Interfaces between technology development, product development, and production must be managed in order to avoid misfits between technology and product concepts and ensure the fit of the product design and the production process. In this paper, critical challenges related to these interfaces are studied based on in-depth case studies of ten product development projects at five manufacturing firms, two workshops and a questionnaire. Our findings indicate that factors related to synchronisation and transfer management are most critical. A tentative model is formulated as an instrument to reduce risk and uncertainty related to the interfaces.