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Chen JY, Zhuang JX, Huang MS. Enhancing the quality stability of injection molded parts by adjusting V/P switchover point and holding pressure. POLYMER 2021. [DOI: 10.1016/j.polymer.2020.123332] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Huang MS, Nian SC. Robust parameter search for IC tray injection molding using regrind resin. JOURNAL OF POLYMER ENGINEERING 2020. [DOI: 10.1515/polyeng-2020-0097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Quality consistency is essential in maximizing the productivity rate of the injection molding process and minimizing the production cost. The quality consistency problem is particularly acute in the case of injection molding processes performed using regrind resin, for which the rheological properties are less uniform and more unpredictable than those of virgin material. Accordingly, the present study proposes a two-stage approach for optimizing the injection molding process parameters in such a way as to achieve a consistent molding quality over repeated injection molding cycles. In the first stage, the values of the injection speed/pressure, velocity-to-pressure (V/P) switchover point, and packing pressure are individually determined based on an inspection of the cavity pressure profile and machine parameters provided by the injection molding machine controller. In the second stage, a robust parametric search method based on a first-order regression model is employed to determine the optimal combination of the process parameter settings. Using an Integrated Circuit (IC) tray fabricated from regrind resin for illustration purposes, the results confirm that the proposed method overcomes the problem of small variations in the melt quality and therefore provides an effective technique for improving the yield rate and quality of the continuous mass production.
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Affiliation(s)
- Ming-Shyan Huang
- Department of Mechatronics Engineering , National Kaohsiung University of Science and Technology , 1 University Road , Yanchao Dist. , 824 Kaohsiung City , Taiwan
| | - Shih-Chih Nian
- Department of Power Mechanical Engineering , National Taitung Junior College , 911 Jhengci N. Road , 95045 Taitung , Taiwan
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Grosso G, Troisi EM, Jaensson NO, Peters GW, Anderson PD. Modelling flow induced crystallization of IPP: Multiple crystal phases and morphologies. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.121806] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Quality Indexes Design for Online Monitoring Polymer Injection Molding. ADVANCES IN POLYMER TECHNOLOGY 2019. [DOI: 10.1155/2019/3720127] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Quality control is a crucial issue in the injection molding process with target of obtaining a high yield rate and reducing production cost. Consequently, effective methods for monitoring the injection conditions (e.g., pressure, velocity, and temperature) in real-time and adjusting these conditions adaptively as required to ensure a consistent part quality are essential. This study proposes a quality index based on the clamping force increment during the injection cycle, as determined by four strain gauges attached to the tie bars of the injection molding machine. Also, various quality indexes for online quality monitoring and prediction purposes based on the pressure, viscosity, and energy features extracted from the pressure profiles obtained at the load cell, nozzle, and molding cavity, respectively, are compared. The feasibility of the proposed quality indexes is investigated experimentally for various settings of the barrel temperature, back pressure, and rotational speed of the plasticizing screw. It is shown that all of the quality indexes are correlated with the injection-molded quality and hence provide a feasible basis for the realization of an on-line quality monitoring and control system. Particularly, the tie-bar elongation quality index requires no modification or invasion of the injection molding system or cavity and hence provides a particularly attractive solution for monitoring and controlling the part quality.
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Troisi EM, Caelers HJM, Peters GWM. Full Characterization of Multiphase, Multimorphological Kinetics in Flow-Induced Crystallization of IPP at Elevated Pressure. Macromolecules 2017; 50:3868-3882. [PMID: 28553002 PMCID: PMC5444050 DOI: 10.1021/acs.macromol.7b00595] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/04/2017] [Indexed: 11/29/2022]
Abstract
Understanding the complex crystallization behavior of isotactic polypropylene (iPP) in conditions comparable to those found in polymer processing, where the polymer melt experiences a combination of high shear rates and elevated pressures, is key for modeling and therefore predicting the final structure and properties of iPP products. Coupling a unique experimental setup, capable to apply wall shear rates similar to those experienced during processing and carefully control the pressure before and after flow is imposed, with in situ X-ray scattering and diffraction techniques (SAXS and WAXD) at fast acquisition rates (up to 30 Hz), a well-defined series of short-term flow experiments are carried out using 16 different combinations of wall shear rates (ranging from 110 to 440 s-1) and pressures (100-400 bar). A complete overview on the kinetics of structure development during and after flow is presented. Information about shish formation and growth of α-phase parents lamellae from the shish backbones is extracted from SAXS; the overall apparent crystallinity evolution, amounts of different phases (α, β, and γ), and morphologies developing in the shear layer (parent and daughter lamellae both in α and γ phase) are fully quantified from the analysis of WAXD data. Both flow rate and pressure were found to have a significant influence on the nucleation and the growth process of oriented and isotropic structures. Flow affects shish formation and the growth of α-parents; pressure acts on relaxation times, enhancing the effect of flow, and (mainly) on the growth rate of γ-phase. The remarkably high amount of γ-lamellae found in the oriented layer strongly indicates the nucleation of γ directly from the shish backbone. All the observations were conceptually in agreement with the flow-induced crystallization model framework developed in our group and represent a unique and valuable data set that will be used to further validate and implement our numerical modeling, filling the gap for quantitatively modeling crystallization during complicated processing operations like injection molding.
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Affiliation(s)
- E. M. Troisi
- Department
of Mechanical Engineering, Materials Technology Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Dutch Polymer
Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands
| | - H. J. M. Caelers
- Department
of Mechanical Engineering, Materials Technology Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - G. W. M. Peters
- Department
of Mechanical Engineering, Materials Technology Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Dutch Polymer
Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands
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Zhang L, Van Drongelen M, Alfonso GC, Peters GW. The effect of pressure pulses on isotactic polypropylene crystallization. Eur Polym J 2015. [DOI: 10.1016/j.eurpolymj.2015.07.055] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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van Drongelen M, Gahleitner M, Spoelstra AB, Govaert LE, Peters GWM. Flow-induced solidification of high-impact polypropylene copolymer compositions: Morphological and mechanical effects. J Appl Polym Sci 2015. [DOI: 10.1002/app.42040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Martin van Drongelen
- Department of Mechanical Engineering; Materials Technology Institute; Eindhoven University of Technology; 5600 MB Eindhoven the Netherlands
| | - Markus Gahleitner
- Borealis Polyolefine GmbH; Innovation Headquarters; St. Peterstr. 25 4021 Linz Austria
| | - Anne B. Spoelstra
- Department of Chemical Engineering and Chemistry; Laboratory of Polymer Technology; Eindhoven University of Technology; 5600 MB Eindhoven the Netherlands
| | - Leon E. Govaert
- Department of Mechanical Engineering; Materials Technology Institute; Eindhoven University of Technology; 5600 MB Eindhoven the Netherlands
| | - Gerrit W. M. Peters
- Department of Mechanical Engineering; Materials Technology Institute; Eindhoven University of Technology; 5600 MB Eindhoven the Netherlands
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Forstner R, Peters GWM, Meijer HEH. A Novel Dilatometer for PVT Measurements of Polymers at High Cooling – and Shear Rates. INT POLYM PROC 2013. [DOI: 10.3139/217.2154] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
A novel dilatometer to investigate the specific volume of polymers as a function of the combined effect of pressure (100 MPa), temperature (300°C), cooling rate (100°C/s) and shear rate (200 l/s) was developed. The dilatometer consists of a pressure cell, which in design is a combination of a traditional “piston-die type” dilatometer and a Couette rheometer, embedded in a custom made frame, which allowed for scaling down to a “table-sized” machine that requires only standard laboratory supplies, like pressurized air and tap water, for operation and cooling. We implemented software for fully automated control of procedures to operate non-isothermal experiments with shear steps applied at predefined temperatures. The sample rings (m ≈ 65 mg) used in the dilatometer are made with a micro injection moulding machine. Experiments with two commercial isotactic Polypropylene (iPP) grades at low cooling rates, performed by two independent groups, were compared with measurements from a commercial confined fluids dilatometer showing small relative differences in the range of 0.03 to 0.3%. As an example, additional results of an isotactic polypropylene were chosen to show the profound influence of cooling rate and melt shearing on the evolution of specific volume.
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Affiliation(s)
- R. Forstner
- Eindhoven University of Technology, Faculty of Mechanical Engineering, Section Materials Technology, Eindhoven, The Netherlands
| | - G. W. M. Peters
- Eindhoven University of Technology, Faculty of Mechanical Engineering, Section Materials Technology, Eindhoven, The Netherlands
| | - H. E. H. Meijer
- Eindhoven University of Technology, Faculty of Mechanical Engineering, Section Materials Technology, Eindhoven, The Netherlands
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Housmans JW, Balzano L, Santoro D, Peters GWM, Meijer HEH. A Design to Study Flow Induced Crystallization in a Multipass Rheometer. INT POLYM PROC 2013. [DOI: 10.3139/217.2230] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
The design and performance of a flow geometry for the multipass rheometer (MPR) is described, creating an experimental setup to study in-situ and ex-situ structure and morphology development with a proper control over the processing conditions and shear history. The slit used is equipped with diamond windows, to combine flow with different experimental techniques, such as optical microscopy (OM), birefringence and X-ray scattering. In this paper we present preliminary results, obtained on isotactic polypropylene, that demonstrate the possibilities of this device for more extended future research. The focus is on the in-situ birefringence measurements of crystallization and the relation with the final morphology.
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Affiliation(s)
- J.-W. Housmans
- Materials Technology, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - L. Balzano
- Materials Technology, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - D. Santoro
- Department of Chemical and Food Engineering University of Salerno, Italy
| | - G. W. M. Peters
- Materials Technology, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - H. E. H. Meijer
- Materials Technology, Eindhoven University of Technology, Eindhoven, The Netherlands
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van Drongelen M, van Erp T, Peters G. Quantification of non-isothermal, multi-phase crystallization of isotactic polypropylene: The influence of cooling rate and pressure. POLYMER 2012. [DOI: 10.1016/j.polymer.2012.08.003] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Random and block copolymers based on 4-methyl-1-pentene and 1-pentene. POLYMER 2012. [DOI: 10.1016/j.polymer.2012.05.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Wang J, Xie P, Yang W, Ding Y. Online pressure-volume-temperature measurements of polypropylene using a testing mold to simulate the injection-molding process. J Appl Polym Sci 2010. [DOI: 10.1002/app.32070] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Housmans JW, Gahleitner M, Peters GW, Meijer HE. Structure–property relations in molded, nucleated isotactic polypropylene. POLYMER 2009. [DOI: 10.1016/j.polymer.2009.02.050] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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