scholarly journals Predicted Torque Model in Low-Frequency-Assisted Boring (LFAB) Operations

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1009
Author(s):  
Fernando Veiga ◽  
Alain Gil Del Val ◽  
Mari Luz Penalva ◽  
Octavio Pereira ◽  
Alfredo Suárez ◽  
...  

A low-frequency-assisted boring operation is a key cutting process in the aircraft manufacturing sector when drilling deep holes to avoid chip clogging based on chip breakage and, consequently, to reduce the temperature level in the cutting process. This paper proposes a predicted force model based on a commercial control-supported chip breaking function without external vibration devices in the boring operations. The model was fitted by conventional boring measurements and was validated by vibration boring experiments with different ranges of amplitude and frequency. The average prediction error is around 10%. The use of a commercial function makes the model more attractive for the industry because there is no need for intrusive vibration sensors. The low-frequency-assisted boring (LFAB) operations foster the chip breakage. Finally, the model is generic and can be used for different cutting materials and conditions. Roughness is improved by 33% when vibration conditions are optimal, considered as a vibration amplitude of half the feed per tooth. This paper presents, as a novelty, the analysis of low-frequency vibration parameters in boring processes and their effect on chip formation and internal hole roughness. This has a practical significance for the definition of a methodology based on the torque model for the selection of conditions on other hole-making processes, cutting parameters and/or materials.

2010 ◽  
Vol 455 ◽  
pp. 548-552
Author(s):  
J.S. Zhou ◽  
Bang Yan Ye ◽  
Xing Yu Lai

This research aims to improve the method of Mini-pore Drilling superimposed an axis vibration for hard-to-cut material of Austenitic Stainless Steel 1Cr18Ni9Ti, as well as to make it easier for the chips to be discharged. A mathematical model of vibration drilling is presented, and the relationship between the vibration parameters and cutting parameters to generate little and short broken-chips in vibration drilling is investigated, analyzed and verified by experiments. The results show that when the processing parameters meet the conditions given in this article, stable and reliable chip-breaking can be achieved. The results provide a theoretical guidance to achieve chip-breaking in mini-pore vibration drilling for hard-to-cut material.


Author(s):  
Takashi Matsumura ◽  
Yuji Musha

Abstract The paper discusses micro dimple millings with inclined ball end mills. Cutting process models are presented to control the dimple shapes and predict the cutting forces. In micro dimple milling, the cutter rotation axis is inclined to have the non-cutting time, during which the cutting edges don’t remove the material in a rotation of cutter. The end mill is fed at a high rate so that the machining areas removed by the cutting edges are not overlapped each other. The shapes and the alignment of the dimples are simulated for the cutting parameters in the mechanistic model. Then, the cutting forces are predicted for high machining accuracies. The cutting experiments were conducted to verify the micro dimple machining. The dimple shape model is validated in comparison between the simulated and the actual dimple shapes. The cutting forces are simulated to compare the measured ones. The force model works well to predict the cutting forces with the chip flow direction during a rotation of the cutter.


2017 ◽  
Vol 261 ◽  
pp. 77-84 ◽  
Author(s):  
Evlampia Stergianni ◽  
Dimitrios Sagris ◽  
Christos Tsiafis ◽  
Constantine David ◽  
Ioannis Tsiafis

In metal machining processes, it is necessary to study the vibration phenomena which take place in cutting area between the cutting tool and the workpiece in order to ascertain the factors that affect them. Subject of this paper is the analysis of the influence of vibration phenomena during micro-milling on chip formation mechanisms and thereby on the workpiece topomorphy. In particular, the cutting parameters, such as the cutting speed, the feed rate and the axial cutting depth, which affect the workpiece topomorphy are experimentally studied. Based on cutting force measurements correlated with the workpiece topomorphy under various cutting process parameters useful results are extracted. In this way, the impact of vibration phenomena, taking place in micro-milling due to the cutting process, on the workpiece topomorphy can be evaluated.


Author(s):  
Kang-Yul Bae ◽  
Young-Soo Yang ◽  
Myung-Su Yi ◽  
Chang-Woo Park

To manufacture a steel structure, in the first step, raw steel plate needs to be cut into proper sizes. Oxy-fuel flame is widely used in the cutting process due to its flexibility with respect to accessibility, plate thickness, cost, and material handling. However, the deformation caused by the cutting process frequently becomes a severe problem for the next process in the production of steel product. To decrease the deformation, the thermo-elasto-plastic behavior of the steel plate in the cutting process should be analyzed in advance. In this study, heat sources in oxy-ethylene flame cutting of steel plate were modeled first, and the heat flow in the steel plate was then analyzed by the models of the heat sources using a numerical simulation based on the finite element method. To verify the analysis by the numerical simulation including the models, a series of experiments were performed, and the temperature histories at several points on the steel plate during the cutting process were measured. Moreover, the predicted sizes of the heat-affected zone by the numerical simulations according to the variation in the cutting parameters were compared to the experimental results. The power functions of the relationship between the sizes of the heat-affected zone and cutting parameters were obtained by the recursion analysis using the correlation between the results and parameters. The results of the numerical simulation showed good agreement with those of the experiments, indicating that the proposed models of the heat sources and thermal analysis were feasible to analyze the heat flow in the steel plate during the cutting process.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Qiang Fang ◽  
Ze-Min Pan ◽  
Bing Han ◽  
Shao-Hua Fei ◽  
Guan-Hua Xu ◽  
...  

Drilling carbon fiber reinforced plastics and titanium (CFRP/Ti) stacks is one of the most important activities in aircraft assembly. It is favorable to use different drilling parameters for each layer due to their dissimilar machining properties. However, large aircraft parts with changing profiles lead to variation of thickness along the profiles, which makes it challenging to adapt the cutting parameters for different materials being drilled. This paper proposes a force sensorless method based on cutting force observer for monitoring the thrust force and identifying the drilling material during the drilling process. The cutting force observer, which is the combination of an adaptive disturbance observer and friction force model, is used to estimate the thrust force. An in-process algorithm is developed to monitor the variation of the thrust force for detecting the stack interface between the CFRP and titanium materials. Robotic orbital drilling experiments have been conducted on CFRP/Ti stacks. The estimate error of the cutting force observer was less than 13%, and the stack interface was detected in 0.25 s (or 0.05 mm) before or after the tool transited it. The results show that the proposed method can successfully detect the CFRP/Ti stack interface for the cutting parameters adaptation.


Author(s):  
Xiaohong Lu ◽  
Haixing Zhang ◽  
Zhenyuan Jia ◽  
Yixuan Feng ◽  
Steven Y. Liang

Micro-milling tool breakage has become a bottleneck for the development of micro-milling technology. A new method to predict micro-milling tool breakage based on theoretical model is presented in this paper. Based on the previously built micro-milling force model, the bending stress of the micro-milling cutter caused by the distributed load along the spiral cutting edge is calculated; Then, the ultimate stress of carbide micro-milling tool is obtained by experiments; Finally, the bending stress at the dangerous part of the micro-milling tool is compared with the ultimate stress. Tool breakage curves are drawn with feed per tooth and axial cutting depth as horizontal and vertical axes respectively. The area above the curve is the tool breakage zone, and the area below the curve is the safety zone. The research provides a new method for the prediction of micro-milling tool breakage, and therefore guides the cutting parameters selection in micro-milling.


Author(s):  
H.M. Magid

Purpose: In this study, plasma arc cutting (PAC) is an industrial process widely used for cutting various away types of metals in several operating conditions. Design/methodology/approach: It is carried out a systematic or an authoritative inquiry to discover and examine the fact, the plasma cutting process is to establish the accuracy and the quality of the cut in this current paper assessed a good away to better the cutting process. Findings: It found that the effect of parameters on the cutting quality than on the results performed to accomplish by statistical analysis. Research limitations/implications: The objective of the present work paper is to achieve cutting parameters, thus the quality of the cutting process depends upon the plasma gas pressure, scanning speed, cutting power, and cutting height. Practical implications: The product of the plasma cutting process experimentally has been the quality of the cutting equipment that was installed to monitor kerf width quality by exam the edge roughness, kerf width, and the size of the heat-affected zone (HAZ). Originality/value: The results reveal that were technically possessed of including all the relevant characteristics, then a quality control for the cutting and describe the consequence of the process parameters.


1999 ◽  
Author(s):  
J. R. Pratt ◽  
M. A. Davies ◽  
M. D. Kennedy ◽  
T. Kalmár-Nagy

Abstract A single-degree-of-freedom active cutting fixture is employed to reveal and analyse the hysteretic nature of the lobed stability boundary in a simple machining experiment. Specifically, the seventh stability lobe of a regenerative cutting process is mapped using experimental, analytical, and computational techniques. Then, taking width of cut as a control parameter, the transition from stable cutting to chatter is observed experimentally. The cutting stability is found to possess a substantial hysteresis so that either stable or chattering tool motions can exist at the same nominal cutting parameters, depending on initial conditions. This behavior is predicted by applying nonlinear regenerative chatter theory to an empirical characterization of the cutting force dependence on chip thickness. Time-domain simulations that incorporate both the nonlinear cutting force dependence on chip thickness and the multiple-regenerative effect due to the tool leaving the cut are shown to agree both qualitatively and quantitatively with experiment.


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