COMPUTATIONAL MODELING OF THREE-DIMENSIONAL COMPRESSIBLE FILLING PROCESS OF INJECTION MOLDING

Author(s):  
Mustafa Tutar ◽  
Ali Karakus
2016 ◽  
Vol 36 (8) ◽  
pp. 861-866 ◽  
Author(s):  
Quan Wang ◽  
Zhenghuan Wu

Abstract This paper presents a study of the characteristics of axial vibration of a screw in the filling process for a novel dynamic injection molding machine. By simplifying a generalized model of the injection screw, physical and mathematic models are established to describe the dynamic response of the axial vibration of a screw using the method of lumped-mass. The damping coefficient of the screw is calculated in the dynamic filling process. The amplitude-frequency characteristics are analyzed by the simulation and experimental test of polypropylene. The results show that the amplitude of a dynamic injection molding machine is not only is related to structure parameters of the screw and performance of the material, such as non-Newtonian index, but also depends on the processing parameters, such as vibration intensity and injection speed.


2012 ◽  
Vol 217-219 ◽  
pp. 1998-2001
Author(s):  
Tie Geng ◽  
Qing Hai Ren ◽  
Wei Qing Tu ◽  
Dan Dan Liu

According to the color contour map of the 3D injection molding simulation results, the commonly used color contour map drawing algorithm was researched, and a three-dimensional color image rendering algorithm which based on the "physical field values and color range mapping" was given too. And the key technologies of the algorithm which was used to draw 3D color contour map were introduced in detail. In the end, an example was given.


2001 ◽  
Author(s):  
Florin Ilinca ◽  
Jean-François Hétu

Abstract This paper presents simulations of co-injection molding problems computed by a three-dimensional finite element method. The polymer melts behave as generalized Newtonian fluids and non-isothermal effects are taken into account. In addition to the momentum, mass and energy equations, we solve two transport equations tracking the polymer/air and skin/core polymers interfaces. Solutions are shown for a center gated rectangular plate. The effect of varying the melt/mold temperature and the ratio between the skin and core materials is investigated. The solution obtained for the same skin and core materials is compared with those in which viscosities of core and skin materials are different. Finally, the solution for the co-injection of a C-shaped plate is presented.


2004 ◽  
Vol 127 (3) ◽  
pp. 324-334 ◽  
Author(s):  
Chien-Chang Pei ◽  
Sheng-Jye Hwang

The plastic packaging process for integrated circuits is subject to several fabrication defects. For packages containing leadframes, three major defects may occur in the molding process alone, namely, incomplete filling and void formation, wire sweep, and paddle shift. Paddle shift is the deflection of the leadframe pad and die. Excessive paddle shift reduces the encapsulation protection for the components and may result in failures due to excessive wire sweep. Computer-aided analysis is one of the tools that could be used to simulate and predict the occurrence of such molding-process-induced defects, even prior to the commencement of mass production of a component. This paper presents a methodology for computational modeling and prediction of paddle shift during the molding process. The methodology is based on modeling the flow of the polymer melt around the leadframe and paddle during the filling process, and extracting the pressure loading induced by the flow on the paddle. The pressure loading at different times during the filling process is then supplied to a three-dimensional, static, structural analysis module to determine the corresponding paddle deflections at those times. The paper outlines the procedures used to define the relevant geometries and to generate the meshes in the “fluid” and “structural” subdomains, and to ensure the compatibility of these meshes for the transfer of pressure loadings. Results are shown for a full paddle shift simulation. The effect on the overall model performance of different element types for the mold-filling analysis and the structural analysis is also investigated and discussed. In order to obtain more accurate results and in a shorter computational time for the combined (fluid and structural) paddle shift analysis, it was found that higher-order elements, such as hexahedra or prisms, are more suitable than tetrahedra.


2017 ◽  
Vol 742 ◽  
pp. 807-814 ◽  
Author(s):  
Christoph Doerffel ◽  
Ricardo Decker ◽  
Michael Heinrich ◽  
Jürgen Tröltzsch ◽  
Mirko Spieler ◽  
...  

Polymer matrix compounds based on piezo ceramic and electrically conducting particles within a thermoplastic matrix show distinctive piezoelectric and dielectric effects which can used for sensor applications. The electrical and mechanical properties can be adjusted in a wide range by varying the ratio of active filling particles and the matrix materials. The sensor effect of the compound is generated by the ceramic particles. A large ratio of piezo ceramic powder facilitates a high sensitivity. The electrical permittivity of the otherwise insulating matrix polymer can be adjusted by the amount of conductive filler. An aligned permittivity leads to a stronger electrical field in the ceramic particles. In contrast, too many conductive particles create a conductive network in the compound which short-circuits the sensors. The piezo ceramic compounds can be processed via micro injection molding for application as ceramic sensors. This offers a wide range of new sensor design variants, notably three-dimensional and highly complex geometries. However, there are two main demands for a highly sensitive sensor, which are conflicting. On the one hand the filler content of piezo ceramic particles in combination with electrical conductive carbon nanotubes must be very high, on the other hand the wall thickness should be as thin as possible. For filling cavities with a high aspect-ratio in an injection molding process, low viscosity polymer melts are necessary. These process characteristics conflict with the increasing viscosity by filling the melt with the particles. The sensor measuring area has to be designed as thin walled as possible. In order to overcome this obstacle a dynamically tempered mold design is applied to avoid solidification of the melt, before the mold is completely filled. The mold can be tempered by Peltier elements. The fully electric tempering is cleaner, more precise and more reliable than conventional water or oil tempering.


Author(s):  
D. E. O. Dewi ◽  
T. L. R. Mengko ◽  
I. K. E. Purnama ◽  
A. G. Veldhuizen ◽  
M. H. F. Wilkinson

Hole-filling in ultrasound volume reconstruction using freehand three-dimensional ultrasound estimates the values for empty voxels from the unallocated voxels in the Bin-filling process due to inadequate sampling in the acquisition process. Olympic operator, as a neighbourhood averaging filter, can be used to estimate the empty voxel. However, this method needs improvement to generate a closer estimation of the empty voxels. In this paper, the authors propose an improved Olympic operator for the Hole-filling algorithm, and apply it to generate the volume in a 3D ultrasound reconstruction of the spine. The conventional Olympic operator defines the empty voxels by sorting the neighbouring voxels, removing the n% of the upper and lower values, and averaging them to attain the value to fill the empty voxels. The empty voxel estimation can be improved by thresholding the range width of its neighbouring voxels and adjusting it to the average values. The method is tested on a hole-manipulated volume derived from a cropped 3D ultrasound volume of a part of the spine. The MAE calculation on the proposed technique shows improved result compared to all tested existing methods.


Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1507 ◽  
Author(s):  
Miguel A. Hidalgo-Salazar ◽  
Juan P. Correa-Aguirre ◽  
Serafín García-Navarro ◽  
Luis Roca-Blay

In this study, the properties of a polyolefin blend matrix (PP-HDPE) were evaluated and modified through the addition of raw coir coconut fibers-(CCF). PP-HDPE-CCF biocomposites were prepared using melt blending processes with CCF loadings up to 30% (w/w). CCF addition generates an increase of the tensile and flexural modulus up to 78% and 99% compared to PP-HDPE blend. This stiffening effect is caused by a decrease in the polymeric chain mobility due to CCF, the higher mechanical properties of the CCF compared to the polymeric matrix and could be an advantage for some biocomposites applications. Thermal characterizations show that CCF incorporation increases the PP-HDPE thermal stability up to 63 °C, slightly affecting the melting behavior of the PP and HDPE matrix. DMA analysis shows that CCF improves the PP-HDPE blend capacity to absorb higher external loads while exhibiting elastic behavior maintaining its characteristics at higher temperatures. Also, the three-dimensional microscopy study showed that CCF particles enhance the dimensional stability of the PP-HDPE matrix and decrease manufacturing defects as shrinkage in injected specimens. This research opens a feasible opportunity for considering PP-HDPE-CCF biocomposites as alternative materials for the design and manufacturing of sustainable products by injection molding.


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