Modeling of Dimensional Accuracy in Three Dimensional Printing for Light Alloy Casting

2014 ◽  
Vol 808 ◽  
pp. 65-78
Author(s):  
Rajesh Kumar ◽  
Rupinder Singh ◽  
Inderpreet Singh Ahuja

The purpose of this paper is to develop mathematical model to investigate the influence of shell casting parameters. Three input parameters such as shell wall thickness (SWT), Pouring temperature (PT) and weight density (WD) were selected to give output in the form of average outer diameter (AOD) as dimensional accuracy. After identification of component, technological prototypes were produced. In this work three dimensional printing (3DP) has been used as rapid shell casting to make shell mould by using Zcast 501 powder with different shell wall thickness for six different light alloy materials. Measurements on a coordinate-measuring machine helped in calculating the dimensional tolerances of the castings produced. For obtaining tight casting tolerances the dimensional accuracy of component is the most important element. The thickness, curing time and orientation of the shell molds, play an important role in providing a high quality of the cast part in time. The dimensional accuracy was found to be more in the case of maximum layer thickness and horizontal position of the component. The investigation has led to conclusions as the Quadratic models were developed for the response. The F - value is 23.93, which implies that the model as well as lack of fit is significant. The value of Prob > F is less then the standard value 0.05, which indicates model terms are significant. With the help of Post curing, shell Mold temperature was not found to affect the dimensional accuracy of the castings, significantly. It was observed that high pouring temperatures also produced castings with better dimensional accuracy. This study will provide main effect of the inputs on average outer diameter as dimensional accuracy in three dimensional printing of light alloys castings. Statistically in this case B, C, A2, B2, C2, AB, BC is the model terms which contributes significantly to the model developed for dimensional accuracy.

Author(s):  
J P Singh ◽  
R Singh

The purpose of the present investigation is to study the feasibility of decreasing the shell thickness for a statistically controlled rapid casting solution of lead alloy using three-dimensional printing technology. Starting from the identification of a component/benchmark, technological prototypes were produced with different shell thickness. Measurements on a coordinate measuring machine helped in calculating the dimensional tolerances of the castings produced. Some important mechanical properties were also compared to verify the suitability of the castings and further results are supported by microstructure analysis. The study suggested that the shell thickness having a value less than the recommended one is more suitable from a dimensional accuracy and an economic point of view. The provided data from the experimentation are extremely useful for the industrial application of the considered technology. The result indicates that at 1 mm shell thickness, the hardness of the casting improves from the recommended 12 mm. Further, production costs and production time have been reduced by 45.75 and 43 per cent, respectively, in comparison with the 12 mm recommended shell thickness.


Author(s):  
M Kaplas ◽  
R Singh

The purpose of this study is to verify the feasibility of decreasing the shell thickness in rapid casting (RC) process based on three-dimensional printing technology and to evaluate the dimensional accuracy, mechanical properties of RC solutions for the production of zinc-alloy casting. Starting from the identification of component/benchmark, technological prototypes were produced with different shell thickness. Measurements on a coordinate-measuring machine helped in calculating the dimensional tolerances of the castings produced. Some important mechanical properties were also compared to verify the suitability of the castings, and further results are supported by the radiography analysis. The study suggested that the shell thickness having value less than the recommended one is more suitable from dimensional accuracy and economic point of view. The provided data from the experimentation are extremely useful for the industrial application of the considered technology. The result indicates that at 7 mm shell thickness, hardness of the casting improved from the recommended 12 mm. Further, production cost and production time have been reduced by 41 and 37 per cent, respectively, in comparison with the 12 mm recommended shell thickness.


2011 ◽  
Vol 110-116 ◽  
pp. 653-659
Author(s):  
Rupinder Singh

In this work comparison of hybrid rapid moulds (prepared with three dimensional printing shells supported with dry, green and molasses sand) have been made for techno-economic analysis, for zinc (Zn) alloy shell casting. The comparison has been made on the basis of mechanical properties and dimensional accuracy. Time-temperature curves have been drawn to understand solidification of molten Zn alloy in hybrid moulds of different thicknesses. The results of study suggest that it is feasible to reduce shell wall thickness of hybrid mould cavity from recommended 12mm to 1mm. All castings prepared are consistent with the permissible range of IT grades and are acceptable as per ISO standard UNI EN 20286-1 (1995). Further green sand based hybrid prototypes at 3mm shell wall thickness, shows better dimensional accuracy and mechanical properties.


2016 ◽  
Vol 22 (3) ◽  
pp. 474-486 ◽  
Author(s):  
Rajesh Kumar ◽  
Rupinder Singh ◽  
IPS Ahuja

Purpose The purpose of this paper is to investigate the process capability of three-dimensional printing (3DP)-based casting solutions for non-ferrous alloy (NFA) components. Design/methodology/approach After selection and design of benchmark, prototypes for six different NFA materials were prepared by using 3DP (ZCast process)-based shell moulds. Coordinate measuring machine has been used for calculating the dimensional tolerances of the NFA components. Consistency with the tolerance grades of the castings has been checked as per IT grades. Findings The results of process capability investigation highlight that the 3DP process as a casting solution for NFA component lies in ±5sigma (s) limit, as regards to dimensional accuracy is concerned. Further, this process ensures rapid production of pre-series industrial prototypes for NFA. Final components prepared are also acceptable as per ISO standard UNI EN 20,286-I (1995). Originality/value This research work presents capability of the 3DP process supported with experimental data on basis of various process parameters for the tolerance grade of NFA castings. These statistics can help to enhance the application of 3DP-based NFA casting process in commercial foundry industry.


Author(s):  
R Singh ◽  
J P Singh

The purpose of the present investigation is to study and compare the feasibility of decreasing the shell wall thickness for rapid casting solution of brass and lead alloys using three-dimensional printing (3DP) technology. Starting from the identification of components/benchmarks, technological prototypes have been produced at different shell thicknesses using lead and brass alloys. Measurements on a coordinate measuring machine helped in calculating the dimensional tolerances of the castings produced. Some important mechanical properties are also compared to verify the suitability of the castings and further results are supported by microstructure analysis. The study suggested that the production of sound casting for minimum wall thickness depends on pouring temperature and weight density. It has been observed that IT grades comparable to machining can be obtained with 3DP for lower pouring temperature alloys. Further feasibility of obtaining minimum shell thickness is more dependent on pouring temperature than weight density. Based on improved dimensional accuracy and microstructure analysis, the saving of costs up to 45.75 per cent and time up to 43 per cent can be achieved over the recommended one in the case of lead alloy for the selected benchmark/component. For brass alloy casting saving of costs and time up to 40.05 and 32.84 per cent, respectively, has been achieved.


2021 ◽  
pp. 009524432110472
Author(s):  
Ans Al Rashid ◽  
Sikandar Abdul Qadir ◽  
Muammer Koç

Fused Filament Fabrication (FFF) has been the most widely used three-dimensional printing (3DP) technology due to its cost-effectiveness, easy application, and material readiness. FFF, to date, has been used to fabricate polymer components for rapid prototyping and increasingly for some end-user applications. Thus, there is a pressing need to optimize 3DP process parameters for FFF materials to achieve higher dimensional accuracy, especially in functional components for final use applications. Therefore, to ensure desired geometries with reasonable accuracy, precise measurements are required to validate the FFF process’s dimensional capability under different process conditions. This study presents the dimensional measurement and statistical analysis to evaluate the effect of printing materials, speed, and layer heights on dimensional accuracy and repeatability of the commercial FFF process. A benchmark part model was designed with different external and internal features commonly used in manufacturing processes. Taguchi’s design of experiments (DOE) was employed to obtain the experiments scheme, followed by the 3DP, dimensional measurement, and analysis of 3DP samples. Results revealed polylactic acid (PLA) material provided better dimensional control in most of the features. Higher printing speeds and layer heights were found optimum for external features/protrusions, whereas lower-to-medium speeds and layer heights were more appropriate for the fabrication of internal features.


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