Computational Modeling and Validation of the Encapsulation of Plastic Packages by Transfer Molding

1999 ◽  
Vol 122 (2) ◽  
pp. 138-146 ◽  
Author(s):  
L. Nguyen ◽  
C. Quentin ◽  
W. Lee ◽  
S. Bayyuk ◽  
S. A. Bidstrup-Allen ◽  
...  
Keyword(s):  
Computational Modeling ◽  
Experimental Measurements ◽  
Computational Studies ◽  
Computational Results ◽  
Flow Front ◽  
Transfer Molding ◽  
Plastic Packages ◽  
Encapsulation Process ◽  
Computational Predictions ◽  
Good Agreement

This paper presents, discusses, and compares results from experimental and computational studies of the plastic encapsulation process for a 144-lead TQFP package. The experimental results were obtained using an instrumented molding press, while the computational predictions were obtained using a newly-developed software for modeling transfer molding processes. Validation of the software is emphasized, and this was done mainly by comparing the computational results with the corresponding experimental measurements for pressure, temperature, and flow front advancement in the cavities and runners. The experimental and computational results were found to be in good agreement, especially for the flow-front shapes and locations. [S1043-7398(00)00502-8]

Mechanical Deformation of Leadframe Assemblies in Plastic Packages During Molding

1991 ◽  
Vol 113 (4) ◽  
pp. 421-425 ◽  
Author(s):  
E. Suhir ◽  
L. T. Manzione
Keyword(s):  
Process Parameters ◽  
State Of The Art ◽  
Mechanical Deformation ◽  
Flow Front ◽  
Transfer Molding ◽  
Plastic Packages ◽  
Maximum Value ◽  
Significant Difference ◽  
The Difference ◽  
Maximum Stresses

We evaluate the maximum stresses and deflections in electric leads subjected to flow induced forces during transfer molding of plastic packages. It is found that lead deflection is proportional to the fifth power of the lead length and the inverse third power of lead thickness. These dependencies explain why it is more difficult to mold high pin count packages which have significantly longer and thinner leads to accommodate the higher interconnection density. In addition we find that the maximum value of the elastic lead deformation is about 0.9 mm (35 mils) for large state-of-the-art packages; exceeding this value causes permanent (plastic) lead distortion that compromises the symmetry of the package. We find also that minimizing the difference in flow front locations through careful gate design, and lowering the velocity over the leads by using balanced mold filling can make a significant difference in lead deformation. The results obtained are useful in establishing the appropriate geometry of the leads, as well as in choosing the materials and process parameters, so that excessive stresses and lead deflections can be avoided.

scholarly journals A Design Tool for Clothing Applications: Wind Resistant Fabric Layers and Permeable Vents

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Phillip Gibson ◽  
Michael Sieber ◽  
Jerry Bieszczad ◽  
John Gagne ◽  
David Fogg ◽  
...  
Keyword(s):  
Design Tool ◽  
Thermal Manikin ◽  
Experimental Measurements ◽  
Transfer Coefficients ◽  
Design Features ◽  
Clothing Design ◽  
Film Layer ◽  
Sweating Thermal Manikin ◽  
Computational Predictions ◽  
Good Agreement

A computational clothing design tool is used to examine the effects of different clothing design features upon performance. Computational predictions of total heat and mass transfer coefficients of the clothing design tool showed good agreement with experimental measurements obtained using a sweating thermal manikin for four different clothing systems, as well as for the unclothed bare manikin. The specific clothing design features examined in this work are the size and placement of air-permeable fabric vents in a protective suit composed primarily of a fabric-laminated polymer film layer. The air-permeable vents were shown to provide additional ventilation and to significantly decrease both the total thermal insulation and the water vapor resistance of the protective suit.

scholarly journals Design, Synthesis, Biological Evaluation, and Computational Studies of Novel Tri-Aryl Imidazole-Benzene Sulfonamide Hybrids as Promising Selective Carbonic Anhydrase IX and XII Inhibitors

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4718
Author(s):  
Lamya H. Al-Wahaibi ◽  
Bahaa G. M. Youssif ◽  
Ehab S. Taher ◽  
Ahmed H. Abdelazeem ◽  
Antar A. Abdelhamid ◽  
...  
Keyword(s):  
Proliferative Activity ◽  
Docking Studies ◽  
Biological Evaluation ◽  
Selectivity Ratio ◽  
Computational Studies ◽  
Design Synthesis ◽  
Ca Ix ◽  
Side Pocket ◽  
Modelling Simulation ◽  
Good Agreement

A novel series of tri-aryl imidazole derivatives 5a–n carrying benzene sulfonamide moiety has been designed for their selective inhibitory against hCA IX and XII activity. Six compounds were found to be potent and selective CA IX inhibitors with the order of 5g > 5b > 5d > 5e > 5g > 5n (Ki = 0.3–1.3 μM, and selectivity ratio for hCA IX over hCA XII = 5–12) relative to acetazolamide (Ki = 0.03 μM, and selectivity ratio for hCA IX over hCA XII = 0.20). The previous sixth inhibitors have been further investigated for their anti-proliferative activity against four different cancer cell lines using MTT assay. Compounds 5g and 5b demonstrated higher antiproliferative activity than other tested compounds (with GI50 = 2.3 and 2.8 M, respectively) in comparison to doxorubicin (GI50 = 1.1 M). Docking studies of these two compounds adopted orientation and binding interactions with a higher liability to enter the active side pocket CA-IX selectively similar to that of ligand 9FK. Molecular modelling simulation showed good agreement with the acquired biological evaluation.

The Behaviour of Multiple Loops in Torsion

1988 ◽  
Vol 15 (3) ◽  
pp. 149-156 ◽  
Author(s):  
R. A. Cavina ◽  
N. E. Waters
Keyword(s):  
Energy Method ◽  
Strain Energy ◽  
Vertical Axis ◽  
Experimental Measurements ◽  
Complementary Strain ◽  
Radial Axis ◽  
Strain Energy Method ◽  
Good Agreement

The angular stiffness of a multiple looped span, subject to rotation about a vertical axis (torsion) and also to rotation about a horizontal or radial axis (mesio-distal tilt), have been derived using the complementary (strain) energy method. Experimental measurements on enlarged models were in good agreement with the values calculated from the theoretical relationships obtained. The variations in angular stiffness resulting from changes in the loop height, width, and position of clinical sized loops are discussed.

ELECTRONIC STRUCTURE AND OPTICAL PROPERTIES OF CRYSTALLINE C60

1992 ◽  
Vol 06 (06) ◽  
pp. 309-321 ◽  
Author(s):  
W.Y. CHING ◽  
MING-ZHU HUANG ◽  
YONG-NIAN XU ◽  
FANQI GAN
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Optical Spectrum ◽  
Local Density ◽  
Low Dielectric Constant ◽  
Experimental Measurements ◽  
Absorption Bands ◽  
Low Dielectric ◽  
Good Agreement

The electronic structure and optical properties of crystalline C 60 and their pressure dependence have been studied by first-principles local density calculations. It is shown that fcc C 60 has a low dielectric constant and an optical spectrum rich in structures. The spectrum shows five disconnected absorption bands in the 1.4 to 7.0 eV region with sharp structures in each band that can be attributed to critical point transitions. This is a manifestation of the localized molecular structure coupled with long range crystalline order unique to the C 60 crystal. At a sufficient high pressure, the structures in the optical spectrum start to merge due to the merging of the bands. These results are in good agreement with some recent experimental measurements.

ACOUSTIC THREE-DIMENSIONAL EFFECTS AROUND THE TAIWAN STRAIT: COMPUTATIONAL RESULTS

1999 ◽  
Vol 07 (01) ◽  
pp. 15-26 ◽  
Author(s):  
CHI-FANG CHEN ◽  
JANG-JIA LIN ◽  
DING LEE
Keyword(s):  
Field Data ◽  
Bottom Topography ◽  
Three Dimensional ◽  
Propagation Model ◽  
Computational Results ◽  
Submarine Canyons ◽  
Offshore Area ◽  
Ocean Environment ◽  
The Taiwan Strait ◽  
Good Agreement

A set of experiments were performed in the offshore area off the coasts of Taiwan and three-dimensional (3-D) measurements recorded. The 3-D effect on underwater propagation due to azimuthal variation of bottom topography is studied for the offshore regions southwest of Taiwan, where submarine canyons exist. A 3-D acoustic propagation model, FOR3D, is used to detect the 3-D effect. Computational results show that the 3-D effect is more prominent along the axis of the canyon than across it. Calculations show a very good agreement with field data, which indicate that the 3-D effect exists in this realistic ocean environment.

A Theoretical Analysis on Resin Injection/Compression Molding

2007 ◽  
Vol 334-335 ◽  
pp. 209-212 ◽  
Author(s):  
Akbar Shojaei ◽  
A. Spah
Keyword(s):  
Analytical Solutions ◽  
Mold Filling ◽  
Compression Molding ◽  
Fiber Content ◽  
Flow Front ◽  
Transfer Molding ◽  
Unidirectional Flow ◽  
Resin Injection ◽  
Filling Time ◽  
Injection Compression Molding

In the present investigation, mold filling process of resin injection/compression molding (RI/CM) is compared with resin transfer molding (RTM) for simple mold geometry. To do this, analytical solutions are obtained for RI/CM in unidirectional flow. Based on the analytical solutions, flow front progression and pressure distribution are compared with RTM at different fiber content. The results indicate that the RI/CM reduces the mold filling time significantly, particularly for composite parts with higher fiber content.

A new look at filter backwash hydraulics

2001 ◽  
Vol 1 (2) ◽  
pp. 65-72 ◽  
Author(s):  
Ömer Akgiray ◽  
Ahmet M. Saatçı
Keyword(s):  
Experimental Measurements ◽  
New Approach ◽  
Ergun Equation ◽  
Mathematical Formulas ◽  
Good Agreement ◽  
New Look

A new approach to model media expansion during filter backwash is presented. The proposed approach is based on the assumption that the Ergun equation remains valid after fluidization. Mathematical formulas are derived for predicting expanded porosity for a given backwash velocity or backwash velocity for a given expanded porosity. These formulas can be easily used by the engineer. Values predicted using the proposed approach are in good agreement with experimental measurements.

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