Fast cavity surface temperature evolution in injection molding: control of cooling stage and final morphology analysis

RSC Advances ◽  
2016 ◽  
Vol 6 (101) ◽  
pp. 99274-99281 ◽  
Author(s):  
Sara Liparoti ◽  
Andrea Sorrentino ◽  
Giuseppe Titomanlio
Keyword(s):  
Injection Molding ◽  
Surface Temperature ◽  
Temperature Evolution ◽  
Cavity Surface ◽  
Cooling Stage ◽  
Morphology Analysis

New isotropic morphologies are obtained by controlling pressure and temperature evolution.

scholarly journals Replication of micro and nano-features on iPP by injection molding with fast cavity surface temperature evolution

2017 ◽  
Vol 133 ◽  
pp. 559-569 ◽  
Author(s):  
Vito Speranza ◽  
Sara Liparoti ◽  
Matteo Calaon ◽  
Guido Tosello ◽  
Roberto Pantani ◽  
...  
Keyword(s):  
Injection Molding ◽  
Surface Temperature ◽  
Temperature Evolution ◽  
Cavity Surface

scholarly journals Hierarchical Structure of iPP During Injection Molding Process with Fast Mold Temperature Evolution

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 424 ◽  
Author(s):  
Vito Speranza ◽  
Sara Liparoti ◽  
Roberto Pantani ◽  
Giuseppe Titomanlio
Keyword(s):  
Injection Molding ◽  
Surface Temperature ◽  
Hierarchical Structure ◽  
Flow Fields ◽  
Electrical Heating ◽  
Cavity Surface ◽  
Injection Molding Process ◽  
Mold Surface ◽  
Molding Process ◽  
Injection Molded

Mold surface temperature strongly influences the molecular orientation and morphology developed in injection molded samples. In this work, an isotactic polypropylene was injected into a rectangular mold, in which the cavity surface temperature was properly modulated during the process by an electrical heating device. The induced thermo-mechanical histories strongly influenced the morphology developed in the injection molded parts. Polarized optical microscope and atomic force microscope were adopted for morphological investigations. The combination of flow field and cooling rate experienced by the polymer determined the hierarchical structure. Under strong flow fields and high temperatures, a tightly packed structure, called shish-kebab, aligned along the flow direction, was observed. Under weak flow fields, the formation of β-phase, as cylindrites form, was observed. The formation of each morphological structure was analyzed and discussed on the bases of the flow and temperature fields, experienced by the polymer during each stage of the injection molding process.

scholarly journals Replication of Micro- and Nanofeatures in Injection Molding of Two PLA Grades with Rapid Surface-Temperature Modulation

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1442 ◽  
Author(s):  
Sara Liparoti ◽  
Vito Speranza ◽  
Roberto Pantani
Keyword(s):  
Injection Molding ◽  
Surface Temperature ◽  
Mold Temperature ◽  
Cavity Surface ◽  
Injection Molding Process ◽  
Temperature Modulation ◽  
Molding Process ◽  
Fast Heating ◽  
Crystallinity Degree ◽  
Replication Accuracy

The production by injection molding of polymeric components having micro- and nanometrical surfaces is a complex task. Generally, the accurate replication of micro- and nanometrical features on the polymeric surface during the injection-molding process is prevented by of the low mold temperature adopted to reduce cooling time. In this work, we adopt a system that allows fast heating of the cavity surface during the time the melt reaches the cavity, and fast cooling after heater deactivation. A nickel insert with micro- and nanofeatures in relief is located on the cavity surface. Replication accuracy is analyzed by Atomic Force Microscopy under different injection-molding conditions. Two grades of polylactic acid with different viscosity have been adopted. The results indicate that the higher the cavity surface temperature is, the higher the replication accuracy is. The viscosity has a significant effect only in the replication of the microfeatures, whereas its effect results are negligible in the replication of nanofeatures, thus suggesting that the interfacial phenomena are more important for replication at a nanometric scale. The evolution of the crystallinity degree on the surface also results in a key factor on the replication of nanofeatures.

Modelling the Packing Cooling Stage in Injection Molding of Amorphous Polymers

1988 ◽  
Vol 3 (4) ◽  
pp. 184-190 ◽  
Author(s):  
D. Huilier ◽  
J. Terrisse ◽  
M.-E. de la Lande ◽  
A. Latrobe
Keyword(s):  
Injection Molding ◽  
Amorphous Polymers ◽  
Cooling Stage

scholarly journals The Feasibility of an Internal Gas-Assisted Heating Method for Improving the Melt Filling Ability of Polyamide 6 Thermoplastic Composites in a Thin Wall Injection Molding Process

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1004 ◽  
Author(s):  
Thanh Trung Do ◽  
Tran Minh The Uyen ◽  
Pham Son Minh
Keyword(s):  
Injection Molding ◽  
Heating Rate ◽  
Temperature Control ◽  
Cavity Surface ◽  
Heating Process ◽  
Injection Molding Process ◽  
Thin Wall ◽  
Molding Process ◽  
Filling Ability ◽  
Wall Injection

In thin wall injection molding, the filling of plastic material into the cavity will be restricted by the frozen layer due to the quick cooling of the hot melt when it contacts with the lower temperature surface of the cavity. This problem is heightened in composite material, which has a higher viscosity than pure plastic. In this paper, to reduce the frozen layer as well as improve the filling ability of polyamide 6 reinforced with 30 wt.% glass fiber (PA6/GF30%) in the thin wall injection molding process, a preheating step with the internal gas heating method was applied to heat the cavity surface to a high temperature, and then, the filling step was commenced. In this study, the filling ability of PA6/GF30% was studied with a melt flow thickness varying from 0.1 to 0.5 mm. To improve the filling ability, the mold temperature control technique was applied. In this study, an internal gas-assisted mold temperature control (In-GMTC) using different levels of mold insert thickness and gas temperatures to achieve rapid mold surface temperature control was established. The heating process was observed using an infrared camera and estimated by the temperature distribution and the heating rate. Then, the In-GMTC was employed to produce a thin product by an injection molding process with the In-GMTC system. The simulation results show that with agas temperature of 300 °C, the cavity surface could be heated under a heating rate that varied from 23.5 to 24.5 °C/s in the first 2 s. Then, the heating rate decreased. After the heating process was completed, the cavity temperature was varied from 83.8 to about 164.5 °C. In-GMTC was also used for the injection molding process with a part thickness that varied from 0.1 to 0.5 mm. The results show that with In-GMTC, the filling ability of composite material clearly increased from 2.8 to 18.6 mm with a flow thickness of 0.1 mm.

Fast mold surface temperature evolution: relevance of asymmetric surface heating for morphology of iPP molded samples

RSC Advances ◽  
2015 ◽  
Vol 5 (46) ◽  
pp. 36434-36448 ◽  
Author(s):  
S. Liparoti ◽  
A. Sorrentino ◽  
G. Guzman ◽  
M. Cakmak ◽  
G. Titomanlio
Keyword(s):  
Surface Temperature ◽  
Molecular Orientation ◽  
Mold Temperature ◽  
Surface Heating ◽  
Temperature Evolution ◽  
Mold Surface

It is widely accepted that mold temperature has a strong effect on the amount of molecular orientation and morphology developed in a non-isothermal flowing melt.

Multidecadal Climate Variability in Observed and Modeled Surface Temperatures*

2008 ◽  
Vol 21 (5) ◽  
pp. 1104-1121 ◽  
Author(s):  
Sergey Kravtsov ◽  
Christopher Spannagle
Keyword(s):  
Climate Variability ◽  
Surface Temperature ◽  
Thermohaline Circulation ◽  
North Pacific Ocean ◽  
Coupled Model ◽  
Atlantic Multidecadal Oscillation ◽  
Temperature Evolution ◽  
Past Century ◽  
The North ◽  
Surface Temperatures

Abstract This study identifies interdecadal natural climate variability in global surface temperatures by subtracting, from the observed temperature evolution, multimodel ensemble mean based on the World Climate Research Programme's (WCRP) Coupled Model Intercomparison Project phase 3 (CMIP3) multimodel dataset. The resulting signal resembles the so-called Atlantic multidecadal oscillation (AMO) and is presumably associated with intrinsic dynamics of the oceanic thermohaline circulation (THC). While certain phases of the oscillation are dominated by the anomalies in the North Atlantic region, other phases are characterized by global teleconnections to the North Pacific Ocean, tropical Atlantic Ocean, as well as the Southern Ocean. In particular, natural variability of sea surface temperature in the Atlantic hurricanes’ main development region has a peak-to-peak amplitude comparable in magnitude to this region’s surface temperature increase over the past century, for all seasons. Evidence suggests that the AMO influence on secular trends in the global-mean surface temperature can arise via direct, regional contribution to the surface temperature evolution, as well as via an indirect route linked to variability of the oceanic uptake of CO2 associated with AMO-related THC changes.

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.

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