Numerical Evaluation on the Curve Deviation of the Molded Glass Lens

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Jian Zhou ◽  
Mujun Li ◽  
Yang Hu ◽  
Tianyi Shi ◽  
Yueliang Ji ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Good Reason ◽  
Processing Parameters ◽  
Forming Process ◽  
Molding Process ◽  
Contact Heat ◽  
Thermal Boundary Conditions ◽  
Glass Lens ◽  
Final Profile ◽  
Relationship Of

The compression molding of precision glass lens is a near net-shape forming process for optical components fabrication. The final profile curve accuracy is one of the most crucial criterions for evaluating the quality of the molded lens. In this research, our purpose was focused on the evaluation of the molded lens curve deviation. By incorporating stress relaxation and structural relaxation model of glass, numerical simulations of the whole molding process for fabricating a planoconvex lens were conducted by utilizing the commercial software msc Marc. The relationship of the three variables, i.e., the lens curve deviation, the mold curve deviation, the gap between the lens and the lower mold, was discussed and the evolution plots with time of the three variables were obtained. Details of the thermal boundary conditions were discussed by considering the contact heat transfer behavior. Then the essentiality of a small gap between the molds and the molded lens after releasing the upper mold was demonstrated. In details, the sensitivity analysis of the processing parameters was conducted, such as the releasing temperature, the cooling rate in the annealing and fast cooling stage, respectively, and the magnitude of the hold-up force. The results showed that the glass lens curve deviation was not sensitive to the choices of the releasing temperature and the cooling rate. What's more, the results indicated that the curve deviation decreased with the hold-up force increasing. Finally, with all the details considered, the final simulation results were presented accurately with good reason.

scholarly journals Study on Mechanism of Glass Molding Process for Fingerprint Lock Glass Plates

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 394
Author(s):  
Wuyi Ming ◽  
Haojie Jia ◽  
Heyuan Huang ◽  
Guojun Zhang ◽  
Kun Liu ◽  
...  
Keyword(s):  
Residual Stress ◽  
Heat Conduction ◽  
Cooling Rate ◽  
Heating Rate ◽  
Relaxation Model ◽  
Glass Panel ◽  
Forming Process ◽  
Molding Process ◽  
Shape Deviation ◽  
Glass Forming

Curved glass is widely used in 3C industry, and the market demand is increasing gradually. Glass molding process (GMP) is a high-precision, high-efficiency 3D glass touch panel processing technology. In this study, the processing parameters of fingerprint lock glass panels were deeply analyzed. This paper first introduces the molding process of the glass panel, discusses the glass forming device, and explains the heat conduction principle of the glass. Firstly, it introduces the forming process of the glass panel, discusses the glass forming device, and explains the heat conduction principle of the glass. Secondly, the simulation model of a fingerprint lock glass plate was simulated by MSC. Marc software. The stress relaxation model and structure relaxation model are used in the model, and the heat transfer characteristics of glass mold are combined to accurately predict the forming process of glass components. The effects of molding temperature, heating rate, holding time, molding pressure, cooling rate and other process parameters on product quality characteristics (residual stress and shape deviation) were analyzed through simulation experiments. The results show that, in a certain range, the residual stress is inversely proportional to the bending temperature and heating rate, and is directly proportional to the cooling rate, while the shape deviation decreases with the increase of temperature and heating rate. When the cooling rate decreases, the shape deviation first decreases and then increases. Furthermore, a verification experiment is designed to verify the reliability of the simulation results by measuring and calculating the surface roughness of the formed products.

Numerical Study of Thickness Distribution of Stretch-Blow Bottles for Defects Prediction

2009 ◽  
Vol 413-414 ◽  
pp. 691-698 ◽  
Author(s):  
Ya Yue Pan ◽  
Shui Ying Zheng ◽  
Xiao Hong Pan
Keyword(s):  
Numerical Study ◽  
Thickness Distribution ◽  
Processing Parameters ◽  
Technological Parameters ◽  
Forming Process ◽  
Molding Process ◽  
Pet Bottles ◽  
Blow Molding ◽  
Stretch Blow Molding ◽  
Good Agreement

Nowadays, polyethylene terephthalate (PET) bottles have been increasingly used as drink containers. They are usually manufactured by a stretch-blow molding process. The improper parameters set in the stretch blow molding process may lead to many defects in the stretch-blow bottle. Finite Element (FE) simulations of the forming process were performed in this paper. The influences of the technological parameters, such as the balance between stretching and blowing rate, the movement of the stretch rod and the inflation pressure, were studied. As a result, the defects, such as over-thin area, cracking and deformation, can be predicted by this method. Especially, it is shown that the cracking in the bottom of products may result from the improper values of the dwell time and the stretch rate. The trends shown by the simulation results are in good agreement with the experimental results. The method can be applied to predict the probable defects, assess the structural properties, and optimize the processing parameters of the stretch blow molding process.

Effects of Solidification Parameters on SDAS of A357 Alloy

2008 ◽  
Vol 51 ◽  
pp. 85-92 ◽  
Author(s):  
Juan He ◽  
Jian Min Zeng ◽  
Along Yan
Keyword(s):  
Cooling Rate ◽  
Solidification Time ◽  
Local Solidification Time ◽  
A357 Alloy ◽  
Solidification Condition ◽  
Alloy Casting ◽  
Furan Resin ◽  
Solidification Parameters ◽  
Relationship Of ◽  
The Relationship

In this investigation, experiments were carried out to study the relationship of solidification parameters and the secondary dendrite arm spacing (SDAS) in A357 alloy casting with various thicknesses under the same solidification condition. The results show that the cooling rate decreases as the thickness of specimens increases, the local solidification time increased, and SDAS increased. The relationships between the SDAS and cooling rate and local solidification time under the condition of furan resin self-hardening sand casting were obtained: SDAS = 20.8 tf 0.3, SDAS = 69.34 v -0.3. The mechanical properties have some linear relations with SDAS of A357 alloy after aging heat treatment. The correlations can be expressed: UTS=410.4-0.8SDAS and El%=7.9-0.05SDAS.

Study on Ultra-Precision Ball Surface Floating Polishing Kinematics Mechanism

2006 ◽  
Vol 532-533 ◽  
pp. 109-112
Author(s):  
Xun Lv ◽  
Ju Long Yuan ◽  
Dong Hui Wen ◽  
Qian Fa Deng ◽  
Fei Yan Lou
Keyword(s):  
Chemical Conversion ◽  
Processing Parameters ◽  
Precision Machining ◽  
High Tech ◽  
National Defense ◽  
Ball Surface ◽  
Angular Velocities ◽  
Ultra Precision ◽  
Relationship Of ◽  
The Mathematical Model

The high precision balls are requested in national defense, astronautics and high-tech commercial domain urgently. Conventional precision machining methods are sensitive to uniformity of abrasives and machining environment. After precision machining, there are easily to produce thick damaged layer on the ball surface because of machining stress and chemical conversion. On the basis of the floating polishing mechanism, a new scatheless ultra-precision polishing method of ball surface can solve the problems of abrasives uniformity effectively and damaged layer. In order to ensure that the new polishing method polishes ball surface equally, the appropriate angular velocities of the ball should be selected. This paper sets up the mathematical model about the motion of ball. By analyzing and simulating the relationship of the angular velocities, the best processing parameters are acquired.

Application of Orthogonal Test in Numerical Simulation of Glass Lens Molding

2012 ◽  
Vol 497 ◽  
pp. 245-249
Author(s):  
Dao Cheng Zhang ◽  
Ke Jun Zhu ◽  
Yong Jian Zhu ◽  
Shao Hui Yin ◽  
Jian Wu Yu
Keyword(s):  
Process Parameters ◽  
Orthogonal Experiment ◽  
Fem Simulation ◽  
Orthogonal Test ◽  
Test Method ◽  
Testing Time ◽  
Molding Process ◽  
Glass Lens ◽  
Lens Molding ◽  
Process Factors

Glass lens molding is a high-volume fabrication method for producing optical components. In this paper, combined with the orthogonal test method and finite element method (FEM) simulation, the coupled thermo-mechanical analysis was carried out to analyze the key process factors. In order to reduce the testing time, an orthogonal test with three sets of level factors and three parameters is conducted to obtain the optimal molding process parameters. The result shows that the most significant parameter is molding velocity, the other effect parameters are molding temperature and friction coefficient. According to the previous analysis of orthogonal experiment, it is shown that the best optimal finishing process parameters were A2B1C1.

Affected Characteristics Analysis of the Pulsed Laser Forming of Metal Sheet

2008 ◽  
Vol 375-376 ◽  
pp. 333-337
Author(s):  
Li Jun Yang ◽  
Yang Wang
Keyword(s):  
Laser Beam ◽  
Pulsed Laser ◽  
Metal Sheet ◽  
Grain Structure ◽  
Experimental Result ◽  
Laser Forming ◽  
Forming Process ◽  
Grain Orientations ◽  
Characteristics Analysis ◽  
Relationship Of

Laser forming of metal sheet is a forming technology of sheet without a die that the sheet is deformed by internal thermal stress induced by partially irradiation of a laser beam. In this paper, the bending behavior of common stainless steel 1Cr18Ni9 sheet is studied after being irradiated by straight line with a Nd:YAG pulsed laser beam. The aim of the investigation is to find out the relationship of the physical behaviors of heat affected zone (HAZ) with the pulse parameters of the laser. Through the analysis of the fundamental theory of pulsed laser affected, this paper shows the affected characteristics of metal sheet with pulsed laser forming. The results show that the microstructure of HAZ of pulsed laser scanned is layered, and the micro-hardness is improved than that in matrix. The microstructures show that the deformed grain structure is inhomogeneous, that caused the grain sizes and grain orientations in HAZ to become different. By qualitative analysis of experimental result, the conclusion obtained may provide basis for theoretical investigation and possible industrial application of laser forming process in the future.

Optimization of built-part distortion in laser powder bed fusion processing of Inconel 718

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
You-Cheng Chang ◽  
Hong-Chuong Tran ◽  
Yu-Lung Lo
Keyword(s):  
Cooling Rate ◽  
Cantilever Beam ◽  
Laser Power ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Laser Powder Bed Fusion ◽  
Simulation Framework ◽  
Content Type ◽  
Powder Bed ◽  
Simulation Results

Purpose Laser powder bed fusion (LPBF) provides the means to produce unique components with almost no restriction on geometry in an extremely short time. However, the high-temperature gradient and high cooling rate produced during the fabrication process result in residual stress, which may prompt part warpage, cracks or even baseplate separation. Accordingly, an appropriate selection of the LPBF processing parameters is essential to ensure the quality of the built part. This study, thus, aims to develop an integrated simulation framework consisting of a single-track heat transfer model and a modified inherent shrinkage method model for predicting the curvature of an Inconel 718 cantilever beam produced using the LPBF process. Design/methodology/approach The simulation results for the curvature of the cantilever beam are calibrated via a comparison with the experimental observations. It is shown that the calibration factor required to drive the simulation results toward the experimental measurements has the same value for all settings of the laser power and scanning speed. Representative combinations of the laser power and scanning speed are, thus, chosen using the circle packing design method and supplied as inputs to the validated simulation framework to predict the corresponding cantilever beam curvature and density. The simulation results are then used to train artificial neural network models to predict the curvature and solid cooling rate of the cantilever beam for any combination of the laser power and scanning speed within the input design space. The resulting processing maps are screened in accordance with three quality criteria, namely, the part density, the radius of curvature and the solid cooling rate, to determine the optimal processing parameters for the LPBF process. Findings It is shown that the parameters lying within the optimal region of the processing map reduce the curvature of the cantilever beam by 17.9% and improve the density by as much as 99.97%. Originality/value The present study proposes a computational framework, which could find the parameters that not only yield the lowest distortion but also produce fully dense components in the LPBF process.

Relationship of DAS to cooling rate in solidified U-700 alloy

1986 ◽  
Vol 5 (12) ◽  
pp. 1273-1274 ◽  
Author(s):  
Prakash Khedkar ◽  
Philip Nash
Keyword(s):  
Cooling Rate ◽  
Relationship Of

Internal Structure Changes of Nylon 12 in Balloon Forming Process

2014 ◽  
Vol 528 ◽  
pp. 153-161
Author(s):  
Zhen Li ◽  
Li Xia Xu ◽  
Chun Lan Lu ◽  
Guo Zhu Liu ◽  
Xin Yue Li
Keyword(s):  
Raw Materials ◽  
Strain Curve ◽  
Polymeric Chain ◽  
Hydraulic Pressure ◽  
Infrared Transmission ◽  
Forming Process ◽  
Molding Process ◽  
Structure Changes ◽  
Nylon 12 ◽  
Acting Force

Medical balloon has been widely used for the treatment of cardiovascular and cerebrovascular diseases, but the theoretical studies in processing process of medical balloon have reported less in the domestic. This paper briefly introduce in the processing process of medical balloon from the nylon 12 as raw materials, through control the conditions of primary molding, secondary molding and final molding process of the operating, then investigate the stress-strain curve of each sample in the molding process by Hydraulic Pressure Tester. And further investigated the material's lattice parameter, melting point, crystallinity and the structure changes of internal groups during the molding process separately by X-ray diffraction (XRD), differential scanning caborimetry (DSC) and infrared transmission spectroscopy (FTIR) experiment. It could be founded that the acting force between the polymeric chain of nylon 12 reduced at first, so that the material has better plasticity and machinability for forming, and then the acting force of polymer chain is enhanced, so that the final balloon has higher strength and stability were discovered during the balloon forming process.

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