Abstract:     Service derivation has become an important strategy for manufacturing enterprises to obtain competitive advantages. Compared with the independent provision of products or services, the hybrid offerings can achieve greater value co-creation for supply and demand. As modular derivative service components are continuously embedded in hybrid offerings, the structure of hybrid offerings has become more complex and the knowledge content has sharply increased, which arouses the attention of manufacturing enterprises to knowledge management after the provision of hybrid offerings.In order to obtain more service opportunities and prevent knowledge leakage, manufacturing enterprises usually block the two types of hybrid offerings knowledge: (1) Profitable knowledge is conventional knowledge, related to services such as accidental failure handling, immediate operation & maintenance and functional repair. Profitable knowledge is external knowledge of hybrid offerings with explicit and practical characteristics, and customers can directly obtain it through learning or interacting with manufacturing enterprises. (2) Protective knowledge is unconventional knowledge, related to product structure and technological transformation. Protective knowledge involves enterprises′ intellectual property, which has tacit and value-added characteristics, so that customers usually cannot directly obtain unless manufacturing enterprises share it. However, knowledge blocking restricts the innovation and value creation of hybrid offerings by customers, which deviates from the goal of value co-creation for supply and demand through service derivation. Therefore, reasonable knowledge sharing can increase customers′ willingness to pay for hybrid offerings and customer utility, which caters to the vision of open innovation and alliance knowledge sharing advocated by the service economy. But in the meanwhile, knowledge sharing will bring the risk of knowledge spillover and accelerated diffusion, which may weaken the competitiveness of enterprises, and make enterprises easy to fall into the sharing paradox. Existing literatures have analyzed the knowledge blocking of manufacturing enterprises and designed knowledge sharing contracts, but the strategic choice of knowledge blocking or sharing after the provision of hybrid offerings is currently inconclusive. It is still necessary to further analyze the impact of knowledge blocking and sharing on the value creation for supply and demand.Manufacturing enterprises implement a two-stage knowledge blocking strategy from shallower to deeper after the provision of hybrid offerings: (1) In the initial stage after provision, manufacturing enterprises let customers grasp the using knowledge of hybrid offerings through co-production and training. Customers desire to obtain deeper knowledge of hybrid offerings, such as accidental fault handling, immediate operation & maintenance and functional repair, to better adapt to market demand fluctuations and reduce delay cost caused by untimely equipment maintenance. At this time, in order to obtain more service opportunities and profit space, manufacturing enterprises usually adopt the first stage of profitable knowledge blocking strategy. (2) As hybrid offerings tend to be homogeneous, it is easier for customers to grasp profitable knowledge. At this stage, customers desire to obtain knowledge about renovation, improvement and overhaul of hybrid offerings, to further expand the value creation scope and break the original use field of hybrid offerings. Therefore, in order to prevent the knowledge diffusion of advantageous businesses, manufacturing enterprises usually adopt the second stage of protective knowledge blocking strategy.Based on the above situation and considering the impact of knowledge sharing on customer utility and knowledge spillover, this paper constructs a model of value creation for supply and demand under three knowledge management strategies (knowledge blocking, profitable knowledge sharing and protective knowledge sharing), aiming to find the boundary of knowledge blocking or sharing. The results show that: (1) The knowledge sharing of hybrid offerings in manufacturing enterprises has a double boundary measured by knowledge spillover cost coefficient. Also, the boundary of protective knowledge sharing is narrower than profitable knowledge sharing. Only by implementing the knowledge sharing strategy within the boundary can manufacturing enterprises realize the value co-creation for supply and demand. (2) The knowledge sharing value creation and the knowledge spillover cost in manufacturing enterprises are in a trade-off relationship. The value creation, optimal price and quantity of hybrid offerings under the protective knowledge sharing are more sensitive to the knowledge spillover coefficient than profitable knowledge sharing. (3) If customers can use shared knowledge to achieve greater value creation, manufacturing enterprises are more willing to share two types of knowledge. Therefore, customers should express their desire for the knowledge and demonstrate their knowledge absorptive capacity to manufacturing enterprises. When the value creation of knowledge sharing becomes predictable and measurable, manufacturing enterprises are more willing to share knowledge with customers under the guidance of a reasonable contract.The conclusions enrich the knowledge management theory in the process of manufacturing servitization and clarify the preconditions for the knowledge sharing contract design. The implications for service-oriented manufacturing enterprises′ knowledge management after the provision of hybrid offerings are: (1) If hybrid offerings dominate the market, manufacturing enterprises can implement the knowledge blocking strategy to ensure a stable revenue stream. (2) If hybrid offerings are highly competitive in the market, manufacturing enterprises can implement the profitable knowledge sharing strategy to stimulate potential customers′ demand. (3) If hybrid offerings tend to be homogeneous, manufacturing enterprises can implement the protective knowledge sharing strategy to stimulate innovative use of hybrid offerings to achieve greater value creation for both supply and demand.

Key words: hybrid offering, knowledge blocking, knowledge sharing, boundary recognition