scholarly journals Design of a Combined Redrawing-Ironing Process to Manufacture a CNG Pressure Vessel Liner

2021 ◽  
Vol 11 (18) ◽  
pp. 8295
Author(s):  
Gunyoung Park ◽  
Rockkyu Park ◽  
Hyoseo Kwak ◽  
Chul Kim
Keyword(s):  
Pressure Vessel ◽  
Deep Drawing ◽  
Processing Time ◽  
Continuous Process ◽  
Installation Space ◽  
Theoretical Formula ◽  
Manufacturing Cost ◽  
Second Stage ◽  
Forming Load ◽  
Forming Defects

The liner of a compressed natural gas pressure vessel is manufactured by D.D.I. (Deep Drawing and Ironing), which is a continuous process that uses deep drawing to reduce the diameter of a billet and ironing to reduce the thickness of the billet. In the second stage of the existing D.D.I. process, drawing and two steps of ironing have been performed separately with different dies, which requires a long processing time, high manufacturing cost, and installation space. To solve the above problems, this study suggests a new second stage using a combined redrawing-ironing die. A theoretical formula to calculate the forming load of the combined redrawing-ironing process was established and verified with finite element analysis results. The forming load, maximum thickness reduction ratio in the second stage, and forming defects in the third stage were analyzed by varying the redrawing-ironing ratio in the second stage. The results show that the number of dyes (3 → 1), punch diameter (394.1 mm → 383 mm), and processing time (39.8 s → 20 s) in the second stage were obtained to save production time and cost.

Passive Alignment of Optical Fiber in a V-Groove With Low Viscosity Epoxy Flow

2003 ◽  
Author(s):  
Jeffery C. C. Lo ◽  
C. S. Yung ◽  
S. W. Ricky Lee ◽  
Steve H. K. Lee ◽  
J. S. Wu ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Processing Time ◽  
Cover Plate ◽  
Manufacturing Cost ◽  
Optoelectronic Packaging ◽  
Low Viscosity ◽  
Epoxy Dispensing ◽  
A New Technique ◽  
Passive Alignment

The alignment of optical fibers is very critical in optoelectronic packaging. A slight offset in any direction may severely affect the performance of the photonic device. Recently, passive alignment of optical fibers has attracted substantial attention due to its lower manufacturing cost and faster processing time when compared with active alignment. For conventional passive alignment, the position of each optical fiber is defined by the geometry of a V-groove. The epoxy is dispensed from the top of the V-groove and another cover plate is usually required to press the fiber against the walls of the V-groove. In the present study, a new technique for epoxy dispensing is developed. Instead of being applied from the top of the V-groove, some low viscosity epoxy is dispensed in a “canal” first. The epoxy fills an adjacent “reservoir” and then flows into the V-groove. Subsequently the epoxy flow runs through the gap between the optical fiber and the V-groove walls. It is observed that the flow of epoxy can align the optical fiber by the surface tension. Once the optical fiber is aligned and the epoxy is cured, more epoxy is applied in a glob-top manner to mechanical enhancement. In this paper, the configuration of the V-groove and associated features, the epoxy dispensing process, and the results of alignment are presented in details.

SVM-BASED PHONEME CLASSIFICATION AND LIP SHAPE REFINEMENT IN REAL-TIME LIP-SYNCH SYSTEM

2006 ◽  
Vol 20 (07) ◽  
pp. 1029-1051 ◽  
Author(s):  
HANSEOK KO ◽  
DAVID K. HAN
Keyword(s):  
Real Time ◽  
Processing Time ◽  
Support Vector ◽  
Mel Frequency Cepstral Coefficients ◽  
Phoneme Classification ◽  
Second Stage ◽  
Single Frame ◽  
Time Operation ◽  
Real Time Operation ◽  
Coarse To Fine

In this paper, we present a real time lip-synch system that activates 2-D avatar's lip motion in synch with incoming speech utterance. To achieve the real time operation of the system, the processing time was minimized by "merge and split" procedures resulting in coarse-to-fine phoneme classification. At each stage of phoneme classification, the support vector machine (SVM) method was applied to reduce the computational load while maintaining the desired accuracy. The coarse-to-fine phoneme classification, is accomplished via two_stages of feature extraction: in the first stage, each speech frame is acoustically analyzed for three classes of lip opening using Mel Frequency Cepstral Coefficients (MFCC) as a feature; in the second stage, each frame is further refined for detailed lip shape using formant information. The method was implemented in 2-D lip animation and it was demonstrated that the system was effective in accomplishing real-time lip-synch. This approach was tested on a PC using the Microsoft Visual Studio with an Intel Pentium IV 1.4 Giga Hz CPU and 384 MB RAM. It was observed that the methods of phoneme merging and SVM achieved about twice the speed in recognition than the method employing the Hidden Markov Model (HMM). A typical latency time per a single frame observed using the proposed method was in the order of 18.22 milliseconds while an HMM method under identical conditions resulted about 30.67 milliseconds.

Influence of the Key Process Parameters in Hydrodynamic Deep Drawing Utilizing a Combined Floating and Static Die Cavity

2021 ◽  
Author(s):  
Huiting Wang ◽  
Jianfei Kong ◽  
Hongbo Pan ◽  
Jinxiu Fang ◽  
Xiaohui Shen
Keyword(s):  
Process Parameters ◽  
Deep Drawing ◽  
Initial Pressure ◽  
Loading Path ◽  
Maximum Pressure ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Hydraulic Loading ◽  
Second Stage ◽  
Hydrodynamic Deep Drawing

Abstract This study focus on the effects of the key process parameters during a modified hydrodynamic deep drawing utilizing a combined floating and static die cavity (HDDC). A two-stage hydraulic loading path is recommended in the novel process, and each stage of the hydraulic loading path is a linear loading path with an inflection point. The method to evaluate the wrinkle and forming dimension precision of the formed parts is introduced at first. Then the influence of the key parameters of the two-stage hydraulic loading path as well as the blank holder force on the dimension accuracy and surface quality of the formed parts was studied in detail. The results showed that the influence of the liquid pressure during the second stage is more significant than that in the first stage in hydrodynamic deep drawing utilizing a combined floating and static die cavity. The initial pressure of the second stage and the maximum pressure arriving moment during this stage have a significant impact on the dimensional accuracy of the formed parts, and the smaller initial pressure or the later the maximum pressure of the second stage arrives, the higher the accuracy of the formed part is. Similarly, the influence of the blank holder force in the second stage on the forming accuracy is more significant than that in the first stage.

An integrated CAD/CAM system for CNG pressure vessel manufactured by deep drawing and ironing operation

2004 ◽  
Vol 18 (6) ◽  
pp. 904-914
Author(s):  
Joon-Hong Park ◽  
Chul Kim ◽  
Jae-Chan Choi
Keyword(s):  
Pressure Vessel ◽  
Deep Drawing ◽  
Cad Cam

Compression Processes and Performance Analysis of a High-Pressure Reciprocating Gas Compressor

1996 ◽  
Vol 210 (2) ◽  
pp. 153-165
Author(s):  
T T Wu ◽  
W H Hsieh
Keyword(s):  
High Pressure ◽  
Manufacturing Cost ◽  
Dimensional Model ◽  
Stroke Length ◽  
Second Stage ◽  
Significant Temperature ◽  
Compressor Performance ◽  
Convergent Flow ◽  
And Performance ◽  
Calculated Velocity

Compression processes and compressor performance in a two-stage 41.34 MPa (6000 lb/in2) reciprocating gas compressor were investigated by transient multi-dimensional and transient global thermodynamic models. The transient multi-dimensional model was adopted to predict the two-dimensional compression processes in the second-stage cylinder of the high-pressure reciprocating gas compressor. Calculated results showed no significant temperature gradients anywhere in the compressor cylinder except near the wall, throughout one complete compressor cycle. On the other hand, the calculated velocity fields and streamline contours showed a convergent flow pattern during the process of compression with discharge and a large recirculation vortex during the process of expansion with suction. A parametric study based on the transient global thermodynamic model was conducted to investigate the effect of various parameters, that is clearance volume, wall temperature of cylinder head and stroke length, on the compressor performance. Among these parameters, it was found that the clearance volume had the strongest effect on the compressor performance. A reduced clearance volume increased volumetric efficiency. Also, it was found that decreasing the stroke length would not degrade the compressor performance, but it could reduce the compressor size and thereby the manufacturing cost significantly.

scholarly journals A New Successive Forming Process for Large Modulus Gears

2020 ◽  
Author(s):  
Yao Lin ◽  
Tao Wu ◽  
Guangchun Wang
Keyword(s):  
Spur Gears ◽  
Forming Process ◽  
Forming Quality ◽  
Gear Teeth ◽  
Second Stage ◽  
Forming Load ◽  
Single Tooth ◽  
New Process ◽  
Plastic Forming ◽  
Good Potential

Abstract A successive tooth forming process for producing large modulus spur gears (m＞2.5 mm) was firstly proposed in this paper to break the restrictions of large forming load and large equipment structure of traditional plastic forming. It contains the preforming stage and finishing stage. In the first stage, the die with a single-tooth preformed gear teeth one by one through several passes. In the second stage, the other die with multi-teeth refined the preformed teeth into required shape. The influence of total pressing depth and feed distribution in preforming stage on final forming quality was analyzed by numerical simulation and the reasonable process parameters had been presented. Gears without fold defects were well formed both in simulations and experiments, proving the feasibility of this method. The new process has advantages of smaller forming load and simpler tooling set, which shows a good potential for manufacturing large modulus spur gears.

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