Sachin Waigaonkar

A New Approach for Resin Selection in Rotational Molding

The problem of resin selection for a rotational molding process has been a concern for the molder considering the availability of a number of resins with different properties. In this article, we have explored a multiple attribute-based decision making (MADM) selection procedure based on the technique of order preference by similarity to ideal solution (TOPSIS). The procedure has been adapted to rank the different resins, to quantitatively assist a rotomolder to select a proper resin from a long list for a specific application. A case study of material selection for a rotationally-molded automotive fuel tank is used to explain the intricacies involved. The selection is also compared with other graphical methods of decision making.

Biocompatible agarose-chitosan coated silver nanoparticle composite for soft tissue engineering applications.

Abstract With increasing gap in the demand and supply of vital organs for transplantation there is a pressing need to bridge the gap with substitutes. One way to make substitutes is by tissue engineering which involves combining several types of synthetic or biomaterials, cells and growth factors cross-linked together to synthesize a functional scaffold for repair or replacement of non-functional organs. Nanoparticle based composites are gaining importance in tissue engineering due to their ability to enhance cell attachment and proliferation. The current study focuses on synthesizing agarose composites embedded with chitosan-coated silver nanoparticles using glutaraldehyde as the cross-linker. The synthesis of chitosan coated silver nanoparticles within the scaffold was confirmed with UV-visible spectroscopy. Physical and chemical characterization of the synthesized nanoparticles were done by XRD, FTIR, TGA and SEM. DMA showed higher mechanical strength of the scaffolds. The scaffolds showed degradation of ∼37% within a span of four weeks. The higher physical support provided by the synthesized scaffolds was shown by in-vitro cell viability assay. Broad spectrum anti-bacterial activity and superior hemocompatibility further showed the advantage it offered for growing cells. Thus a biopolymer based nanocomposite was synthesized, with intended widespread use as scaffold for engineering of soft tissues due to its enhanced biocompatibility and greater surface area for cell growth.

Experimental investigations and optimization of processibility of sheet moulding compound

Abstract Sheet moulding compound (SMC) is a combination of glass fibers and filled polyester resin. It is processed by a compression moulding process and finds extensive applications in structural, automotive, electrical and electronic industries. The compression moulding process is characterized by the flow behavior of SMC under heat and pressure in the press mould. This paper is focused on the prediction of ideal processibility conditions of SMC. The qualitative aspect of a properly thickened (matured) moulding compound could be seen from its tack-free nature, which was quantitatively calibrated in terms of penetration depth, measured by a specially constructed softness indicator. The weight (wt)% of calcium carbonate (CaCO3) as filler, magnesium oxide (MgO) as thickener, graphite (C) and zinc stearate [Zn (C18H35O2)2] (ZnSt) as lubricants along with the maturation time (Tm) were selected as process variables. Taguchi’s scheme of experimental design was adapted to perform the experiments. It was found that the higher levels of MgO and CaCO3 were favorable for a good penetration depth as well as a reduced maturation time. We have also found that a penetration depth of at least 5 mm was required for achieving good processability conditions of SMC. An optimization study was under taken to find the right blend of additives and fillers, at their minimal weights and in the least possible maturation time, to achieve the desired processability. This study is particularly useful in a production run to make moulded parts from SMC.

Organization of Visual Inspection and Its Impact on the Effectiveness of Inspection

The research presented in this paper was aimed to analyse and evaluate the impact of organizational factors on the effectiveness of visual inspection in the manufacturing of electronic systems for the automotive industry. The study was carried out according to the authors’ own methodology consisting of three stages: detailed description of the process, developing a study plan and analysis of the results. The experiment was conducted and influence of three factors: type of inspection, shift and type of defect, was taken into consideration and evaluated. Recommendations were made to improve the quality of such inspections that will lead to the improvement in the final quality of the product.

Mechanical properties, biological behaviour and drug release capability of nano TiO2-HAp-Alginate composite scaffolds for potential application as bone implant material.

Nanocomposite scaffolds of TiO2 and hydroxyapatite nanoparticles with alginate as the binding agent were fabricated using the freeze drying technique. TiO2, hydroxyapatite and alginate were used in the ratio of 1:1:4. The scaffolds were characterized using X-ray diffraction, fourier transform infrared spectroscopy, and scanning electron microscopy. The biocompatibility of the scaffolds was evaluated using cell adhesion and MTT assay on osteosarcoma (MG-63) cells. Scanning electron microscopy analysis revealed that cells adhered to the surface of the scaffolds with good spreading. The mechanical properties of the scaffolds were investigated using dynamic mechanical analysis. The swelling ability, porosity, in vitro degradation, and biomineralization of the scaffolds were also evaluated. The results indicated controlled swelling, limited degradation, and enhanced biomineralization. Further, drug delivery studies of the scaffolds using the chemotherapeutic drug methotrexate exhibited an ideal drug release profile. These scaffolds are proposed as potential candidates for bone tissue engineering and drug delivery applications.

Improvement of Acceptance Sampling Inspection for the Operation of Sealing Packages

One of the many purposes for which data are gathered from manufacturing processes is assessment of these processes against predefined criteria. Assessment results are often used for monitoring and supervising the process based on a developed statistical model. This paper looks at the issue of selection of sample size for sampling inspection in the process of packaging medical products. Packaging is an important stage of manufacturing medical products, since the package ensures safety and sterility of the product. In the process of packaging medical products, the operation of sealing the package is of key importance in terms of following medical procedures. Tensile strength of the seal is the critical feature. This paper presents a case study in which an efficient statistical sampling plan was executed for the process of sealing medical packages which led to the saving of time as well as cost.

Effect of Different Electrolytes on Material Removal Rate, Diameter of Hole, and Spark in Electrochemical Discharge Machining

Advanced materials like glass, quartz, and composites have high potential for their applications in different fields of engineering due to their favorable properties like hardness, chemical inertness, electrical insulation, low thermal conductivity. The recent analytical and experimental work have opened the avenue of machining nonconductive materials like glass, alumina, etc., using an integrated process of electrochemical discharge machining (ECDM). ECDM is a nonconventional machining process which is an integrated process of electrochemical machining (ECM) and electro discharge machining (EDM). In this paper, ECDM has been investigated for drilling operation in glass. This study reports effect of different electrolytes on material removal rate, entrance and exit diameter of the hole, and sparking difference at the machining junction. Three different electrolytic solutions (NaOH, NaNO3, and H2SO4) have been used for ECDM. The performance of three different electrolyte solutions is compared among themselves based on the process performance based on above parameters. The conditions for the maximum material removal rate, less difference in entrance and exit diameter with better sparking stability have been established from the experimental findings.