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Computer‐aided optimal melt screw design
Author(s) -
Helmy H. A. A.,
Parnaby J.
Publication year - 1976
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760160609
Subject(s) - plastics extrusion , mechanical engineering , computer science , process (computing) , optimal design , set (abstract data type) , flow (mathematics) , computer aided design , engineering drawing , materials science , engineering , mathematics , geometry , machine learning , composite material , programming language , operating system
The paper describes a computer software package applying a steady‐state hill‐climbing optimization routine to the plastics melt‐extruder screw constrained‐design problem. The purpose primarily is to introduce the optimal screw‐design technique, to show how it is applied to this particular type of problem, to indicate its potential and to encourage its wider use. Screw performance criteria are defined by a theoretical model consisting of the non‐Newtonian isothermal polymer flow equations in terms of the screw‐geometric variables for particular process conditions. The design method is quite general however and a non‐isothermal model may be substituted. Use of the method offers considerable scope and potential for the design engineer to make design processes faster, more positive and logical while reducing the effort required. Interactive use is possible and empirical adjustments can be incorporated with experience. In using the method, the design engineer first specifies the required process conditions of pressure and flow rate at the die and the computer then searches for the set of screw design variables which optimizes the screw power utilization efficiency or any other specified criterion of performance. Such optimal designs are obtained within the set limits of practical constraints on machine dimensions, screw strength and product quality requirements. Some experimental evidence is given relating to the accuracy of the isothermal non‐Newtonian polymer flow model and to its use in the design of small diameter extruder screws. The optimal search technique offers considerable potential as a computer‐based design tool.