Sunpreet Singh

Fused deposition modelling based rapid patterns for investment casting applications: a review

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/...

Development of ABS based wire as feedstock filament of FDM for industrial applications

Purpose n n n n nAcrylonitrile-butadiene-styrene (ABS)-based plastic is one of the most widely used filament materials for fused deposition modelling (FDM) applications. Because the FDM system, as well as its filament material (ABS), has been patented by commercial manufacturers, the cost of the filament material is significantly high, which affects the commercialization of this technology for medium- and small-scale industries. This problem may be addressed by developing alternative FDM filament material at the user end. The present research work aims to make an effort to develop cost-effective ABS filament with acceptable mechanical properties at par with the filament prepared by commercial manufacturers. Further, mathematical models have been developed for optimizing mechanical properties (like: tensile strength, Young’s modulus and dimensional accuracy) of in-house-fabricated filament. n n n n nDesign/methodology/approach n n n n nThe processing parameters (such as barrel temperature, screw speed and take-up speed) of single-screw extruder used to fabricate ABS filament have been studied and optimized. n n n n nFindings n n n n nAlthough the mechanical properties of fabricated ABS filament were not better than those of the original equipment manufacturer (OEM) filament, yet significant cost reduction was achieved with in-house fabrication. Mechanical properties like tensile strength, Young’s modulus and dimensional accuracy have been optimized using response surface methodology (RSM) for acceptability of in-house-fabricated filament (for commercial applications) at par with the OEM filament. n n n n nOriginality/value n n n n nThis paper highlights the systematic steps for in-house fabrication of cost-effective FDM filament. Further, RSM-based mathematical models have been developed for optimizing mechanical properties of newly fabricated filament.

Effect of Process Parameters on Hardness of Hip Joint Developed by Combining Fused Deposition Modelling and Investment Casting

Fused deposition modelling (FDM) is one of the commonly used processes, which read data from CAD drawing and generate 3-D objects layer-by-layer. In the present research work, biomedical implant (hip joint) has been developed by combination of two processes; FDM and investment casting (IC). Three controllable factors of the IC process (namely: number of layer, clay viscosity, dry time of primary coating) were studied at three levels each by Taguchi’s parametric approach and single-response optimization was conducted to identify the main factors controlling hardness of cast specimen. The master patterns of hip joint were of Acrylonitrile-Butadiene-Styrene (ABS) material (prepared with FDM process) and final cast specimens of stainless steel (SS-316L) were made through ceramic shell IC at recommended parameters. The results of study suggests that for hardness, contribution of number of layers, viscosity of primary dip and dry time of primary coating is 16.17, 65.8 and 13.63xa0% respectively. Further surface morphology has been used to analyze the hardness data.

Investigations for dimensional accuracy of AMC prepared by using Nylon6-Al-Al2O3 reinforced FDM filament in investment casting

Purpose n n n n nThis 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. n n n n nDesign/methodology/approach n n n n nAlternative 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. n n n n nFindings n n n n nDimensional 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. n n n n nOriginality/value n n n n nThe 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.

Dimensionless analysis for obtaining desired surface finish of plastic replicas prepared by hybrid moulds

Hybrid moulding (HM) is one of the recent advancements in the mould-making process, especially for preparing replicas of plastic components with tailor-made properties. This study highlights the development of a mathematical model (based upon dimensionless analysis) for obtaining the desired surface finish (SF)/Ra of a chip-set case prepared by HM. The input process parameters of HM, namely, de-mould temperature, harder: softener mixing ratio, and type of material have been judiciously selected for understanding the mechanism of Ra in HM. This study highlights the main effects of these input process parameters on SF/Ra as mathematical models.

Surgical Support and Modeling Tools, Materials, and Their Processing Technologies

Due to the increase in the number of older individuals, road accidents, birth deformities, terrorist attacks, poor nutrition, and unfriendly environments, there is a high demand for artificial limbs/implants. Fortunately, we have reached a new era of technological advancements, with scientific/medical improvements in various existing approaches and newly developed approaches that have contributed to the field of medicine. Emerging surgical tools in the form of three-dimensional printing (3DP), image/data processing software, and combinations thereof for presurgical planning, surgical guides, surgical kits, implant fabrication, and implant placement have reduced the efforts of surgeons. The present article discusses some of the critical and complex surgical applications of 3DP technologies, their procedures, and their efficacy.

Investigating the friction coefficient in functionally graded rapid prototyping of Al–Al2O3 composite prepared by fused deposition modelling

Purpose n n n n nThe present research work aims to study the friction coefficient in functionally graded rapid prototyping of Al–Al2O3 composite prepared via fused deposition modelling (FDM)-assisted investment casting (IC) process. The optimized settings of the process parameters (namely, filament proportion, volume of FDM pattern, density of FDM pattern, barrel finishing (BF) time, BF media weight and number of IC slurry layers) suggested in the present research work will help fabricate parts possessing higher frictional coefficient. n n n n nDesign/methodology/approach n n n n nInitially, melt flow index (MFI) of two different proportions of Nylon6-Al–Al2O3 (to be used as an alternative FDM filament material) was tested on the melt flow indexer and matched with MFI of commercially used acrylonitrile–butadiene–styrene filament. After this, the selected proportions of Nylon6-Al–Al2O3 were prepared in the form of the FDM filament by using a single screw extruder. Further, this FDM filament has been used for developing sacrificial IC patterns in the existing FDM system which was barely finished to improve their surface finish. Castings developed were tested for their wear resistance properties on a pin-on-disc-type tribo-tester under dry conditions at sliding conditions to check their suitability as a frictional device for industrial applications. In the methodology part, Taguchi L18 orthogonal array was used to study the effect of selected process variables on the coefficient of friction (μ). n n n n nFindings n n n n nIt has been found that filament proportion, volume of FDM pattern and density of FDM pattern have significantly affected the μ-values. Further, density of the FDM pattern was found to have 91.62 per cent contribution in obtaining μ-values. Scanning electron micrographs highlighted uniform distribution of Al2O3 particles in the Al-matrix at suggested optimized settings. n n n n nPractical implications n n n n nThe present methodology shows the development of a functional graded material that consisted of surface reinforcement with Al2O3 particles, which could have applications for manufacturing friction surfaces such as clutch plates, brake drum, etc. n n n n nOriginality/value n n n n nThis paper describes the effect of process parameters on wear properties of the Al–Al2O3 composite developed as a functionally graded material by the FDM-based pattern in the IC process.

Polymer Twin Screw Extrusion With Filler Powder Reinforcement

The extrusion of material is one of the established manufacturing process used for reshaping, mixing, and also for enhancing the mechanical/metallurgical properties of the final products. Nowadays, tasks like compounding/blending of suitable proportions of different ingredients are being practiced in the area of pharmaceuticals, polymer technology, food processing, bioprocessing and technology, etc. The literature review highlighted that the quality of the product is highly dependent on the process variable of compounder/blenders, commonly termed as twin screw extruders (TSEs). The present chapter aims to review the effect of twin screw extruder parameters on the filler powder (like ceramics) reinforced polymer material-based product and their quality characteristics. Further, lab experiments have been conducted to counter check the reviewed parameters on the mechanical, rheological, and thermal properties of ceramic reinforced polymeric blend-based composite filament wires. Statistical analysis of variance has also been performed to check the significance and contribution of input variables.

Investment Casting (Disposable Mold)

In this article, various research possibilities to improve the investment cast mold’s characteristics have been outlined for field applications. The reported literature highlights that various input parameters like ingredients of the molding sand, dry strength, collapsibility, cavity precision, surface finish, and heat transfer rate are some of the significant parameters for controlling the mechanical/metallurgical properties of final cast component. The inclusion of organic and inorganic fibers can further enhance the strength and dimensional stability along with reduction in the cost and time associated with the fabrication. Furthermore, with the invention of additive manufacturing technologies it is now possible to create a customized cavity directly from the computer-aided design file, through a series of established process especially for batch production activities.

Integration of Fused Deposition Modeling and Vapor Smoothing for Biomedical Applications

Fused deposition modeling (FDM), a process for the fabrication of customized polymer/plastic parts, has been recognized as one of the most economical additive manufacturing technologies. Since its development in the late 19th century, the slow but gradual innovations in this technology have made it suitable for wide range of engineering and scientific applications, biomedical as the most emerging. However, due to the physics of processing, it is not possible to avoid the poor geometrical textures resulting due to staircase stepping, without carrying out posttreatments. Reportedly, chemical treatment of the resulting FDM surfaces is best apposite with negligible conflict with the geometrical features. In the literature, various attempts have been made to study the effect of various process parameters on the resulting output properties of biomedical implant (namely, hip joints), to be used further for the investment casting (IC) process. This chapter attempts to critically discuss the case studies in order to provide a clear picture of the various steps involved in combined FDM and vapor smoothing process, along with the effect of vapor smoothing process parameters on quality characteristics of resulting implants. Overall, the content of this chapter is structured in a way to provide the important necessary detail to the field engineers working in this area.