A clear and well-defined new product development (NPD) process, cross-functional development teams and project fit with manufacturing resources and skills, are three areas critical to achieve lower cost, high quality and short time to market in NPD. However it is not clear who from manufacturing function should be involved and in which phase during the NPD project. In order to address this issue, the purpose of this paper is to identify how and when manufacturing functions such as engineers and operators are involved in a NPD project. Results from a conducted case study in heavy automotive component assembly show that manufacturing engineers have been more actively involved compared to manufacturing operators during the early phases of the studies NPD. It confirms earlier results that it is not easy to involve operators in the early phases of project due to abstraction and ambiguity associated with early design.