This paper presents a new A3 thinking approach of problem solving to support the Lean Product and Process Development (LeanPPD) in knowledge-based environment. The new approach allows the design team to obtain the scientific knowledge in a structured manner. It also enables them to understand the linkage between hypothesis and practice which results from the new understanding and could be considered as new learning. This knowledge will support the designers in effective decision making whilst directly attacking the waste during the next of the product development phases and future projects surrounded by the knowledge rich environment. The industrial field study has carried out among thirty six designers and engineers in European manufacturing companies. The best practices of problem solving approaches and mechanism and challenges of knowledge capture have been collected. Therefore, the A3 thinking approach is proposed to be developed that stemmed to the industries requirements.