Experimental Study of Demolding Properties on Stereolithography Tooling

2006 ◽  
Vol 129 (4) ◽  
pp. 843-847 ◽  
Author(s):  
Chao-Chyun An ◽  
Ren-Haw Chen
Keyword(s):  
Experimental Data ◽  
Tool Life ◽  
Erosion Resistance ◽  
Close Relation ◽  
Mold Temperature ◽  
Cooling Time ◽  
Short Run ◽  
Tool Strength ◽  
Tool Damage ◽  
Test Result

Direct tooling using stereolithography (SL) photopolymer has been developed as rapid tooling for short-run injection molds. However, the tool strength, thermal conductivity, and erosion resistance of SL mold are lower than that of the conventional metal mold. Previous study has showed that the tool life was limited under 200 shots and tool damage often occurs during part ejection. In this paper, experimental data from a demolding properties test are presented and discussed. The experiments were performed using various cooling time, hold pressure, and mold temperature. The experimental data were analyzed by measuring demolding force and surface roughness to evaluate tool life and failure mechanism in order to obtain a working range for the process parameters. The test result shows that the demolding force has close relation with cooling time and mold temperature.

Rupee-Dollar Exchange Rate and Macroeconomic Fundamentals: An Empirical Analysis Using Flexible-Price Monetary Model

2011 ◽  
Vol 12 (2) ◽  
pp. 88-105
Author(s):  
C S Shylajan ◽  
Sreejesh S ◽  
Suresh K G
Keyword(s):  
Exchange Rate ◽  
Monetary Model ◽  
Macroeconomic Variables ◽  
Indian Context ◽  
Long Run ◽  
Macroeconomic Fundamentals ◽  
Short Run ◽  
Us Dollar ◽  
Casual Relationship ◽  
Test Result

This paper empirically investigates the link between Indian rupee-US dollar exchange rates and a set of macroeconomic fundamentals using flexible-price monetary model (FPMM) for the period 1996 M1 to 2010 M12. The Johanson-Juselius cointegration test result indicates the existence of long run relationship between exchange rate and the macroeconomic variables, implying the validity of FPMM model in Indian context even though there is no short run casual relationship exist in the VECM analysis.

Using Taguchi Method to Optimize Molding Process Parameters of Chair Base

2012 ◽  
Vol 271-272 ◽  
pp. 1190-1194
Author(s):  
Hsueh Lin Wu ◽  
Ya Hui Wang
Keyword(s):  
Taguchi Method ◽  
Process Parameters ◽  
Simulation Analysis ◽  
Mold Temperature ◽  
Cooling Time ◽  
Injection Time ◽  
Molding Process ◽  
Melt Temperature ◽  
Packing Pressure ◽  
Moldflow Simulation

In this study, volumetric shrinkage at ejection of the chair base in the injection process, application of the 3D CAD software pro/e to design the shape of the product, and then combines moldflow simulation analysis and Taguchi method with L25 Orthogonal Array to determine the optimal injection molding parameters combination. In the Taguchi L25 experimental design, the six controlling factors used are melt temperature, mold temperature, injection time, packing time, packing pressure and cooling time, the result of experiment revealed that the optimum combination of parameters was the A2 (melting temperature 265°C), B3 (mold temperature 40°C), C2 (injection time 1.7sec), D4 (packing pressure 95%), E5 (packing time20sec), F5 (cooling time 20sec). The results show that the combination of Taguchi method and Moldflow can not only improve the molding process parameters effectively, but also optimize the quality of the products.

Investigation of Mold Temperature Affecting on Shrinkage of Rapid Heat Cycle Molding Plastic Part

2011 ◽  
Vol 189-193 ◽  
pp. 2477-2481 ◽  
Author(s):  
Dong Lei Liu ◽  
Chang Yu Shen ◽  
Chun Tai Liu ◽  
Yong Xin ◽  
Ling Sun
Keyword(s):  
Deformation Temperature ◽  
Thermal Deformation ◽  
Injection Pressure ◽  
Mold Temperature ◽  
Cooling Time ◽  
Melt Temperature ◽  
Heat Cycle ◽  
Temperature Conditions ◽  
Packing Pressure ◽  
Packing Time

In order to further investigate the influence of mold temperature in rapid heat cycle molding on shrinkage of plastic past, a self-developed vehicle-used blue-tooth front shell high-gloss mold and an auxiliary device for controlling the mold temperature were employed in experiments. And the effect of the other parameters on shrinkage of part with fixed or changed mold temperature conditions was also studied. Results reveal that the shrinkage of RHCM part is reduced obviously compared with a conventional one, decreasing as quasi-linear with mold temperature increased gradually. At same mold temperature conditions, packing pressure, followed by packing time, is the most significant parameter on shrinkage of part, while cooling time has almost no impact on it. Melt temperature and injection pressure effecting on shrinkage of part exists a critical value, near the thermal deformation temperature of plastic. When mold temperature is set below this temperature, injection pressure has more significant than melt temperature, but it is the opposite. With being elevated gradually of mold temperature, shrinkage of part shows a slight decrease trend under same melt temperature and injecting pressure. While it fluctuates as a “V” shape with a narrow range under same packing pressure, packing time and cooling time presumed conditions, and reaches the minimum near the thermal deformation temperature of plastic.

Dynamic inter-linkage between foreign aid and economic growth in Sri Lanka

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ahamed Lebbe Mohamed Aslam ◽  
Sabraz Nawaz Samsudeen
Keyword(s):  
Economic Growth ◽  
Data Analysis ◽  
Sri Lanka ◽  
Foreign Aid ◽  
Correction Term ◽  
Causality Test ◽  
Content Type ◽  
Long Run ◽  
Short Run ◽  
Test Result

PurposeThe objective of this study is to explore the dynamic inter-linkage between foreign aid and economic growth in Sri Lanka over the period of 1960–2018.Design/methodology/approachBoth exploratory and inferential data analysis tools have been employed to examine the objective of this study. The exploratory data analysis covered the scatter plots, confidence ellipse with kernel fit. The inferential data analysis included the augmented Dickey–Fuller (ADF) and Phillips–Perron (PP) unit root tests, the autoregressive distributed lag (ARDL) Bounds co-integration technique and the Granger causality test.FindingsThe test result of exploratory data analysis indicates that there is a positive relationship between foreign aid and economic growth. The ADF and PP unit root tests results indicate that the variables used in this study are stationary at their 1st difference. The co-integration test result confirms the presence of long-run relationship between foreign aid and economic growth in Sri Lanka. The estimated coefficient of foreign aid in the long-run and the short-run shows that foreign aid has a positive relationship with economic growth in Sri Lanka. The estimated coefficient of error correction term indicates that approximately 26.6% of errors are adjusted each year and further shows that the response variable of economic growth moves towards the long-run equilibrium path. The Granger causality test result shows that foreign aid in short-run Granger causes economic growth in Sri Lanka which means that one-way causality from foreign aid to economic growth is confirmed. Further, the estimated coefficient of error correction term confirms that there is the long-run Granger causal relationship between foreign aid and economic growth in Sri Lanka.Practical implicationsThe findings of this study have some important policy implications for the design of efficient policy related to foreign aid and economic growth, the knowledge of which will help follow sustainable foreign aid and growth nexus.Originality/valueThis study contributes to the existing literature by using the newly introduced ARDL Bounds cointegration technique to investigate the dynamic inter-linkage between foreign aid and economic growth in Sri Lanka.

Bubble Dynamics for Nucleate Pool Boiling of Electrolyte Solutions

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
Seyed Ali Alavi Fazel ◽  
Seyed Baher Shafaee
Keyword(s):  
Experimental Data ◽  
Bubble Dynamics ◽  
Pool Boiling ◽  
Close Relation ◽  
Electrolyte Solutions ◽  
Nucleate Boiling ◽  
Heat Fluxes ◽  
Experimental Results ◽  
Nucleate Pool Boiling ◽  
Wide Range

Bubble dynamics is the most important subphenomenon, which basically affects the nucleate pool boiling heat transfer coefficient. Previous investigations state that the effect of physical properties of liquid and vapor phases on bubble departure diameter are often conflicting. In this article, extensive new experimental data are presented for the bubble departure diameter for various electrolyte aqueous solutions over a wide range of heat fluxes and concentrations. Experimental results show that the bubble detachment diameter increase with increasing either boiling heat flux or electrolyte concentration. Experimental results also present a close relation between the dimensionless capillary and bond numbers. A new model for the prediction of vapor bubble departure diameter in nucleate boiling for the electrolyte solutions is proposed, which predicts the experimental data with a satisfactory accuracy.

Prediction of Tool Life and Experimental Investigation during Hot Milling of AISI H13 Tool Steel

2009 ◽  
Vol 83-86 ◽  
pp. 190-197
Author(s):  
A.K.M. Nurul Amin ◽  
A.M.K. Hafiz ◽  
Mohd Amri Lajis ◽  
Anayet Ullah Patwari
Keyword(s):  
Experimental Data ◽  
Tool Life ◽  
End Milling ◽  
Experimental Investigations ◽  
Depth Of Cut ◽  
Work Piece ◽  
Aisi H13 ◽  
Steel Aisi ◽  
Rsm Model ◽  
Aisi H13 Tool Steel

This paper presents the results of experimental investigations conducted on a vertical machining centre (VMC) using spindle speed, feed rate, and depth of cut as machining variables to ascertain the effectiveness of TiAlN insert in end milling of hardened steel AISI H13, under work-piece preheated conditions and hence a statistical model was developed using the capabilities of Response Surface Methodology (RSM) to predict the tool life. Sufficient number of experiments was conducted based on the small central composite design (CCD) concept of RSM to generate tool life data for the selected machining variables. The adequacy of the model was tested at 95% confidence interval. Meanwhile, a time trend was observed in residual values between model predictions and experimental data, reflecting little deviations in tool life prediction. A very good performance of the RSM model, in terms of agreement with experimental data, was achieved. The model can be used for the analysis and prediction of the complex relationship between cutting conditions and the tool life in flat end milling of hardened materials.

scholarly journals Analysis of Influence of Spindle Speed and Feeding Speed to Tool Wear and Surface Roughness

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
D.L Zariatin
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Tool Life ◽  
Metal Cutting ◽  
Close Relation ◽  
Spindle Speed ◽  
Machining Process ◽  
Depth Of Cut ◽  
Feeding Speed ◽  
Machining Parameter

One of the problem in metal cutting is tool wear. Its close relation to the expected tool life and quality of product, make tool wear become object of investigation. Eventough tool manufacturers always give recommendation on machining parameter, but they don't share the information on tool wear estimation. Some theory on tool wear has been proposed, but still need verification thru experimental works to determine parameters and constants of tool life typical to machine tool condition and machining process. In this research, experimental work and analysis of the influence of spindle speed (n, rpm), feeding speed (Vf, mm/min) and depth of cut (ap, mm)to surface roughness and tool wear on milling process using carbide ballnose with diameter of 10 mm on Al-7075 had been conducted. From the experiment, it can be concluded that tool wear has influence on surface roughness of product. Tool wear could be minimized by choosing optimum spindle speed and feeding speed.

scholarly journals Payments and freedoms: Effects of monetary and legal incentives on COVID-19 vaccination intentions in Germany

2021 ◽  
Author(s):  
Philipp Sprengholz ◽  
Luca Henkel ◽  
Cornelia Betsch
Keyword(s):  
Experimental Data ◽  
Monetary Incentives ◽  
Negative Test ◽  
Negative Test Result ◽  
Vaccination Uptake ◽  
Percentage Points ◽  
Within Subjects ◽  
Educational Campaigns ◽  
Test Result ◽  
Implementation Challenge

Monetary and legal incentives have been proposed to promote COVID-19 vaccination uptake. To evaluate the suitability of incentives, an experiment with German participants examined the effects of payments (varied within subjects: 0 to 10,000 EUR) and freedoms (varied between subjects: vaccination leading vs. not leading to the same benefits as a negative test result) on the vaccination intentions of previously unvaccinated individuals (n = 782). While no effect could be found for freedoms, the share of participants willing to be vaccinated increased with the payment amount. However, a significant change required large rewards of 3,250 EUR or more. While monetary incentives could increase vaccination uptake by a few percentage points, the high costs of implementation challenge the efficiency of the measure and call for alternatives. As experimental data suggest that considering vaccination as safe, necessary, and prosocial increases an individual’s likelihood of wanting to get vaccinated without payment, educational campaigns should emphasize these features when promoting vaccination against COVID-19.

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