Dimensional accuracy and surface finish of biomedical implant fabricated as rapid investment casting for small to medium quantity production

2017 ◽  
Vol 25 ◽  
pp. 201-211 ◽  
Author(s):  
Jaspreet Singh ◽  
Rupinder Singh ◽  
Harwinder Singh
2014 ◽  
Vol 808 ◽  
pp. 89-95 ◽  
Author(s):  
Parlad Kumar ◽  
Rupinder Singh ◽  
I.P.S. Ahuja

Conventional investment casting is one of the old manufacturing processes. It involves expensive tooling for making sacrificial wax patterns to make ceramic moulds. However, with the emergence of rapid prototyping technologies, now it is possible to make and use plastic patterns instead of wax patterns along with some advantages. In this paper, plastic patterns have been prepared by using fused deposition modeling and used for investment casting process. A case study has been discussed to make a biomedical implant by the hybridization of fused deposition modeling with investment casting. Dimensional accuracy, surface finish and hardness of the casted biomedical implants have been tested and reported.


2016 ◽  
Vol 22 (3) ◽  
pp. 445-455 ◽  
Author(s):  
Sunpreet Singh ◽  
Rupinder Singh

Purpose This paper aims to investigate the dimensional accuracy of aluminium (Al) matrix composites (AMCs) prepared by using an alternative reinforced fused deposition modeling (FDM)-based sacrificial patterns in investment casting (IC) process. Further in this work, a barrel finishing (BF) process has been introduced as an intermediate step for the improvement of surface finish of sacrificial patterns and to study the effect of BF process parameters on dimensional features of the casted AMCs. In the present research, an effort has been made to ascertain the capability/producibility of the proposed route for obtaining good geometrical tolerances. Design/methodology/approach Alternative reinforced FDM filaments were developed using single screw extruder whose melt flow index was matched with the commercial acrylonitrile–butadiene–styrene filament. IC sacrificial patterns, fabricated on existing FDM system without making any change in its hardware/software, were barrel finished for improving the surface finish. The effect of FDM, BF and IC process parameters, namely, type of filament, volume of CAD-based cubical pattern, pattern density, BF time, BF media weight and numbers of IC slurry layers, was studied using Taguchi L18 OA approach. Findings Dimensional accuracy of casted AMCs developed was optimized successfully using Taguchi L18 orthogonal array. Optical microscopic analysis made on the castings highlighted the presence of Al2O3 particles which will result into the improvement of mechanical and tribological properties. International tolerance grade of cast AMCs was calculated and found acceptable as per ISO standard UNI-EN-20286-I (1995). Further, there are strong possibilities of process to be under statistical control at proposed settings. Originality/value The paper describes a new route for the development of AMC. The effect of FDM, BF and IC process parameters on dimensional accuracy of AMCs developed is also highlighted in the present research.


Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 580
Author(s):  
Francisco J. G. Silva

Though new manufacturing processes that revolutionize the landscape regarding the rapid manufacture of parts have recently emerged, the machining process remains alive and up-to-date in this context, always presenting itself as a manufacturing process with several variants and allowing for high dimensional accuracy and high levels of surface finish [...]


2019 ◽  
Vol 26 (3) ◽  
pp. 473-483
Author(s):  
Muhammad Omar Shaikh ◽  
Ching-Chia Chen ◽  
Hua-Cheng Chiang ◽  
Ji-Rong Chen ◽  
Yi-Chin Chou ◽  
...  

Purpose Using wire as feedstock has several advantages for additive manufacturing (AM) of metal components, which include high deposition rates, efficient material use and low material costs. While the feasibility of wire-feed AM has been demonstrated, the accuracy and surface finish of the produced parts is generally lower than those obtained using powder-bed/-feed AM. The purpose of this study was to develop and investigate the feasibility of a fine wire-based laser metal deposition (FW-LMD) process for producing high-precision metal components with improved resolution, dimensional accuracy and surface finish. Design/methodology/approach The proposed FW-LMD AM process uses a fine stainless steel wire with a diameter of 100 µm as the additive material and a pulsed Nd:YAG laser as the heat source. The pulsed laser beam generates a melt pool on the substrate into which the fine wire is fed, and upon moving the X–Y stage, a single-pass weld bead is created during solidification that can be laterally and vertically stacked to create a 3D metal component. Process parameters including laser power, pulse duration and stage speed were optimized for the single-pass weld bead. The effect of lateral overlap was studied to ensure low surface roughness of the first layer onto which subsequent layers can be deposited. Multi-layer deposition was also performed and the resulting cross-sectional morphology, microhardness, phase formation, grain growth and tensile strength have been investigated. Findings An optimized lateral overlap of about 60-70% results in an average surface roughness of 8-16 µm along all printed directions of the X–Y stage. The single-layer thickness and dimensional accuracy of the proposed FW-LMD process was about 40-80 µm and ±30 µm, respectively. A dense cross-sectional morphology was observed for the multilayer stacking without any visible voids, pores or defects present between the layers. X-ray diffraction confirmed a majority austenite phase with small ferrite phase formation that occurs at the junction of the vertically stacked beads, as confirmed by the electron backscatter diffraction (EBSD) analysis. Tensile tests were performed and an ultimate tensile strength of about 700-750 MPa was observed for all samples. Furthermore, multilayer printing of different shapes with improved surface finish and thin-walled and inclined metal structures with a minimum achievable resolution of about 500 µm was presented. Originality/value To the best of the authors’ knowledge, this is the first study to report a directed energy deposition process using a fine metal wire with a diameter of 100 µm and can be a possible solution to improving surface finish and reducing the “stair-stepping” effect that is generally observed for wires with a larger diameter. The AM process proposed in this study can be an attractive alternative for 3D printing of high-precision metal components and can find application for rapid prototyping in a range of industries such as medical and automotive, among others.


2016 ◽  
Vol 45 (2) ◽  
pp. 123-129 ◽  
Author(s):  
Rupinder Singh ◽  
Sunpreet Singh

High level surface finish (SF) achievement is one of the major advantages of conventional investment casting process. Not much work hitherto has been reported for modeling the SF in conventional investment casting of industrial components. In the present study application of dimensionless analysis, has been made for developing a mathematical model for SF. Three input process parameters (namely: molten metal pouring temperature (PT), slurry layer’s combination (LC) and volume/surface-area (V/A) ratio of cast components) were judicially selected to give SF as output. This study provide main effects of these input parameters on SFand shed light on the SF mechanism in conventional investment casting. The comparison of mathematical model with experimental results has been made for validation of model.


2016 ◽  
Vol 22 (1) ◽  
pp. 123-143 ◽  
Author(s):  
Sunpreet Singh ◽  
Rupinder Singh

Purpose – This paper aims to review the industrial and biomedical applications of state-of-the-art fused deposition modelling (FDM)-assisted investment casting (FDMAIC). Brief literature survey of methodologies, ideas, techniques and approaches used by various researchers is highlighted and use of hybrid feedstock filament-based pattern to produce metal matrix composite is duly discussed. Design/methodology/approach – Pattern replica required for investment casting (IC) of biomedical implant, machine parts, dentistry and other industrial components can be directly produced by using FDM process is presented. Relevant studies and examples explaining the suitability of FDMAIC for various applications are also presented. Findings – Researches to optimize the conventional IC with FDM solutions and develop new hybrid feedstock filament of FDM done by researchers worldwide are also discussed. The review highlights the benefit of FDMAIC to surgeons, engineers and manufacturing organizations. Research limitations/implications – The research related to this survey is limited to the suitability and applicability of FDMAIC. Originality/value – This review presents the information regarding potential IC application, which facilitates the society, engineers and manufacturing organizations by providing variety of components for assisting FDM. The information reported in this paper will serve doctors, researchers, organizations and academicians to explore the new options in the field of FDMAIC.


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