A Knowledge-Based Engineering System for the Design of Injection Molded Plastic Parts

1993 ◽  
Author(s):  
S. D. Pratt ◽  
M. Sivakumar ◽  
S. Manoochehri
Keyword(s):  
Data Entry ◽  
Engineering System ◽  
Hybrid Features ◽  
Object Oriented Design ◽  
Knowledge Based ◽  
Injection Molded ◽  
Knowledge Based Engineering ◽  
Product And Process ◽  
Plastic Parts ◽  
Injection Molded Plastic

Abstract This study presents a knowledge-based engineering system for the design of injection molded plastic parts which is built around a commercial object-oriented design language. Knowledge-based engineering is an implementation paradigm in which the knowledge about the part is stored along with its geometry and the knowledge is used to verify the manufacturability and processability of the part. This system enables the designer to represent the plastic part in terms of hybrid features which associate product and process knowledge with part geometry. Engineering rules about part moldability and strength, process and material considerations, and mold design are captured in the system. To illustrate the capability and application of the system to real-world problems, the design of an enclosure for a portable data entry device is pursued. This exercise demonstrates the effectiveness and robustness of the system which applied appropriate rules at different stages of design to make the part inherently moldable.

scholarly journals Use of Knowledge-Based Engineering in Compressor Rotor Design

1995 ◽  
Author(s):  
John Marra
Keyword(s):  
Design Process ◽  
Concurrent Engineering ◽  
Synergistic Effects ◽  
General Description ◽  
Knowledge Based ◽  
Compressor Rotor ◽  
Product And Process Knowledge ◽  
Knowledge Based Engineering ◽  
Product And Process ◽  
Use Of Knowledge

Competitive pressures are forcing manufacturers of turbine engines to reduce product development times, minimize design iterations, and react rapidly to changing markets and customers. Concurrent Engineering replaces the traditional sequential design process with parallel efforts in multiple disciplines, increasing product quality while reducing leadtime. Knowledge-Based Engineering captures product and process knowledge contained in the “corporate memory” to enhance and accelerate the design process. Linking the two together provides a wide variety of synergistic effects not separately available. In this paper a general description of the process used to create a Knowledge Based Engineering (KBE) System capable of Concurrent Engineering (CE) will be presented, along with selected results. The summary discusses use of the system created to pursue real world design problems.

Dimensional Tolerancing and Control in Molded Products

2003 ◽  
Author(s):  
David Kazmer ◽  
Kaushik Manek ◽  
Cybele Lotti ◽  
Rosario E. S. Bretas ◽  
Liang Zhu
Keyword(s):  
Six Sigma ◽  
Capability Indices ◽  
Tolerance Specification ◽  
Mean And Variance ◽  
Injection Molded ◽  
Product And Process ◽  
Standard Practices ◽  
Injection Molded Plastic ◽  
And Control ◽  
Better Than

Design and manufacturing of engineered products are subject to uncontrolled variation (noise) and unknown performance behavior and/or requirements (uncertainty). Skilled practitioners currently utilize robust design and Six Sigma techniques for tolerance specification and parametric optimization to control the mean and variance of the performance characteristics. Even after several design iterations, however, the final product and process design may not be optimal and result in unacceptable performance or quality levels. This paper explores the validity of current Six Sigma practices for dimensional tolerancing and process optimization in the manufacturing of an injection molded plastic part. Specifically, the use of process capability indices and aggregate performance measures are discussed relative to the shrinkage behavior of isotactic polypropylene, i-PP. The results indicate that uncertainty and covariance between multiple part dimensions can invalidate standard practices. While current best practices may be better than completely unstructured approaches, the resulting product and process designs provide suboptimal product characteristics, broad performance distributions, and low manufacturing yields.

Design for Injection Molding: Using Dimensional Analysis to Assess Fillability

1994 ◽  
Author(s):  
Douglas C. Mehl ◽  
Kurt A. Beiter ◽  
Kos Ishii
Keyword(s):  
Dimensional Analysis ◽  
Process Simulation ◽  
Design Guidelines ◽  
Experimental Program ◽  
Flow Length ◽  
Numerical Process ◽  
Injection Molded ◽  
Plastic Parts ◽  
Injection Molded Plastic

Abstract This paper addresses the determination of wall thicknesses and gating schemes in the preliminary design of injection-molded plastic parts. Today, most of the existing design guidelines come in the form of experience-based qualitative rules. If the designers already have a detailed geometry of the part, the numerical process simulation program provides another form of design aid. There exists a huge gap between these two types of design aids; the experience-based guidelines are often too vague, while the process simulation programs come too late to impact preliminary part design. To fill this gap, this paper develops physics-based guidelines that utilize dimensional analysis techniques. Experiments and simulation studies can deduce non-dimensional relationships between flow length, thickness, material, and process parameters. The guidelines will aid plastic component designers in determining wall-thickness, gating schemes, and in selecting the material in the preliminary stages of part design. This paper describes the formulation of the non-dimensional charts for fillability assessment, and explains the use of these charts in part design. We further outline an ongoing experimental program to validate and refine our formulation.

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