Title: Optimum ejector system design for plastic injection moulds

Authors: Z. Wang, K.S Lee, J.Y.H Fuh, Z. Li, Y.F. Zhang, A.Y.C. Nee, D.C.H. Yang

Addresses: Department of Mechanical and Production Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore. ' Department of Mechanical and Production Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore. ' Department of Mechanical and Production Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore. ' Department of Mechanical and Production Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore. ' Department of Mechanical and Production Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore. ' Department of Mechanical and Production Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore. ' National University of Singapore, 10 Kent Ridge Crescent, Singapore; Department of Mechanical & Aerospace Engineering, University of California at Los Angels (UCLA), USA

Abstract: Injection moulding is a technology predominantly used for processing thermoplastic polymers. The injection moulding cycle for thermoplastics consists of several major stages. At the end of the injection cycle the plastic moulded part has to be ejected when the injection mould opens. Since the ejection force from the ejector plate is usually great enough for the required releasing force, mould designers usually neglect the balance of the ejection force which is exerted on the sticking surface. Part deformation or damage might occur due to the unbalance of the ejection force. This paper describes an efficient algorithm for optimizing the arrangement and selection of ejectors. The required releasing/ejection force should be proportional to the area of the sticking surface. Furthermore, a CAD environment has been developed to facilitate the ejector system design. The processes for optimisation and implementation of the algorithm are described in detail and a case study is presented to illustrate the procedure.

Keywords: ejector systems; ejection force; injection moulding; part ejection; releasing force; sticking force; thermoplastic polymers; computer-aided design; CAD; mould design.

DOI: 10.1504/IJCAT.1996.062312

International Journal of Computer Applications in Technology, 1996 Vol.9 No.4, pp.211 - 218

Published online: 03 Jun 2014 *

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