Rahul Jagtap

Bio: Rahul Jagtap is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Incremental sheet forming & Forming processes. The author has an hindex of 2, co-authored 11 publications receiving 23 citations. Previous affiliations of Rahul Jagtap include Sardar Vallabhbhai National Institute of Technology, Surat.

An experimental study on the influence of tool path, tool diameter and pitch in single point incremental forming (SPIF)

Abstract: Incremental forming process has become more and more popular because of its ease of forming and capability to produce different part shapes using same machine set-up. This article describes an experimental study on the influence of process parameters in single point incremental forming (SPIF) on the surface roughness and thickness of formed part. Experiments are performed on aluminium alloy (Al-1050) sheet on a 3-axis CNC milling machine. Hemispherical-headed tool of stainless steel (SS-304) is used to study the effect of tool path, tool diameter and pitch on the surface roughness (Ra) and thickness (t) of formed part. Design of experiment (DOE) full factorial plan is used, and results are plotted using ANOVA. Considerable effect of tool diameter is found on the surface quality of formed part.

An experimental study on geometric accuracy in hybrid incremental sheet forming

Abstract: In the present experimental study, influence of process parameters in hybrid incremental sheet forming (HISF) is studied. Stretch forming combined with ISF is used for forming of conical parts. Str...

Optimisation and modelling of thinning and geometric accuracy in incremental sheet forming combined with stretch forming

Abstract: In the present experimental study incremental sheet forming is combined with stretch forming in order to obtain uniform thickness distribution, minimise thinning and to improve geometric accuracy of formed part. Preforming or stretch forming is initially done in order to obtain initial thickness distribution. Incremental sheet forming is then employed to obtain final part shape and thickness distribution. Forming time is also minimised considerably because of initial stretch forming process. The experiments are designed using central composite design (CCD) of response surface methodology. From the results, it is observed that preforming and preform tool shape have significant influence on sheet thinning. Also the combination of ISF and stretch forming processes yields in reduced thinning and uniform thickness distribution. Multi-performance optimisation using desirability function is also performed to improve thinning and geometric accuracy. Further mathematical models are developed which are in good agreement with the experimental results.

Kerf Formation Analysis in the Abrasive Waterjet Cutting of Industrial Ceramics

Abstract: This paper investigated the machinability and kerf formation characteristics associated with the abrasive waterjet cutting of industrial ceramics. It is found that at low cutting rates, the erosive process is associated with initial surface fracture leading to a high degree of plastic flow and deformation of the subsurface, probably due to the incidence of high thermal stresses at the jet–target interaction zone. At higher speeds, surface fracture results in an intergranular network propagating downward, creating a critical shear plane that forms a kerf due to the hydrodynamic forces within the waterjet. This study reveals that there exists a combination of process parameters for the effective machining of ceramics. A grooving wear effect exists for the uncut through kerf.

Recent Developments and Trends in Sheet Metal Forming

Abstract: Sheet metal forming (SMF) is one of the most popular technologies for obtaining finished products in almost every sector of industrial production, especially in the aircraft, automotive, food and home appliance industries. Parallel to the development of new forming techniques, numerical and empirical approaches are being developed to improve existing and develop new methods of sheet metal forming. Many innovative numerical algorithms, experimental methods and theoretical contributions have recently been proposed for SMF by researchers and business research centers. These methods are mainly focused on the improvement of the formability of materials, production of complex-shaped parts with good surface quality, speeding up of the production cycle, reduction in the number of operations and the environmental performance of manufacturing. This study is intended to summarize recent development trends in both the numerical and experimental fields of conventional deep-drawing, spinning, flexible-die forming, electromagnetic forming and computer-controlled forming methods like incremental sheet forming. The review is limited to the considerable changes that have occurred in the SMF sector in the last decade, with special attention given to the 2015–2020 period. The progress observed in the last decade in the area of SMF mainly concerns the development nonconventional methods of forming difficult-to-form lightweight materials for automotive and aircraft applications. In evaluating the ecological convenience of SMF processes, the tribological aspects have also become the subject of great attention.

Emerging Trends in Single Point Incremental Sheet Forming of Lightweight Metals

Abstract: Lightweight materials, such as titanium alloys, magnesium alloys, and aluminium alloys, are characterised by unusual combinations of high strength, corrosion resistance, and low weight. However, some of the grades of these alloys exhibit poor formability at room temperature, which limits their application in sheet metal-forming processes. Lightweight materials are used extensively in the automobile and aerospace industries, leading to increasing demands for advanced forming technologies. This article presents a brief overview of state-of-the-art methods of incremental sheet forming (ISF) for lightweight materials with a special emphasis on the research published in 2015–2021. First, a review of the incremental forming method is provided. Next, the effect of the process conditions (i.e., forming tool, forming path, forming parameters) on the surface finish of drawpieces, geometric accuracy, and process formability of the sheet metals in conventional ISF and thermally-assisted ISF variants are considered. Special attention is given to a review of the effects of contact conditions between the tool and sheet metal on material deformation. The previous publications related to emerging incremental forming technologies, i.e., laser-assisted ISF, water jet ISF, electrically-assisted ISF and ultrasonic-assisted ISF, are also reviewed. The paper seeks to guide and inspire researchers by identifying the current development trends of the valuable contributions made in the field of SPIF of lightweight metallic materials.

Characterisation of geometrical and physical properties of a stainless steel denture framework manufactured by single-point incremental forming

Abstract: In recent years, numerous scientific and technological innovations have been introduced in the fields of medicine and dentistry. The application of computer-based engineering techniques has enabled significant improvement in the design and performance of biomedical components, including implants and prostheses. Innovative and flexible manufacturing methods, such as single point incremental forming (SPIF), allow the cost-effective production of these “custom-made” components. The SPIF technology has been employed to manufacture a metal denture base plate (framework) of a complete maxillary (upper) denture to replace a traditional prosthodontic procedure based on a lost-wax technique, which is time-consuming and requires much manual work. Stainless steel sheet of quality X6Cr17 and thickness of 0.5 mm was adopted due to its biocompatibility, good mechanical properties, and reasonable price. The SPIF process was completely designed in a digital environment with a focus on achieving high quality and accuracy of the part followed by experimental verification. For validation, the formed part was compared in terms of the geometry and mechanical strength with the reference one fabricated using the lost-wax technique. The results obtained confirmed the high dimensional accuracy and good strength of the SPIF-made part. The experimental investigations also included analysis of sheet thinning, surface roughness, and microstructure.

Surface Finish Analysis in Single Point Incremental Sheet Forming of Rib-Stiffened 2024-T3 and 7075-T6 Alclad Aluminium Alloy Panels

Abstract: The article presents the results of the analysis of the interactions between the single point incremental forming (SPIF) process parameters and the main roughness parameters of stiffened ribs fabricated in Alclad aluminium alloy panels. EN AW-7075-T6 and EN AW-2024-T3 Alclad aluminium alloy sheets were used as the research material. Panels with longitudinal ribs were produced with different values of incremental vertical step size and tool rotational speed. Alclad is formed of high-purity aluminium surface layers metallurgically bonded to aluminium alloy core material. The quality of the surface roughness and unbroken Alclad are key problems in SPIF of Alclad sheets destined for aerospace applications. The interactions between the SPIF process parameters and the main roughness parameters of the stiffened ribs were determined. The influence of forming parameters on average roughness Sa and the 10-point peak–valley surface roughness Sz was determined using artificial neural networks. The greater the value of the incremental vertical step size, the more prominent the ridges found in the inner surface of stiffened ribs, especially in the case of both Alclad aluminium alloy sheets. The predictive models of ANNs for the Sa and the Sz were characterised by performance measures with R2 values lying between 0.657 and 0.979. A different character of change in surface roughness was found for sheets covered with and not covered with a soft layer of technically pure aluminium. In the case of Alclad sheets, increasing the value of the incremental vertical step size increases the value of the surface roughness parameters Sa and Sz. In the case of the sheets not covered by Alclad, reduction of the tool rotational speed increases the Sz parameter and decreases the Sa parameter. An obvious increase in the Sz parameter was observed with an increase in the incremental vertical step size.