Manufacturing Technology Today

Y. Ravi Kumar ¹, C. S. P. Rao ¹, T. A. Janardhan Reddy ²

Affiliations
1 Dept. of Mechanical Engg., National Institute of Technology, Warangal, IN
2 Dept. of Mechanical Engg., University College of Engg., Osmania University, Hyderabad, IN

Abstract

Rapid prototyping (RP) technique has come to stay as one of the promising techniques for cutting down product development time by way of realizing a touch and feel prototype or a prototypecomponent that can be directly used in assemblies, product testing, or tooling for short or medium run production. Selective Laser Sintering (SLS) is a leading process for developing rapid prototype objects by selectively fusing layers of powder according to numerically defined cross sectional geometry. The parts produced by SLS have lower strength than the parts produced by conventional techniques like injection moulding. The part strength is affected by the various process parameters used in SLS process. Three parameters, namely, laser power, scan spacing and part orientation were identified and the range of the parameters for the present investigation. In the present work an attempt has been made to study the affect of these parameters on part strength. Taguchi method of experimental design is used to plan the experiments. The experiments were conducted by using DuraForm PA (polyamide) powder on a DTM Sinter station 2500^plus SLS rapid prototyping machine. The experimental results are summarized by using the analysis of variance (ANOVA) method where significant main factors and their interactions are identified. The relationship plots between the part strength and process parameters are obtained by using MATLAB 6.0 software. This paper gives the results of the study and the conclusions drawn from it.

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P. V. R. Ravindra Reddy ¹, Chandra Mohan Reddy ², T. A. Janardhan Reddy ³

Affiliations
1 CBIT, Gandipet, Hyderabad, IN
2 Dept. of Mech. Engg, CBIT, Gandipet, Hyderabad, IN
3 Dept. of Mech. Engg, O.U College of Engg., Hyderabad, IN

Abstract

Deep drawing is a complex process that is influenced by various parameters like tooling configurations, blank configurations, material properties, and forming conditions. Limit Drawing Ratio is one of the parameters that indicate the drawability of material. There is lot of research on the effect of material parameters on LDR, but a little work is done on tooling and process parameters. In this paper, the effect of various tooling and process parameters like die profile, punch profile, clearance, friction factor, punch diameter on limit drawing ratio is investigated and presented using an explicit finite element code LSDYNA 3D. The model is validated by comparing force obtained in experiment with the one obtained in simulation. A screening test is conducted to fin d out the most infuencing parameters and their interactions using L8 orthogonal array. Column effect method and plotting method are used for the analysis. After identifying the most effective parameters , their affect on the LDR is studied and presented in the paper.

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Y. Ravi Kumar ¹, C. S. P. Rao ², T. A. Janardhan Reddy ³, P. Radhakrishnan ⁴

Affiliations
1 Department of Production Engineering, V.R Siddhartha Engineering College, Vijayawada - 520 007, IN
2 Department of Mechanical Engineering, National Institute of Technology, Warangal - 506 004, IN
3 Department of Mechanical Engineering, University College of Engineering, Osmania University, Hyderabad - 500 007, IN
4 Vellore Institute of Technology, Vellore - 632 014, IN

Abstract

Rapid prototyping (RP) plays a key role in development of prototypes to serve as a design visualization tool as well as in functional areas of manufacturing to speed up the product development lead-time. Fused deposition modeling (FDM) is the one of the key technologies of rapid prototyping. The prototype quality is affected by the various process parameters used in FDM process. This paper describes the Taguchi method based robust design philosophy for minimization of form errors in fused deposition modeling. Four parameters, namely, layer thickness, road v\/idth, air gap, and speed were identified and the range of the parameters for the present investigation was determined from preliminary experiments. Each parameter was investigated at three levels to study the non-linearity effect of the parameters. Taguchi method based Lg orthogonal array was selected and experiments were conducted as per experimental layout plan. This paper gives the results of the study and the conclusions drawn from it.

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