scholarly journals Pendekatan alternatif dalam menghasilkan stability lobes diagram untuk memprediksi getaran chatter pada proses pemesinan berdinding tipis

2021 ◽  
Vol 5 (1) ◽  
pp. 48-57
Author(s):  
Agus Susanto
Keyword(s):  
Machining Process ◽  
Experimental Result ◽  
Process Chain ◽  
Chatter Vibration ◽  
Stability Lobe Diagram ◽  
Stability Lobe ◽  
Multi Stage ◽  
Alternative Approach ◽  
Finishing Process ◽  
Manufacturing Process Chain

Machining is widely used for finishing process of the entire manufacturing process chain. Machining process of thin plate, however, is not an easy task. This is because excessive vibration (chatter) can rise during operation. To predict the chatter vibration, a stability lobe diagram (SLD) is usually utilized which is strongly dependent on the frequency response function (FRF). This paper proposes an alternative approach for analyzing modal analysis by finite element method (FEM) to obtain FRF during machining thin-walled plate. The result showed that simulation result has good enough agreement to experimental result with slight differences caused by the assumed boundary conditions in the FEM process. This approach can be used to reduce the use of hammering tests and can be used to get FRF of multi stage working.

Stability Prediction of Milling Process With Closed Machining System Dynamics With Flexible Thin-Walled Workpiece

2015 ◽  
Author(s):  
Chao Xu ◽  
Pingfa Feng ◽  
Dingwen Yu ◽  
Zhijun Wu ◽  
Jianfu Zhang
Keyword(s):  
Support System ◽  
Milling Process ◽  
Machining Process ◽  
Stability Lobe Diagram ◽  
Closed Model ◽  
Flexible Support ◽  
Stability Lobe ◽  
Machining System ◽  
Thin Walled ◽  
The Stability

Despite recent advances and improvements in modeling and prediction of the dynamics of the machining process, an efficient machining process is limited due to chatter and instability of machining system. In fact, the machining system contains various kinds of joints, which cause difficulties in dynamics modeling, simulation and prediction. Moreover, the flexible support system results in large deformation and violent vibration of the workpiece when machining, and the thin-walled workpiece easily gives rise to the chatter of the machining system. Therefore, the dynamics of the flexible support system was considered to calculate stability lobe diagram in the modeling of milling process. The whole machining system was regarded as a closed loop composed by the machine tool structures, support, workpiece and machining process. In this paper, the receptance coupling (RC) method was introduced to predict the dynamics of the closed machining system. A milling process was taken for example to predict the chatter limitations using the dynamics of closed model. The mathematical model of the machining system (machine tool structures, spindle, holder and tool), together with the details of joint contacts, was given based on the RC method. The RC model was used to obtain the dynamics of the system, while receptance of the tool point was coupled. Based on the coupling model of the machining system, the depth limitations under different speeds were estimated for the technology parameter optimization in milling process. The response was considered to be the sum of the cutting point and the support system. The flexibility of the support system was considered to be the feedback of the cutting stiffness. By this means, the traditional model was modified to calculate the stability lobe diagram based on the dynamics of the spindle and support system. Furthermore, the milling experiment was carried out to verify the prediction results, and the dominant natural frequencies of receptance at tool point were obtained by modal testing to define the stability lobe diagram. It was found that the chatter results matched well with the stability lobes. It was concluded that the support system with poor stiffness might cause violent chatter especially when the workpiece was thin-walled. The cutting depth limitations of the flexible support system were lower than that of the rigid one. Moreover, this closed model of the machining system is appropriate for the chatter prediction of the flexible support system or thin-walled workpiece, so it is helpful for a better parameter optimization.

Chatter reduction in slender boring bar via a tunable holder with variable mass and stiffness

2017 ◽  
Vol 232 (12) ◽  
pp. 2098-2108 ◽  
Author(s):  
Sajad Hayati ◽  
Mohammad Hajaliakbari ◽  
Yalda Rajabi ◽  
Sajad Rasaee
Keyword(s):  
Time Domain ◽  
Variable Mass ◽  
Stable Condition ◽  
Domain Model ◽  
Machining Process ◽  
Machining Processes ◽  
Stability Lobe Diagram ◽  
Chatter Suppression ◽  
Stability Lobe ◽  
The Time Domain

In this study, a new strategy is presented to increase the machining stability due to chatter suppression for boring and turning machining processes. The proposed approach is based on varying the position of stability lobes via changing mechanical properties of the tool body such as the mass and stiffness. Because of the shape of stability lobe diagrams, having a tool with a tunable stability lobe diagram can be useful to alter an unstable condition to a stable condition. For this purpose, a structure for the tool body is designed that is consisted of a hollow body with a core as a tunable screw inside it. As the core gets in or out, it changes the mass and stiffness of the tool body that leads to change the position of stability lobe diagram. In order to study the effect of designed structure on stability, the structure is simulated using a validated finite element time domain model. The time domain simulation shows a considerable improvement in stability of process. The strategy is experimentally applied to the process via modulation of the tool structure in the machining process to validate the simulation results. The experimental results have a high coincidence with theory and show a good improvement in stability.

scholarly journals Multi-Stage Cold Forging Process for Manufacturing a High-Strength One-Body Input Shaft

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 532
Author(s):  
A Jo ◽  
Myeong Jeong ◽  
Sang Lee ◽  
Young Moon ◽  
Sun Hwang
Keyword(s):  
High Strength ◽  
Microstructural Characterization ◽  
Fatigue Tests ◽  
Machining Process ◽  
Cold Forging ◽  
Element Analysis ◽  
Forging Process ◽  
Input Shaft ◽  
Multi Stage ◽  
The One

A multi-stage cold forging process was developed and complemented with finite element analysis (FEA) to manufacture a high-strength one-body input shaft with a long length body and no separate parts. FEA showed that the one-body input shaft was manufactured without any defects or fractures. Experiments, such as tensile, hardness, torsion, and fatigue tests, and microstructural characterization, were performed to compare the properties of the input shaft produced by the proposed method with those produced using the machining process. The ultimate tensile strength showed a 50% increase and the torque showed a 100 Nm increase, confirming that the input shaft manufactured using the proposed process is superior to that processed using the machining process. Thus, this study provides a proof-of-concept for the design and development of a multi-stage cold forging process to manufacture a one-body input shaft with improved mechanical properties and material recovery rate.

Electrical Discharge Grinding (EDG) of Polycrystalline Diamond - Effect of Machining Polarity

2014 ◽  
Vol 1025-1026 ◽  
pp. 628-632 ◽  
Author(s):  
Mohammad Zulafif Rahim ◽  
Song Lin Ding ◽  
John Mo
Keyword(s):  
Electrical Discharge ◽  
Complex Geometry ◽  
Polycrystalline Diamond ◽  
Machining Process ◽  
Morphological Examination ◽  
Carbon Structure ◽  
Finishing Process ◽  
Advanced Machining ◽  
The Difference ◽  
Pcd Tools

Electrical discharge grinding (EDG) is an advanced machining process and can be utilised to fabricate complex geometry of PCD tools. However, the PCD removal mechanism in this process is complicated. This study was carried out to understand the difference in PCD surface structure with difference EDG polarities. The study revealed that the finishing process with negative polarity is the reason for the porous structure on the surface. Further analysis on the chemical element and carbon structure were implemented as the morphological examination of the surface.

A Goal-Oriented, Inverse Decision-Based Design Method to Achieve the Vertical and Horizontal Integration of Models in a Hot Rod Rolling Process Chain

2017 ◽  
Author(s):  
Anand Balu Nellippallil ◽  
Vignesh Rangaraj ◽  
B. P. Gautham ◽  
Amarendra Kumar Singh ◽  
Janet K. Allen ◽  
...  
Keyword(s):  
Manufacturing Process ◽  
Design Method ◽  
Manufacturing Processes ◽  
Process Chain ◽  
Structure Property ◽  
Horizontal Integration ◽  
Design Exploration ◽  
Unit Operations ◽  
Manufacturing Process Chain ◽  
Decision Based Design

Reducing the manufacturing and marketing time of products by means of integrated simulation-based design and development of the material, product, and the associated manufacturing processes is the need of the hour for industry. This requires the design of materials to targeted performance goals through bottom-up and top-down modeling and simulation practices that enables handshakes between modelers and designers along the entire product realization process. Manufacturing a product involves a host of unit operations and the final properties of the manufactured product depends on the processing steps carried out at each of these unit operations. In order to effectively couple the material processing-structure-property-performance spaces, there needs to be an interplay of the systems-based design of materials with enhancement of models of various unit operations through multiscale modeling methodologies and integration of these models at different length scales (vertical integration). This ensures the flow of information from one unit operation to another thereby establishing the integration of manufacturing processes (horizontal integration). Together these types of integration will support the decision-based design of the manufacturing process chain so as to realize the end product. In this paper, we present a goal-oriented, inverse decision-based design method to achieve the vertical and horizontal integration of models for the hot rolling and cooling stages of the steel manufacturing process chain for the production of a rod with defined properties. The primary mathematical construct used for the method presented is the compromise Decision Support Problem (cDSP) supported by the proposed Concept Exploration Framework (CEF) to generate satisficing solutions under uncertainty. The efficacy of the method is illustrated by exploring the design space for the microstructure after cooling that satisfies the requirements identified by the end mechanical properties of the product. The design decisions made are then communicated in an inverse manner to carry out the design exploration of the cooling stage to identify the design set points for cooling that satisfies the new target microstructure requirements identified. Specific requirements such as managing the banded microstructure to minimize distortion in forged gear blanks are considered in the problem. The proposed method is generic and we plan to extend the work by carrying out the integrated decision-based design exploration of rolling and reheating stages that precede to realize the end product.

Discrete Time-Delay Optimal Control Method for Experimental Active Chatter Suppression and Its Closed-Loop Stability Analysis

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Xingwu Zhang ◽  
Ziyu Yin ◽  
Jiawei Gao ◽  
Jinxin Liu ◽  
Robert X. Gao ◽  
...  
Keyword(s):  
Optimal Control ◽  
Closed Loop ◽  
Control Method ◽  
Trial And Error ◽  
Stability Lobe Diagram ◽  
Weighting Matrix ◽  
Chatter Suppression ◽  
Stability Lobe ◽  
Optimal Control Method ◽  
Discrete Time Delay

Chatter is a self-excited and unstable vibration phenomenon during machining operations, which affects the workpiece surface quality and the production efficiency. Active chatter control has been intensively studied to mitigate chatter and expand the boundary of machining stability. This paper presents a discrete time-delay optimal control method for chatter suppression. A dynamical model incorporating the time-periodic and time-delayed characteristic of active chatter suppression during the milling process is first formulated. Next, the milling system is represented as a discrete linear time-invariant (LTI) system with state-space description through averaging and discretization. An optimal control strategy is then formulated to stabilize unstable cutting states, where the balanced realization method is applied to determine the weighting matrix without trial and error. Finally, a closed-loop stability lobe diagram (CLSLD) is proposed to evaluate the performance of the designed controller based on the proposed method. The CLSLD can provide the stability lobe diagram with control and evaluate the performance and robustness of the controller cross the tested spindle speeds. Through many numerical simulations and experimental studies, it demonstrates that the proposed control method can make the unstable cutting parameters stable with control on, reduce the control force to 21% of traditional weighting matrix selection method by trial and error in simulation, and reduce the amplitude of chatter frequency up to 78.6% in experiment. Hence, the designed controller reduces the performance requirements of actuators during active chatter suppression.

Numerical Simulation of Cutting Force in High Speed Machining of Inconel 718

2020 ◽  
Vol 856 ◽  
pp. 43-49
Author(s):  
Santosh Kumar Tamang ◽  
Nabam Teyi ◽  
Rinchin Tashi Tsumkhapa
Keyword(s):  
Cutting Force ◽  
Inconel 718 ◽  
High Speed ◽  
Experimental Results ◽  
Machining Process ◽  
Experimental Result ◽  
Work Piece ◽  
High Speed Machining ◽  
Numerical Result ◽  
3D Software

Machining is one of the major manufacturing processes that converts a raw work piece of arbitrary size into a finished product of definite shape of predetermined size by suitably controlling the relative motion between the tool and the work. Lately, machining process is shifting towards high speed machining (HSM) from conventional machining to improve and efficiently increase production, and towards dry machining from excessive coolant used wet machining to improve economy of production. And the tools used are mostly hardened alloys to facilitate HSM. The work piece materials are continually improving their properties by emergence and development of newer and high resistive super alloys (HRSA). In this paper an attempt has been made to validate an experimental result of cutting force obtained by performing HSM on an HRSA Inconel 718, by comparing it with the numerical result obtained by simulating the same setting using DEFORM 3D software. Based on the comparison it is found that the simulated results exhibit close proximity with the experimental results validating the experimental results and the effectiveness of the software.

Modelling and simulation of surface topography machined by peripheral milling considering tool radial runout and axial drift

2019 ◽  
Vol 233 (12) ◽  
pp. 2227-2240 ◽  
Author(s):  
Hui-Qun Chen ◽  
Qing-Hui Wang
Keyword(s):  
Surface Roughness ◽  
Surface Topography ◽  
Surface Finish ◽  
Dominant Frequency ◽  
Peripheral Milling ◽  
Stability Lobe Diagram ◽  
Vector Operation ◽  
Good Surface ◽  
Stability Lobe ◽  
Feed Mark

Based on the Z-map model of a workpiece and the dynamic cutting forces model of peripheral milling in which the regenerative effect of tool radial runout and axial drift are considered, a model for the prediction of surface topography in peripheral milling operations is presented. According to the stability lobe diagram obtained by the zero-order analytical method, the relationship between spindle speed and surface topography, the tool radial runout, and the axial drift following the chatter are studied. The results show that a stable cutting status but a poor surface finish is obtained at the spindle speeds at which the dominant frequency of the milling system is integral multiples of the selected machining frequency, and a stable cutting status with a good surface finish can be obtained near and on the left side of the resonant spindle speeds determined by the predicted stability lobe diagram. The motion equations of any tooth end mill for peripheral milling are established, and these equations are based on the transformation matrix and the vector operation principle of motion-homogeneous coordinates. In addition, the simulation algorithm and the system of surface topography generated in peripheral milling are given based on the Z-map model. Cutting tests are carried out, and good agreement between the measured surface topographies and the topographies predicted by the model in this study is found in terms of their shape, magnitude, feed mark, profile height of cross-section, and surface roughness. The simulation results show that the milling surface roughness increases with the increase in feed per tooth, which further shows that this simulation system has high credibility. Thus, the simulation and experimental results can provide some practical instructions for the actual peripheral milling in determining the optimal machining conditions.

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