loose_ and _tight_ coupling. According to the diverse enterprise needs, loose coupling is selected for occasional use of manufacturing assets, while a tight coupling is chosen whenever a global manufacturing process relies on services offered by multiple enterprises. Therefore, a cloud architecture promotes enterprise collaboration by enabling multiple forms of alliances according to diverse needs. Through the unified management of resources/capabilities, cloud manufacturing promotes the sharing of decentralized resources of manufacturing resources/capabilities highlighted by the manufacturing grid and includes integrating and sharing hard manufacturing resources.