Residual stresses in polymers III: The influence of injection-molding process conditions

1982 ◽  
Vol 22 (9) ◽  
pp. 560-568 ◽  
Author(s):  
A. Siegmann ◽  
A. Buchman ◽  
S. Kenig
Keyword(s):  
Injection Molding ◽  
Residual Stresses ◽  
Injection Molding Process ◽  
Process Conditions ◽  
Molding Process

scholarly journals Experimental Validation of Injection Molding Simulations of 3D Microparts and Microstructured Components Using Virtual Design of Experiments and Multi-Scale Modeling

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 614 ◽  
Author(s):  
Dario Loaldi ◽  
Francesco Regi ◽  
Federico Baruffi ◽  
Matteo Calaon ◽  
Danilo Quagliotti ◽  
...  
Keyword(s):  
Injection Molding ◽  
Process Simulation ◽  
Current Work ◽  
Injection Molding Process ◽  
Process Conditions ◽  
Virtual Design ◽  
Molding Process ◽  
Micro Injection Molding ◽  
Multi Scale ◽  
Filling Time

The increasing demand for micro-injection molding process technology and the corresponding micro-molded products have materialized in the need for models and simulation capabilities for the establishment of a digital twin of the manufacturing process. The opportunities enabled by the correct process simulation include the possibility of forecasting the part quality and finding optimal process conditions for a given product. The present work displays further use of micro-injection molding process simulation for the prediction of feature dimensions and its optimization and microfeature replication behavior due to geometrical boundary effects. The current work focused on the micro-injection molding of three-dimensional microparts and of single components featuring microstructures. First, two virtual a studies were performed to predict the outer diameter of a micro-ring within an accuracy of 10 µm and the flash formation on a micro-component with mass a 0.1 mg. In the second part of the study, the influence of microstructure orientation on the filling time of a microcavity design section was investigated for a component featuring micro grooves with a 15 µm nominal height. Multiscale meshing was employed to model the replication of microfeatures in a range of 17–346 µm in a Fresnel lens product, allowing the prediction of the replication behavior of a microfeature at 91% accuracy. The simulations were performed using 3D modeling and generalized Navier–Stokes equations using a single multi-scale simulation approach. The current work shows the current potential and limitations in the use of micro-injection molding process simulations for the optimization of micro 3D-part and microstructured components.

Experimental determination of friction coefficients between thermoplastics and rapid tooled injection mold materials

2005 ◽  
Vol 11 (3) ◽  
pp. 167-173 ◽  
Author(s):  
Mary E. Kinsella ◽  
Blaine Lilly ◽  
Benjamin E. Gardner ◽  
Nick J. Jacobs
Keyword(s):  
Injection Molding ◽  
Accurate Determination ◽  
Rapid Tooling ◽  
Injection Molding Process ◽  
Process Conditions ◽  
Molding Process ◽  
Friction Coefficients ◽  
Content Type ◽  
Temperature Conditions

PurposeTo determine static friction coefficients between rapid tooled materials and thermoplastic materials to better understand ejection force requirements for the injection molding process using rapid‐tooled mold inserts.Design/methodology/approachStatic coefficients of friction were determined for semi‐crystalline high‐density polyethylene (HDPE) and amorphous high‐impact polystyrene (HIPS) against two rapid tooling materials, sintered steel with bronze (LaserForm ST‐100) and stereolithography resin (SL5170), and against P‐20 mold steel. Friction tests, using the ASTM D 1894 standard, were run for all material pairs at room temperature, at typical part ejection temperatures, and at ejection temperatures preceded by processing temperatures. The tests at high temperature were designed to simulate injection molding process conditions.FindingsThe friction coefficients for HDPE were similar on P‐20 Steel, LaserForm ST‐100, and SL5170 Resin at all temperature conditions. The HIPS coefficients, however, varied significantly among tooling materials in heated tests. Both polymers showed highest coefficients on SL5170 Resin at all temperature conditions. Friction coefficients were especially high for HIPS on the SL5170 Resin tooling material.Research limitations/implicationsApplications of these findings must consider that elevated temperature tests more closely simulated the injection‐molding environment, but did not exactly duplicate it.Practical implicationsThe data obtained from these tests allow for more accurate determination of friction conditions and ejection forces, which can improve future design of injection molds using rapid tooling technologies.Originality/valueThis work provides previously unavailable friction data for two common thermoplastics against two rapid tooling materials and one steel tooling material, and under conditions that more closely simulate the injection‐molding environment.

Design of Optimization Parameters with Hybrid Genetic Algorithm Method in Multi-Cavity Injection Molding Process

2012 ◽  
Vol 463-464 ◽  
pp. 587-591 ◽  
Author(s):  
Wen Jong Chen ◽  
Jia Ru Lin
Keyword(s):  
Genetic Algorithm ◽  
Injection Molding ◽  
Hybrid Genetic Algorithm ◽  
Injection Molding Process ◽  
Process Conditions ◽  
Molding Process ◽  
Optimization Parameters ◽  
Genetic Algorithm Method ◽  
Artificial Neural Network Ann ◽  
Cae Simulation

This paper combines an artificial neural network (ANN) with a traditional genetic algorithm (GA) method, called hybrid genetic algorithm (HGA), to analyze the warpage of multi-cavity plastic injection molding parts. Simulation results indicate that the minimum and the maximum warpage of the hybrid genetic algorithm (HGA) method were lower than that of the traditional GA method and CAE simulation. These results reveal that, when HGA is applied to multi-cavity plastic warpage analysis, the optimal process conditions are significantly better than those using the traditional GA method or CAE simulation.

scholarly journals Effects of Injection Molding Process Conditions on Physical Properties of EPDM Using Design of Experiment Method

2018 ◽  
Vol 167 ◽  
pp. 02016 ◽  
Author(s):  
Young Shin Kim ◽  
Euy Sik Jeon ◽  
Eui Seob Hwang
Keyword(s):  
Injection Molding ◽  
Physical Properties ◽  
Raw Material ◽  
Injection Molding Process ◽  
Process Conditions ◽  
Process Variables ◽  
Molding Process ◽  
Test Pieces ◽  
Experiment Method ◽  
Major Factors

The process variables such as time and temperature during the EPDM-injection molding not only change the physical properties of the raw material but also affect the insertion and separations forces when a grommet product is molded and mounted on a car body. Using the design of experiments method, the major factors in the injection molding process were considered to analyze their effects on the physical properties of the obtained EPDM materials. Test pieces were prepared under different process conditions, tensile strength and elongation were measured, and their correlation was analyzed.

scholarly journals Stress Whitening as an Observation Method of Residual Stress in MABS Polymer Material through the Example of Holding Pressure in an Injection Molding Process

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2871
Author(s):  
Paweł Brzęk ◽  
Tomasz Sterzyński
Keyword(s):  
Residual Stress ◽  
Injection Molding ◽  
Residual Stresses ◽  
Local Stress ◽  
Acrylonitrile Butadiene Styrene ◽  
Processing Parameters ◽  
Injection Molding Process ◽  
Molding Process ◽  
Optical Visualization ◽  
Stress Whitening

The effects such as warpage, dimensional instability and environmental stress corrosion, due to the presence of residual stresses in polymeric products, are strongly dependent on injection molding conditions. The holding time and holding pressure belongs to most important processing parameters, determining the dimensional stability and properties of injected goods. A new procedure based on a visualization technique was applied, where the levels of residual stresses of the samples were estimated. The experiments were performed for samples produced of translucent methacrylate acrylonitrile butadiene styrene (MABS), a commodity polymer with a high transparency, necessary for the optical visualization of the stress whitening. The samples produced by injecting molding were deformed to a constant elongation, to observe the dependent stress whitening effect subsequently used to evaluate the stress distribution. It was found that depending on the value of the injection holding pressure, various levels of residual stress and its distribution may be observed in MABS samples. These measurements conformed that the applied optical method is an easy-to-perform technique. The possibility to detect the residual stresses over the whole cross-section of the transparent product, without the necessity for local stress determination, is another significant advantage of this investigation procedure.

Influence of Injection Molding Parameters on the Consistency of Molding Process

2013 ◽  
Vol 446-447 ◽  
pp. 398-402
Author(s):  
S. Azmoudeh ◽  
H. Zamani ◽  
K. Shelesh-Nezhad
Keyword(s):  
Injection Molding ◽  
Signal To Noise Ratio ◽  
Injection Molding Process ◽  
Process Conditions ◽  
Cavity Pressure ◽  
Molding Process ◽  
Injection Speed ◽  
Taguchi Design Of Experiments ◽  
Pressure Profiles ◽  
Molded Parts

The existence of variations in the injection molding process conditions leads to the inconsistency of molded parts quality during the molding cycles. In this research, the variations of cavity pressure-time profiles integrals over the molding cycles were accounted as the molded parts quality variations. Thereafter, the correlations between injection molding process settings and the degree of consistency of molding process were investigated by applying cavity pressure measurement, Taguchi design of experiments approach and signal to noise ratio. The results derived from experiments indicated that an increase approximately as high as five times in the capability of injection molding may be achieved. Under the best setting condition, the cavity pressure profiles were relatively smooth and similar. Low screw rotational speed, high injection speed and short packing time led to the inconsistency elevation of injection molding.

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