The authors are carrying out research studies to explore the applicability of knowledge-based systems (KBS) technology to today's competitive plastic product design and development, with an emphasis on the conceptual design stage. The requirement for the application of KBS technology in improving the efficiency and effectiveness of conceptual plastic injection molding part design are discussed. A framework of a knowledge-based evaluation system for new product concepts is proposed in the paper. A prototype knowledge-based system, called EIMPPLAN-1, which can select the appropriate plastic material and generate the major injection mold design features, is also presented. Copyright © 1996 Elsevier Science Ltd.link_to_subscribed_fulltex