Numerical Simulation of Polymer Melt Flow Control for a Multi-Cavity Mold During Injection Molding Processes

2003 ◽  
Author(s):  
Ahmet Pinarbasi ◽  
Gregory S. Layser ◽  
John P. Coulter
Keyword(s):  
Numerical Simulation ◽  
Injection Molding ◽  
Flow Control ◽  
Polymer Melt ◽  
Volumetric Flow Rate ◽  
Melt Flow ◽  
Valve System ◽  
Control Concept ◽  
Flow Through ◽  
Plastic Parts

Process control is an important factor for improving the performance and consistency of thermoplastic parts manufactured by injection molding processes. A critical process parameter for manufacturing of high quality plastic parts is cavity pressure. This paper presents direct numerical simulation results of a new manufacturing concept developed to improve injection molding processing for all runner types by monitoring shot to shot product quality and controlling the filling of multi-cavity molds in real time. A cold runner system supplying polymer melt to a two-cavity mold incorporating mechanical valves in the runner systems was modeled. Each valve was controlled independently to meter flow and pressure to its portion of the mold. Simulations were performed for two different materials: PPS Ryton R-4-200 and LCP Vectra E130D-2. Shear-rate dependence of viscosity of the materials is modeled through the Cross rheological equation. Flow rates and maximum shear-rates through valves were calculated and the results of the simulations were analyzed to validate the concept of individual cavity filling modification. Flow through one valve system leading to a single cavity was simulated first, followed by flow through two-valve system for filling two cavities. For one valve simulations, pressure at the inlet was specified, whereas for flow through two-valve system, volumetric flow rate at the inlet was supplied for simulations. It was concluded that the flow control concept developed was numerically validated, and it was shown that the valve system proposed here is applicable to control melt flow through cavities at industrial manufacturing facilities. The future directions for the continuing project are also discussed.

Numerical Simulation in a Multiple Flow Control Valve System of Polymer Melt During Injection Molding Processes

2005 ◽  
Author(s):  
Gregory S. Layser ◽  
John P. Coulter
Keyword(s):  
Injection Molding ◽  
Flow Control ◽  
Current System ◽  
Control Valve ◽  
Polymer Melt ◽  
Flow Control Valve ◽  
Flow Modulation ◽  
Valve System ◽  
Plastic Parts ◽  
Critical Process

Process control is an important factor for improving the performance and consistency of thermoplastic parts manufactured by injection molding processes. A critical process parameter for manufacturing of high quality plastic parts is cavity pressure. This paper presents a continuation of a numerical based study of flow control utilized during multi-cavity injection molding processes and focuses in more detail on multiple flow control valve systems, since the valves are coupled with one injection source. The capabilities of the current system design are limited by multiple valve interactions, which may produce undesirable effects in regards to flow modulation and pressure distribution in multiple cavities and should be studied further. Understanding the flow modeling details through a single valve system is essential, thereby reducing the computational work involved with a multiple valve system.

The Utilization of Flow Control During Multi-Cavity Injection Molding Processes

Materials ◽  
2004 ◽  
Author(s):  
Gregory S. Layser ◽  
John P. Coulter ◽  
Gregory M. Bielawiec
Keyword(s):  
Injection Molding ◽  
Flow Control ◽  
Flow Rate ◽  
Control Valve ◽  
Polymer Melt ◽  
Processing Parameters ◽  
Industrial Manufacturing ◽  
Mechanical Valves ◽  
Control Concept ◽  
Plastic Parts

Process control is an important factor for improving the performance and consistency of thermoplastic parts manufactured by injection molding processes. A critical process parameter for manufacturing of high quality plastic parts is cavity pressure. This paper presents a continuation of a numerical based study of the utilization of flow control specifically for cold runner applications in multi-cavity injection molding processes. A cold runner system supplying polymer melt to a multi-cavity mold incorporating several types of mechanical valves in the runner systems was modeled and manufactured. Each valve independently controls the flow and pressure to its portion of the mold. The goal of the numerical simulation phase of the present investigation was to numerically simulate and thus validate a physical capability to modify the filling of individual cavities during injection molding of products utilizing multi-cavity tooling. A decision was made to attempt to do so by physically controlling the flow rate of polymer into each cavity. The tooling set was made adaptive through the incorporation of custom designed control valves into the runner channels leading to each product cavity. Simulations of both the overall adaptive tooling concept and the specific control valve designs were performed with LCP and PPS as a molding material. It was concluded that the flow control concept developed was numerically validated [1–3], and it was shown that the valve system proposed here is applicable to control melt flow through cavities at industrial manufacturing facilities. The adaptive tooling developed and simulated during the current investigation yielded significant variations in both processing parameters and resultant product quality in response to in-tooling control valve adjustments. It was found that by changing valve angle settings, the flow rate to each cavity could be controlled individually without degrading desired material properties. In an attempt to further promote the flow control concept, an experimental mold was developed and forms the basis for this paper. Preliminary experimental results verifying previous work and the future directions for the continuing project are also discussed.

Polymer Melt Flow through Channels with Vibrating Walls

2002 ◽  
Vol 230-232 ◽  
pp. 300-302 ◽  
Author(s):  
M. Martins ◽  
José A. Covas
Keyword(s):  
Polymer Melt ◽  
Melt Flow ◽  
Flow Through

Observation of Polypropylene (PP) Melt Flow on Macro and Micro Cavities during Filling Phase of Injection Molding

2011 ◽  
Vol 314-316 ◽  
pp. 1273-1277
Author(s):  
M. Azuddin ◽  
Z Taha ◽  
Imtiaz Ahmed Choudhury
Keyword(s):  
Injection Molding ◽  
High Speed ◽  
Electrical Discharge Machining ◽  
Mold Cavity ◽  
Melt Flow ◽  
Observation Window ◽  
Custom Made ◽  
Micro Parts ◽  
Filling Phase ◽  
Plastic Parts

The flow of plastic melt in macro and micro parts during the filling phase of injection molding is an interesting area to discover. The visualization technique is a common method used to understand the phenomena of polymer flow in mold cavity. Various shapes and sizes were fabricated on aluminum molds embedded with Polymethyl Methacrylate (PMMA) as observation window. Electrical discharge machining (EDM) and micro mechanical machining method were employed to fabricate plastic parts shape on aluminum mold cavity. This paper focuses and discusses in detail on the Polypropylene (PP) melt flow injected using a custom made vertical injection molding machine. The PP melt flow can be clearly seen through the PMMA window and captured using high speed camera. The captured images are then compared with result from commercially available plastic injection molding software, Autodesk MoldFlow. It was found that there is good agreement for macro plastic parts but not for the micro parts. It can be concluded that, the analysis software has less capability in predicting the flow of melt plastic in micro parts.

scholarly journals Numerical Analysis for Polymer Melt Flow in Injection Molding.

1994 ◽  
Vol 37 (3) ◽  
pp. 531-537 ◽  
Author(s):  
Katsuhiko Sagae ◽  
Makoto Koizumi ◽  
Masanori Yamakawa
Keyword(s):  
Numerical Analysis ◽  
Injection Molding ◽  
Polymer Melt ◽  
Melt Flow

Conjugate transport in polymer melt flow through extrusion dies

1997 ◽  
Vol 37 (9) ◽  
pp. 1582-1595 ◽  
Author(s):  
P. Lin ◽  
Y. Jaluria
Keyword(s):  
Polymer Melt ◽  
Melt Flow ◽  
Extrusion Dies ◽  
Flow Through

scholarly journals NUMERICAL INVESTIGATION OF THE POLYMER MELT FLOW IN INJECTION MOLDING BY USING ILU PRECONDITIONED GMRES

1999 ◽  
Vol 4 (1) ◽  
pp. 174-184
Author(s):  
U. Türk ◽  
A. Ecder
Keyword(s):  
Linear System ◽  
Injection Molding ◽  
Krylov Subspace ◽  
Polymer Melt ◽  
Computational Domain ◽  
Melt Flow ◽  
Polymer Flow ◽  
Non Linear ◽  
Energy Equations ◽  
Non Linear System

The implementation of a modern preconditioned Newton‐Krylov solvers to the polymer melt flow in injection molding is the main focus of this paper. The viscoelastic and non‐isothermal characteristics of the transient polymer flow is simulated numerically and the highly non‐linear problem solved. This non‐linear behavior results from the combination of the dominant convective terms and the dependence of the polymer viscosity to the changing temperature and the shear rate. The governing non‐Newtonian fluid flow and energy equations with appropriate approximations are discretized by finite differencing. Elliptic Grid Generation technique is used to map physical domain to computational domain. The resulting non‐linear system is solved by using Newton's method. GMRES, one of the Krylov subspace methods, used as an iterative algorithm in order to solve the linear system at each non‐linear step. Incomplete LU preconditioner is used for better convergence. Numerical solution of polymer flow is presented to demonstrate that these methods are efficient and robust for solving such flow problems.

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