A Bending-Machining Hybrid Process for Angular Dimensional Accuracy Enhancement

Author(s):  
Ye Li ◽  
Anand Sekar

Bending is a fundamental manufacturing process to form sheet metals into intended angular geometries. Although the process has been extensively studied, predicting its accuracy is still challenging due to the Springback phenomenon inherent to the process. This research intends to combine bending and machining processes to improve bent workpiece angular dimensional accuracy. A minimum enclosing CAD model is first obtained by determining optimum thickness from the bend part CAD model to accommodate the estimated Springback in order to guide the selection of blank workpiece dimension for this bending/machining strategy. Then the machining areas are determined and the cutting forces are predicted to estimate the deformation in the machining process. Toolpath is planned on the surface profile considering both the cutter deflection and the incurred workpiece deformation during machining. This project aims to produce a bending part with the desired dimensional accuracy through a hybrid manufacturing approach. More importantly, it also provides a technological foundation to prototype angled parts at a low cost by avoiding high expenses in making new die.

2019 ◽  
Vol 895 ◽  
pp. 8-14 ◽  
Author(s):  
Y. Nagaraj ◽  
N. Jagannatha ◽  
N. Sathisha

Glass, being considered as hard and brittle material is very difficult to machine into desired shapes. The readily available conventional machining process does not provide good surface finish thus requires additional machining process. This paper reviews the different existing non conventional machining process accessible till today for the machining of glass materials. This paper also discusses the advantages and disadvantages of the existing non conventional machining processes. The various hybrid non conventional machining processes are also studied with focus on machining output characteristics like MRR, surface finish, tool wear rate. This paper summarizes the selection of hybrid non conventional machining processes for the various type of glass.


2022 ◽  
Vol 11 (2) ◽  
pp. 193-202
Author(s):  
G. Venkata Ajay Kumar ◽  
A. Ramaa ◽  
M. Shilpa

In most of the machining processes, the complexity arises in the selection of the right process parameters, which influence the machining process and output responses such as machinability and surface roughness. In such situations, it is important to estimate the inter-relationships among the output responses. One such method, Decision-Making Trial and Evaluation Laboratory (DEMATEL) is applied to study the inter-relationships of the output responses. Estimation of proper weights is also crucial where the output responses are conflicting in nature. In the current study, DEMATEL technique is used for estimating the inter-relationships for output responses in machining of EN 24 alloy under dry conditions. CRiteria Importance Through Inter-criteria Correlation (CRITIC) method is used to estimate the weights and finally the optimal selection of machining parameters is carried out using Techniques for Order Preference by Similarity to an Ideal Solution (TOPSIS) method. The model developed guides the decision maker in selection of precise weights, estimation of the inter relationships among the responses and selection of optimal process parameters.


2015 ◽  
Vol 766-767 ◽  
pp. 914-920
Author(s):  
V. Sivaraman ◽  
S. Prakash

In the modern competitive scenario in manufacturing industries, producing products with low cost, less time and good quality are the ultimate goal of any manufacturer. To achieve the goal, several optimization tools are developed to optimize the process parameters of the machining process. Turning is one of the machining processes that cannot be avoided in any manufacturing industries. In this review, optimization of process parameters in turning process by computational intelligence (CI) paradigms for the past ten years is studied. Optimization by CI paradigms such as Fuzzy System (FS), Evolutionary Computation techniques Genetic Algorithm (GA), Swarm Intelligence including Particle Swarm Optimization (PSO), Ant Colony Optimization (ACO), Artificial Neural Networks (ANN) etc., is considered. In turning process, surface roughness, tool wear, production time and cost are optimized.


Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5326
Author(s):  
Andrés Sio-Sever ◽  
Erardo Leal-Muñoz ◽  
Juan Manuel Lopez-Navarro ◽  
Ricardo Alzugaray-Franz ◽  
Antonio Vizan-Idoipe ◽  
...  

This work presents a non-invasive and low-cost alternative to traditional methods for measuring the performance of machining processes directly on existing machine tools. A prototype measuring system has been developed based on non-contact microphones, a custom designed signal conditioning board and signal processing techniques that take advantage of the underlying physics of the machining process. Experiments have been conducted to estimate the depth of cut during end-milling process by means of the measurement of the acoustic emission energy generated during operation. Moreover, the predicted values have been compared with well established methods based on cutting forces measured by dynamometers.


2013 ◽  
Vol 773-774 ◽  
pp. 348-354 ◽  
Author(s):  
Sriram Srinivasan ◽  
Lakshmikanthan Srivatsan ◽  
Rajaram Sathyanarayan ◽  
B. Vijaya Ramnath

The work of manufacturing engineers is to utilize the minimum amount of energy or resources in bringing out a product without compromising on quality. Hence, to achieve this, the engineers must figure out the optimum or the best possible method to fabricate a product. This paper uses a multi criteria decision making (MCDM) model namely Analytical Hierarchical Process (AHP) to determine the best possible machining process to achieve the optimum results for an engraving operation on gear face in an automobile industry which uses five nontraditional machining processes viz; Laser Beam Machining (LBM), Ultrasonic Machining (USM), Electric Discharge Machining (EDM), Electrochemical Machining (ECM) and Electron Beam Machining (EBM). The five criteria considered in this paper are Material Removal Rate (MRR), Surface Finish, Depth Damage, Tolerance and Toxicity. The AHP result shows that ECM is the most suitable machining process as compared to others.


1995 ◽  
Vol 117 (3) ◽  
pp. 331-339 ◽  
Author(s):  
R. Kovacevic ◽  
C. Cherukuthota ◽  
R. Mohan

During machining, due to relative motion between tool and workpiece, severe thermal/frictional conditions exist at the tool-chip interface. Metal machining processes can be more efficient in terms of increasing the metal removal rate and lengthening tool life, if the thermal/frictional conditions are controlled effectively. A high pressure waterjet assisted coolant/lubricant system that can be used in conjunction with rotary tools (e.g., face milling) is developed here. The performance of this system is evaluated in terms of cutting force, surface quality, tool wear, and chip shape. The improvement in the effectiveness of the developed system with increase in water pressure and orifice diameter is also investigated. Stochastic modeling of the surface profile is performed to obtain more information about the role of waterjet in the machining process.


2015 ◽  
Vol 47 (2) ◽  
pp. 229-235 ◽  
Author(s):  
D. Petkovic ◽  
M. Madic ◽  
G. Radenkovic

Selection of the most suitable non-conventional machining process (NCMP) for a ceramics machining represents a multi-criteria decision making (MCDM) problem. This paper describes the application of relatively novel MCDM methods for selecting the most suitable NCMP for the ceramics machining. By applying WASPAS and COPRAS methods, ten NCMPs (alternatives) were ranked based on the ten criteria. Comparison of obtained ranking performances with other MCDM methods used by previous researchers was carried out in order to demonstrate WASPAS and COPRAS applicability and capability for non-conventional machining process selection.


2011 ◽  
Vol 223 ◽  
pp. 267-276 ◽  
Author(s):  
Jae Bong Yang ◽  
Wei Tsu Wu ◽  
Shesh Srivatsa

Finite element modeling of the machining process has been quite successful in recent years. The model can be used to better understand the interactions between chip flow, heat generation, residual stress, tool stress, tool wear, tool chatter and dimensional accuracy. One of the key inputs to the model is the high strain rate (>104 1/sec) flow stress data. The split Hopkinson bar test has been commonly used to measure the flow stress at these high strain rates. The method is expensive and typically limited to the strain rate range from 102 to 104 1/sec. To overcome these limitations, an optimization based inverse methodology was developed. In this technique, the measured and predicted cutting forces were matched by iteratively adjusting the coefficients in the flow stress constitutive model. Since the method requires many FEM simulations to reach the final optimal condition, a computationally efficient FEM solver using ALE (Arbitrary Lagrangian Eulerian) method was adopted to make the method practical. The method was validated with experimental data with excellent agreement.


Author(s):  
Mustafizur Rahman ◽  
Keng Soon Woon ◽  
Wee Keong Neo

Abstract It is an unarguably fact is that the current trend in manufacturing is miniaturization of products with extreme surface finish. I addition, the surface finish and dimensional accuracy requirements of products as well components are getting remarkably stringent, especially in the areas of vision, information, biotech, environmental, measurement and medical industries. Moreover, these products need to accommodate increased number of functions. Production of such products and parts of micron level size with very high dimensional accuracy of nano meter level is getting more importance because of a steadily increasing demand for such industrial products. To satisfactorily meet these challenges micro/nanomachining technology must be developed. Such machining is usually performed either using techniques based on energy beams (beam-based micro-machining) or using solid cutting tools (tool-based micro/nanomachining). Some of the limitations of beam-based micro-machining are due to poor control of 3D structures, low aspect ratio of products and also low material removal rate. In addition, special facilities are required to perform these processes and the maximum achievable dimensions are relatively small. However, with the application of tool-based micro/nanomachining technology some of these limitations can be satisfactorily overcome using ultra precision machine tools and solid cutting tools to produce the micro-features with well-controlled shape, features and tolerances. In many cases, compound or hybrid or simultaneous machining process is required for effectively performing micromachining. To meet the challenges, multi-process machines are required and unfortunately such machines are not available. Consequently, the author will present the development of a first-of-its-kind multi-process machine tool and the innovative approaches to develop various compound, hybrid and simultaneous machining processes for the successful implementation of micromachining. Recently, nanomachining of difficult-to-machine materials is also getting more importance with the pervasive demand for fabrication of miniature, thinner and lighter products, intricate micro-shapes and structures on such materials. In addition, the products also require nano meter level surface finish. The author would like to present his contribution especially in the area ductile mode machining of brittle materials. This paper also presents the recent developments in the areas of deeper understanding of the mechanisms and machining technologies to generate nano-finish surface by machining processes. In this paper, the basic understanding of nanomachining mechanism, ‘extrusion-like’ chip formation metal cutting is briefly discussed. With the emergence of hybrid freeform surfaces to increase the optical performance and to provide new functions. To fulfill these objectives, the author and his team have carried out ultra-precision machining using fast tool servo (FTS) and slow slide servo (SSS) mechanisms. Some typical examples of the development of innovative nano machining processes and products have been presented in this paper. Finally, the development of a rotating tool for continuous production of radial Fresnel lenses has been presented.


2019 ◽  
Vol 29 (2) ◽  
pp. 249-271 ◽  
Author(s):  
Partha Das ◽  
Shankar Chakraborty

In order to achieve higher dimensional accuracy along with better surface quality, the conventional machining processes have now-a-days being replaced by non-traditional machining (NTM) processes, because of their ability to generate intricate shape geometries on various advanced engineering materials. In order to exploit their fullest machining potential, it is often recommended to operate those NTM processes at their optimal parametric settings. Several optimization tools and techniques are now available which can be effectively applied to obtain the optimal parametric conditions of those processes. In this paper, Taguchi method and super ranking concept are integrated together to present an efficient optimization technique for simultaneous optimization of three NTM processes, i.e. electro-discharge machining process, wire electro-discharge machining process and electro-chemical discharge drilling process. The derived results are validated with the help of developed regression equations, which show that the proposed approach outperforms the other popular multi-response optimization techniques. Analysis of variance is also performed to identify the most influencing control parameters for the considered NTM processes. The developed response surface plots further help the process engineers in identifying the effects of various NTM process parameters on the calculated sum of squared rank values.


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