scholarly journals Injection Molding Technique for Fabrication of Flexible Prosthesis from Flexible Thermoplastic Denture base Materials

2012 ◽  
Vol 3 (4) ◽  
pp. 303-307 ◽  
Author(s):  
Kunwarjeet Singh
Keyword(s):  
Injection Molding ◽  
Acrylic Resin ◽  
Injection Molding Process ◽  
Manufacturing Companies ◽  
Molding Process ◽  
Denture Base ◽  
Base Materials ◽  
Step Procedure ◽  
The Press ◽  
Different Types

ABSTRACT Purpose To know properties, step-by-step procedure for fabrication and insertion of flexible prosthesis. Background Flexible denture base materials were introduced to dentistry by the name of Valplast and Flexiplast in 1950's. Injection molding technique is used for fabrication of various types of prostheses from these materials and fluid resins. Pryor used injection molding technique for introducing unpolymerized acrylic resin into the mold. In the mid 1970's Ivoclar introduced an injection molding system which used an acrylic resin modified for the injection molding process. Recently, numbers of dental manufacturing companies have introduced injection molding systems. Materials and methods The flexible denture base materials are superpolyamides which are available in the form of granules in cylinders of different sizes. These materials are thermoplastic in nature and needed to be converted into fluid form before pouring into mold under pressure. Each cylinder should be plasticized for 15 to 20 minutes at 550 to 560°F in an electric cartridge furnace before injecting the material into the flask. While injecting, the cylinder should be aligned with opening of flask and the levers of the press should be turned rapidly to apply firm pressure until the springs of the press are fully compressed. The pressure should be maintained for 3 to 5 minutes and the flask should be allowed to bench cool for 15 to 20 minutes before opening. Conclusion This technique can be used for fabrication of different types of prostheses from flexible denture base materials and fluid resins. How to cite this article Singh K, Gupta N. Injection Molding Technique for Fabrication of Flexible Prosthesis from Flexible Thermoplastic Denture base Materials. World J Dent 2012;3(4):303-307.

scholarly journals The effect of virgin nylon addition into recycled nylon on the fatigue strength of thermoplastic nylon denture base

2020 ◽  
Vol 32 (1) ◽  
pp. 68
Author(s):  
Siti Wahyuni ◽  
Jeewena Ravichanthiran
Keyword(s):  
Fatigue Strength ◽  
Injection Molding ◽  
Mean Value ◽  
Laboratory Research ◽  
Injection Molding Process ◽  
Test Results ◽  
Molding Process ◽  
Denture Base ◽  
Experimental Laboratory ◽  
The Mean

Introduction: Thermoplastic nylon denture base is processed through injection molding process. This manipulation technique produces non-biodegradable nylon wastes which have to be recycled. Recycling of nylon wastes is feasible due to the linear molecular structure of thermoplastic nylon. This study aimed to know the effect of adding virgin nylon into recycled nylon on the fatigue strength of thermoplastic nylon denture base. Methods: This research was experimental laboratory research using 27 samples of thermoplastic nylon with three different groups (100% virgin nylon, 100% recycled nylon and combination of 60% of virgin nylon with 40% of recycled nylon) using injection molding technique. The test results were analyzed using one-way ANOVA test to know the differences in the mean value of the fatigue strength of each group and LSD test to know the effect of adding 60% of virgin nylon into 40% of recycled nylon. Resuts: Results showed significant results (p < 0,05), as well as LSD test that showed there is effect of adding 60% of virgin nylon into 40% of recycled nylon on the fatigue strength of thermoplastic nylon denture base. Conclusion: The combination of 60% of virgin nylon with 40% of recycled nylon showed higher fatigue strength than the recycled nylon.

Filling Behavior of Polymer Material into Sub-^|^mu;m Structure in Injection Molding Process

2013 ◽  
Vol 133 (4) ◽  
pp. 105-111
Author(s):  
Chisato Yoshimura ◽  
Hiroyuki Hosokawa ◽  
Koji Shimojima ◽  
Fumihiro Itoigawa
Keyword(s):  
Injection Molding ◽  
Polymer Material ◽  
Injection Molding Process ◽  
Molding Process

scholarly journals Study on External Gas-Assisted Mold Temperature Control with the Assistance of a Flow Focusing Device in the Injection Molding Process

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 965 ◽  
Author(s):  
Nguyen Truong Giang ◽  
Pham Son Minh ◽  
Tran Anh Son ◽  
Tran Minh The Uyen ◽  
Thanh-Hai Nguyen ◽  
...  
Keyword(s):  
Injection Molding ◽  
Temperature Control ◽  
Mold Temperature ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Flow Focusing ◽  
Molding Process ◽  
Heating Efficiency ◽  
Flow Length ◽  
Insert Plate

In the injection molding field, the flow of plastic material is one of the most important issues, especially regarding the ability of melted plastic to fill the thin walls of products. To improve the melt flow length, a high mold temperature was applied with pre-heating of the cavity surface. In this paper, we present our research on the injection molding process with pre-heating by external gas-assisted mold temperature control. After this, we observed an improvement in the melt flow length into thin-walled products due to the high mold temperature during the filling step. In addition, to develop the heating efficiency, a flow focusing device (FFD) was applied and verified. The simulations and experiments were carried out within an air temperature of 400 °C and heating time of 20 s to investigate a flow focusing device to assist with external gas-assisted mold temperature control (Ex-GMTC), with the application of various FFD types for the temperature distribution of the insert plate. The heating process was applied for a simple insert model with dimensions of 50 mm × 50 mm × 2 mm, in order to verify the influence of the FFD geometry on the heating result. After that, Ex-GMTC with the assistance of FFD was carried out for a mold-reading process, and the FFD influence was estimated by the mold heating result and the improvement of the melt flow length using acrylonitrile butadiene styrene (ABS). The results show that the air sprue gap (h) significantly affects the temperature of the insert and an air sprue gap of 3 mm gives the best heating rate, with the highest temperature being 321.2 °C. Likewise, the actual results show that the height of the flow focusing device (V) also influences the temperature of the insert plate and that a 5 mm high FFD gives the best results with a maximum temperature of 332.3 °C. Moreover, the heating efficiency when using FFD is always higher than without FFD. After examining the effect of FFD, its application was considered, in order to improve the melt flow length in injection molding, which increased from 38.6 to 170 mm, while the balance of the melt filling was also clearly improved.

scholarly journals Induced network-based transfer learning in injection molding for process modelling and optimization with artificial neural networks

2021 ◽  
Vol 112 (11-12) ◽  
pp. 3501-3513
Author(s):  
Yannik Lockner ◽  
Christian Hopmann
Keyword(s):  
Injection Molding ◽  
Transfer Learning ◽  
Injection Molding Process ◽  
Process Data ◽  
Molding Process ◽  
Melt Temperature ◽  
Processing Industry ◽  
Source Models ◽  
Plastics Processing ◽  
Artificial Neural

AbstractThe necessity of an abundance of training data commonly hinders the broad use of machine learning in the plastics processing industry. Induced network-based transfer learning is used to reduce the necessary amount of injection molding process data for the training of an artificial neural network in order to conduct a data-driven machine parameter optimization for injection molding processes. As base learners, source models for the injection molding process of 59 different parts are fitted to process data. A different process for another part is chosen as the target process on which transfer learning is applied. The models learn the relationship between 6 machine setting parameters and the part weight as quality parameter. The considered machine parameters are the injection flow rate, holding pressure time, holding pressure, cooling time, melt temperature, and cavity wall temperature. For the right source domain, only 4 sample points of the new process need to be generated to train a model of the injection molding process with a degree of determination R2 of 0.9 or and higher. Significant differences in the transferability of the source models can be seen between different part geometries: The source models of injection molding processes for similar parts to the part of the target process achieve the best results. The transfer learning technique has the potential to raise the relevance of AI methods for process optimization in the plastics processing industry significantly.

scholarly journals Constant Temperature Approach for the Assessment of Injection Molding Parameter Influence on the Fatigue Behavior of Short Glass Fiber Reinforced Polyamide 6

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1569
Author(s):  
Selim Mrzljak ◽  
Alexander Delp ◽  
André Schlink ◽  
Jan-Christoph Zarges ◽  
Daniel Hülsbusch ◽  
...  
Keyword(s):  
Injection Molding ◽  
Glass Fiber ◽  
Process Parameters ◽  
Fatigue Properties ◽  
Injection Molding Process ◽  
Molding Process ◽  
Short Glass Fiber ◽  
Glass Fiber Reinforced ◽  
Molding Parameter ◽  
Short Glass

Short glass fiber reinforced plastics (SGFRP) offer superior mechanical properties compared to polymers, while still also enabling almost unlimited geometric variations of components at large-scale production. PA6-GF30 represents one of the most used SGFRP for series components, but the impact of injection molding process parameters on the fatigue properties is still insufficiently investigated. In this study, various injection molding parameter configurations were investigated on PA6-GF30. To take the significant frequency dependency into account, tension–tension fatigue tests were performed using multiple amplitude tests, considering surface temperature-adjusted frequency to limit self-heating. The frequency adjustment leads to shorter testing durations as well as up to 20% higher lifetime under fatigue loading. A higher melt temperature and volume flow rate during injection molding lead to an increase of 16% regarding fatigue life. In situ Xray microtomography analysis revealed that this result was attributed to a stronger fiber alignment with larger fiber lengths in the flow direction. Using digital volume correlation, differences of up to 100% in local strain values at the same stress level for different injection molding process parameters were identified. The results prove that the injection molding parameters have a high influence on the fatigue properties and thus offer a large optimization potential, e.g., with regard to the component design.

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