https://i-scholar.in/index.php/MTT/issue/feed Manufacturing Technology Today 2023-09-04T14:30:26+00:00 Dr. Nagahanumaiah mtt.cmti@nic.in Open Journal Systems Manufacturing Technology Today is a monthly publication brought out by CMTI which features Technical articles on various topics like Metal working, Manufacturing, Precision Engineering, Robotics, Nano technology, etc.; Technology trends; Abstracts of literature published in journals received by CMTI library (Manufacturing Technology abstracts); Abstracts of patents granted / filed in topics related to manufacturing (Patent abstracts); Happenings within CMTI, Events related to manufacturing technology such as Seminars, Exhibitions, Conferences, etc.; News related to Intellectual property and patenting. The monthly journal could be availed from CMTI through subscription. https://i-scholar.in/index.php/MTT/article/view/223384 Thermal Error Modeling of Machine Tool Spindle Through an Ensemble Approach 2023-09-04T14:30:25+00:00 Anirban Tudu me17d021@smail.iitm.ac.in Rupavath Manikanta rupavathmanikanta@gmail.com D. S. Srinivasu devadula@iitm.ac.in <div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>Thermal error compensation of machine tool is cost-effective than other methods. Towards this, data-driven machine learning (ML) algorithms have been used to produce accurate prediction models. However, ML models have limitations, such as overfitting, requiring a large data etc. In present work, a hybrid model is proposed by exploiting the linear regression (LR), support vector machine (SVM), neural network (NN), and decision tree (DT) models. For this purpose, the optimum weights to each constituent model is identified by cosine similarity maximization. The developed models are validated against the experimental data. The prediction results with optimized weight are compared with equal weights and the root means square error (RMSE) for both methods are 1.8879 and 2.8978, respectively. The RMSE shows that the hybrid model produces good accuracy for both small and large data sets compared to individual models. </span></p></div></div></div> 2023-02-01T00:00:00+00:00 https://i-scholar.in/index.php/MTT/article/view/223385 Learning Machining Stability Using a Bayesian Model 2023-09-04T14:30:25+00:00 Advait Pujari advait.pujari767@gmail.com Harsh Singh Rajput rajharsh@iitk.ac.in) Mohit Law mlaw@iitk.ac.in Manjesh K. Singh manjesh@iitk.ac.in <div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>Instabilities in machining can be detrimental. Usually, analytical model-predicted stability charts guide selection of cutting parameters to ensure stable processes. However, since inputs to the model seldom account for the speed-dependent behaviour of the cutting process or the dynamics, models often fail to guide stable cutting parameter selection in real industrial settings. To address this issue, this paper discusses how real experimentally classified stable and unstable cutting data with all its vagaries and uncertainties can instead be used to learn the stability behaviour using a supervised Bayes' learning approach. We expand previously published work to systematically characterize how probability distributions, training data size, and thresholding influence the learning capacity of the Bayesian approach. Prediction accuracies of up to 95% are shown to be possible. We also show how the approach nicely extends itself to a continuous learning process. Results can hence inform further development towards self-optimizing and autonomous machining systems. </span></p></div></div></div> 2023-02-01T00:00:00+00:00 https://i-scholar.in/index.php/MTT/article/view/223386 Recovering Cutting Tool Modal Parameters From Randomly Sampled Signals Using Compressed Sensing 2023-09-04T14:30:25+00:00 Harsh Singh Rajput rajharsh@iitk.ac.in Mohit Law mlaw@iitk.ac.in <div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>A change in the modal parameters of cutting tools could signal tool wear, tool breakage, or other instabilities. The cutting process must be continuously monitored using vibration signals to detect such changes. Since tools vibrate with frequencies of up to a few kHz, continuous monitoring requires sampling at rates of tens of kHz to respect the Nyquist limit. Processing and storing such large data for decision making is cumbersome. To address this issue, this paper discusses the use of a compressed sensing framework that enables non-uniform random sampling at rates below the Nyquist limit. For cutting tools, we show for the first time using synthesized data that it is possible to reconstruct original signals from as few as 1% of the original data. We numerically test the method to characterize the influence of damping, noise, and multiple modes. Recovered modal parameters from the reconstructed signal agree with signals sampled properly. </span></p></div></div></div> 2023-02-01T00:00:00+00:00 https://i-scholar.in/index.php/MTT/article/view/223387 Machine Tool Multibody Dynamic Model Updating Using Vision-Based Modal Analysis 2023-09-04T14:30:26+00:00 Vishal Singh vishal.me14@gmail.com Mohit Law mlaw@iitk.ac.in <div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>Machine tool dynamic behaviour is influenced by the structural properties of its subsystems assembled at interfaces as well as by the interface characteristics. Interfaces are commonly modelled as spring-damper connections, parameters of which are usually updated by minimizing the difference between model-predicted and measured dynamics characterized by frequency response functions. This model updating approach requires global mode shapes to be measured by roving the hammer and/or the sensor such as to localize the joint parameters to be updated. Such measurements are time consuming and fraught with errors. As a new, alternative, and simpler way to update joint parameters of a machine tool multibody dynamic model, this paper reports on the use of full-field vision-based modal analysis methods. Mode shapes thus identified agree with those estimated with the traditional experimental modal analysis procedures. The updated machine tool multibody dynamic model is a step towards realizing an accurate digital twin. </span></p></div></div></div> 2023-02-01T00:00:00+00:00 https://i-scholar.in/index.php/MTT/article/view/223388 Learning Machining Stability Diagrams From Data Using Neural Networks 2023-09-04T14:30:26+00:00 Namras Amakkattil Shanavas namras0719@gmail.com Mohit Law mlaw@iitk.ac.in Manjesh K. Singh manjesh@iitk.ac.in <div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>Machining instabilities are detrimental. model predicted stability charts help identify cutting parameters for stability. Since models disregard speed-varying cutting force characteristics and dynamics, charts fail to guide stable cutting in industrial praxis. This study shows how supervised neural networks can learn stability charts from data. The learning capacity of this machine learning model depends on the size of the training dataset, its train-test split, the learning rate, the activation function, the number of hidden layers, and the number of neurons in each layer. This is the first study to examine how hyperparameters influence learning machining stability diagrams. Learnings from a linear stability dataset are transferrable to nonlinear datasets, demonstrating the prediction model is physics-agnostic. Predictions accuracies of up to 97.2% were obtained. Since the data used to train the model includes all the vagaries and uncertainties of the cutting process, the results can inform self-optimizing and autonomous machining systems. </span></p></div></div></div> 2023-02-01T00:00:00+00:00 https://i-scholar.in/index.php/MTT/article/view/223389 Sound Intensity Analysis of Straight Bevel Gears Finished by Using AFF Process 2023-09-04T14:30:26+00:00 Vivek Rana mtphd1806103001@iiti.ac.in Anand Petare acpetare@iiti.ac.in Neelesh Kumar Jain nkjain@iiti.ac.in <div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>This article reports using the Abrasive flow finishing (AFF) process to finish straight bevel gears (SBG) to improve their microgeometry errors and surface characteristics. Microgeometry errors, surface roughness parameters, and dual flank roll testing parameters was compared for unfinished and the AFF finished SBG. An indigenously developed bevel gear test rig was used for the sound intensity measurement and experiments were conducted by varying speeds at four levels. Finishing of SBG by the AFF process reduced their microgeometry errors, surface roughness, and improved functional performance parameters, resulting in reduced sound power generation. This study proves the potential of the AFF process to improve gear quality and help to establish it as a cost-effective, productive, and sustainable non-traditional solution for high-quality gear finishing. </span></p></div></div></div> 2023-02-01T00:00:00+00:00 https://i-scholar.in/index.php/MTT/article/view/223391 Development of CNC Machine Code and User Interface for a 3-Axis Pneumatically Configurable Polishing Machine 2023-09-04T14:30:26+00:00 Onkar Chawla chawla.onkar@gmail.com Tarun Verma tarunverma9971@gmail.com Sunil Jha suniljha@mech.iitd.ac.in <div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>The polishing of freeform surfaces finds applications in a variety of niche areas where the surface characteristics have a defining impact on functional capabilities of the product. Pneumatically Configurable Polishing (PCP) is a recent addition to the available technologies which can generate surface finish of nanometric scales on freeform surfaces. The manipulative ease and determinism in polishing force control offered by the PCP process allow it to finish complex surface profiles in a highly repeatable way. The automation code for a CNC PCP machine-tool is developed to ensure the accuracy in the finished parts being produced. The machine code for CNC interpolation and the parametric process control have been carried out in the Parker Automation Manager software. The user interface has been designed and deployed using the JMobile HMI software. The PAM Visualization allows the user defined part program to be loaded in the controller from an external removable disk. The exchange of tags and process variables between the controller and HMI has been done using the OPC UA platform. A part program created using a CAM software is employed to finish a sample workpiece. The developed CNC machine code is successfully tested and evaluated for its functional performance and process repeatability. </span></p></div></div></div> 2023-02-01T00:00:00+00:00 https://i-scholar.in/index.php/MTT/article/view/223392 Effect of Applied Pneumatic Pressure on the Polishing Spot Size and the Total Normal Force in Pneumatically Configurable Polishing 2023-09-04T14:30:26+00:00 Tarun Verma tarunverma9971@gmail.com Onkar Chawla chawla.onkar@gmail.com Sunil Jha suniljha@mech.iitd.ac.in <div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>The present study pertains to a compliant polishing technique called Pneumatically Configurable Polishing (PCP) which uses the precise inflation of a thin elastomeric diaphragm or membrane using pneumatic pressure for generating nano level surface finish on substrate surfaces. The PC polishing tool which has a cup shape is made to contact the workpiece surface such that its flexible nature can adapt itself to the macro features on the workpiece. This inflated tool-work contact leads to the entrapment of the hard abrasives preplaced in the interface zone in the form of a slurry. The rotary motion of the tool along with the relative motion between the workpiece and tool, help to generate an improved surface finish in the interface area. The area of the finishing zone is an important outcome of the polishing regime because it defines the dimensions of the area which will be affected by the tool. It also helps to estimate the time needed for polishing a large area. Also, the force transmitted to the workpiece surface is an important measure to estimate the functional life of the tool. In the current study, the variation of the spot size and total normal force are modelled mathematically in terms of the physical and geometrical properties of the tool as well as the applied fluid pressure. The Hertz theory of contact is used to model the contact conditions in the polishing interface zone. The model studies the effect of pneumatic pressure on membrane inflation and its influence on the area of the polishing spot at varying working gaps. The effect of the applied fluid pressure is studied on the normal force experienced by the workpiece, and the results obtained from the model are validated with experimental verification under identical polishing conditions. The values obtained experimentally show a close agreement with the theoretical results obtained from the model. </span></p></div></div></div> 2023-02-01T00:00:00+00:00 https://i-scholar.in/index.php/MTT/article/view/223393 Design and Development of High-Speed Rotating Impeller for Turbo- Molecular Pump Through Topology Optimisation 2023-09-04T14:30:26+00:00 Prabhat Ranjan pranjan@barc.gov.in Ashok K. Wankhede ashokkw@barc.gov.in <div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>Additive Manufacturing (AM) process has potential to manufacture complex structures to cater the design requirement and process requirement for any specific application. However, this process is expensive as compared to the traditional and on-going advanced manufacturing process. The cost of AM process depends on volume/mass and size of the parts, and due to this, the AM manufactured part needs to be topologically optimised before manufacturing. In view of this, the manufacturer has to ensure the functionality and acceptability of design parameters about the computer aided design (CAD) model through a reliable numerical modelling technique for the topology optimisation (TO). Moreover, the CAD model also needs to be compatible for ease of manufacturing by AM process which is possible by post analysis and CAD modification. In the present paper, TO was implemented for a high-speed rotating impeller of a turbo-molecular pump (TMP) followed by manufacturing to achieve better performance. </span></p></div></div></div> 2023-02-01T00:00:00+00:00 https://i-scholar.in/index.php/MTT/article/view/223394 Approach for Determining the Availability of Machine Tools Based on Skill Level of Operator and Service Personnel 2023-09-04T14:30:26+00:00 Shashi Bhushan Gunjan gunjanshashi@gmail.com D. S. Srinivasu devadula@iitm.ac.in N. Ramesh Babu nrbabu@iitm.ac.in <div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>Machine tools (MTs) availability is a critical measure for production scheduling. On the other hand, the machine tool availability depends on its reliability (mean time between failure, MTBF) and maintainability (mean time to repair, MTTR), which depends on multiple factors and uncertainties. One can consider the skill level of operators and service personnel that influence MTBF and MTTR of machine tools, which in turn can affect operating cost. The studies on the effect of the skill level of operators and service personnel on MT availability are limited. Generally, MT availability should be higher to maintain reasonable operating costs. In the current work, a multi-objective optimization (MOO) problem was formulated to maximize the MT availability and minimize the MT life cycle cost, considering the skill levels of the MT operators and service personnel. The results of this study help the management identify the skill level of operators and service engineers for maximum MT availability. </span></p></div></div></div> 2023-02-01T00:00:00+00:00