Towards Controllability of Injection Molding

1999 ◽  
Author(s):  
David Kazmer ◽  
David Hatch
Keyword(s):  
Injection Molding ◽  
System Design ◽  
Polymer Melt ◽  
Thermal Control ◽  
Polymer Processing ◽  
Injection Molding Process ◽  
Molding Process ◽  
Thermal Dynamics ◽  
Design Changes ◽  
Novel Processing

Abstract Process control has been recognized as an important means of improving the performance and consistency of thermoplastic parts. However, no single control strategy or system design has been universally accepted, and molding systems continue to produce defective components during production. The capability of the injection molding process is limited by the thermal and flow dynamics of the heated polymer melt. This paper discusses some of the difficulties posed by complex and distributed nature of the injection molding process. The flow and thermal dynamics of the process are analyzed with respect to transport and rheology. Then, two novel processing methods are described to enable in-cycle flow, pressure, and thermal control. Simulation and experimental results demonstrate effectiveness of these innovations to increase the consistency and flexibility in polymer processing. Such system design changes simplify the requisite control structures while improving the process robustness and productivity.

Comprehensive Online Control Strategies for Plastic Injection Molding Process

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Jaho Seo ◽  
Amir Khajepour ◽  
Jan P. Huissoon
Keyword(s):  
Injection Molding ◽  
Injection Pressure ◽  
Thermal Control ◽  
Plastic Injection Molding ◽  
Injection Molding Process ◽  
Molding Process ◽  
Element Analysis ◽  
Thermal Dynamics ◽  
Uncertain Dynamics ◽  
Plastic Injection

This study proposes an effective thermal control for plastic injection molding (polymer: Santoprene 8211-45 with density of 790 kg/m3, injection pressure: 1400 psi (9,652,660 Pa)) in a laminated die. For this purpose, a comprehensive control strategy is provided to cover various themes. First, a new method for determining the optimal sensor locations as a prerequisite step for modeling and controller design is introduced. Second, system identification through offline and online training with finite element analysis and neural network techniques are used to develop an accurate model by incorporating uncertain dynamics of the laminated die. Third, an additive feedforward control by adding direct adaptive inverse control to self-adaptive PID is developed for temperature control of cavity wall (cavity size: 52.9 × 32.07 × 16.03 mm). A verification of designed controller's performance demonstrates that the proposed strategy provides accurate online temperature tracking and faster response under thermal dynamics with various cycle-times in the injection mold process.

Evaluation of a Piezoelectric Energy Extraction Device for Cavity Pressure Sensing in Injection Molding

2003 ◽  
Author(s):  
Charles B. Theurer ◽  
Li Zhang ◽  
David Kazmer ◽  
Robert X. Gao
Keyword(s):  
Injection Molding ◽  
Mechanical Strain ◽  
Piezoelectric Element ◽  
Polymer Melt ◽  
High Energy ◽  
Injection Molding Process ◽  
Molding Process ◽  
Transient Model ◽  
Piezoelectric Energy ◽  
Wide Range

This paper presents the design, analysis, and validation of a self-energized piezoelectric pressure sensor that extracts energy from the pressure differential of the polymer melt during the injection molding process. To enable a self-energized sensor design, an analytical study has been conducted to establish a quantitative relationship between the polymer melt pressure and the energy that can be extracted through a piezoelectric converter. Temperature and pressure are monitored during an injection molding cycle and the performance of the piezoelectric element is evaluated with respect to a mechanically static, electrically transient model. In addition to corroboration of the proposed model, valuable statistical information about the working temperature in the prototype sensor will prove very useful in the package design of molding cavity sensors. A linear model examining the energy conversion mechanism due to interactions between the mechanical strain and the electric field developed within the piezoelectric device is established. This model is compared to the functional prototype design to evaluate the relevance of the assumptions and accuracy. The presented design enables a new generation of self-energized sensors that can be employed for the condition monitoring of a wide range of high-energy manufacturing processes.

Influence of Technological Parameters on Material Flow

2015 ◽  
Vol 1120-1121 ◽  
pp. 1194-1197 ◽  
Author(s):  
Michal Stanek ◽  
David Manas ◽  
Miroslav Manas ◽  
Vojtech Senkerik ◽  
Adam Skrobak ◽  
...  
Keyword(s):  
Injection Molding ◽  
Injection Pressure ◽  
Polymer Processing ◽  
Injection Rate ◽  
Cavity Surface ◽  
Injection Molding Process ◽  
Technological Parameters ◽  
Molding Process ◽  
Processing Technologies

Injection molding is one of the most extended polymer processing technologies. It enables the manufacture of final products, which do not require any further operations. The tools used for their production – the injection molds – are very complicated assemblies that are made using several technologies and materials. Delivery of polymer melts into the mold cavity is the most important stage of the injection molding process. The fluidity of polymers is affected by many parameters Inc. mold design. Evaluation of set of data obtained by experiments in which the testing conditions were widely changed shows that the quality of cavity surface and technological parameters (injection rate, injection pressure and gate size) has substantial influence on the length of flow.

scholarly journals Evaluation by nanoindentation of technological products manufactured by pulse injection molding process

2018 ◽  
Vol 145 ◽  
pp. 02006
Author(s):  
Margarita Natova ◽  
Ivan Ivanov ◽  
Sabina Cherneva ◽  
Maria Datcheva ◽  
Roumen Iankov
Keyword(s):  
Injection Molding ◽  
Polymer Melt ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Molding Process ◽  
Polymer Injection ◽  
Pulse Injection ◽  
Molding Flow ◽  
Different Parts ◽  
Technological Products

During conventional polymer injection molding, flow- and weld lines can arise at the molded parts caused by disturbed polymer melt flow when it crosses different parts of the equipment. Such processed plastic goods have discrete zones of inhomogeneities of very small dimensions. In order to stabilize the melt flow and to equalize dimensions of such defective products, an approach for pulse injection molding is applied during production of polymer packagings. Testing methods used for evaluation of macromechanical performance of processed polymer products are not readily applicable to estimate the changes in visual surface obtained during pulse injecting. To overcome this testing inconvenience the performance of processed packagings is evaluated by nanoindentation. Using this method, a quantitative assessment of the polymer properties is obtained from different parts of technological products.

An Investigation into the Influencing Factors for Polymer Melt at the Filling Stage in Micro Injection Molding

2013 ◽  
Vol 562-565 ◽  
pp. 1380-1386
Author(s):  
Jian Zhuang ◽  
Da Ming Wu ◽  
Ya Jun Zhang ◽  
Lin Wang ◽  
Xiong Wei Wang ◽  
...  
Keyword(s):  
Injection Molding ◽  
Influencing Factors ◽  
Polymer Melt ◽  
Theoretical Models ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Molding Process ◽  
Micro Injection Molding ◽  
Filling Stage ◽  
Conventional Injection Molding

The flow behaviors for polymer melt at the filling stage in micro injection molding are different from those in conventional injection molding due to the miniaturization of plastic parts. This paper focuses on the study of the effects of three main influencing factors, including the microscale viscosity and wall slip, on melt filling flow in microscale neglected those in conventional injection molding process. The theoretical models and the interrelation of these factors in microscale channels were constructed by means of the model correction method. Then, the micro melt flow behaviors were investigated with comparisons of the available experimental data. The results indicate that the dimensions affect the shear rates and viscous dissipation, which in turn affects the apparent viscosity. Finally, the conclusion is that the melt flow behaviors in microchannels are different from those in macrochannels owing to these significant influencing factors.

Viscosity Measurement in Injection Molding Using a Multivariate Sensor

2012 ◽  
Author(s):  
N. Asadizanjani ◽  
R. X. Gao ◽  
Z. Fan ◽  
D. O. Kazmer
Keyword(s):  
Injection Molding ◽  
Polymer Melt ◽  
Experimental Tests ◽  
Injection Molding Process ◽  
Online Measurement ◽  
Cavity Pressure ◽  
Molding Process ◽  
Ir Detector ◽  
Melt Temperature

Online measurement of polymer melt properties during an injection molding process is a key to provide a high quality plastic product. In-situ cavity pressure and temperature sensors are used to observe the polymer states in the mold cavity during an injecting molding process. A new multivariate sensor is introduced to measure pressure, temperature, velocity, and viscosity of polymer melt as the key parameters of the melt to improve the controlling process. This paper presents the viscosity calculating method based on melt velocity and the slope of melt pressure. The velocity is inferred using the melt temperature ramping rate; the new multivariate sensor detects melt temperature through the installed IR detector in the sensor, and the pressure is measured via the mounted piezoelectric rings. Injecting molding process of polymer melt is simulated under a range of melt velocity and temperature and the related viscosity values are inferred from simulation results and also from a set of experimental tests for a real injection molding process. Results are well matched with the expected rheological behavior of polymer.

Study of polymer melt flow in sequential injection molding process

AIChE Journal ◽  
1996 ◽  
Vol 42 (6) ◽  
pp. 1706-1714 ◽  
Author(s):  
S. C. Chen ◽  
N. T. Chen ◽  
K. S. Hsu ◽  
K. F. Hsu
Keyword(s):  
Injection Molding ◽  
Polymer Melt ◽  
Injection Molding Process ◽  
Sequential Injection ◽  
Melt Flow ◽  
Molding Process
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