Cutting State Estimation via Chatter Mark on End Milled Surface and Analysis of Its Formation Mechanism Using Voxel Model Simulation

Author(s):  
Nobutoshi Ozaki ◽  
Shota Matsui ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama

Abstract When chatter vibrations occur during cutting, a characteristic pattern called chatter mark appears on the machined surface. In our previous studies, it was estimated that this chatter mark is formed by the tool (or workpiece) vibration in the normal direction with respect to the machined surface. We thus proposed a method to inversely analyze the chatter vibration information during cutting through the chatter mark using two-dimensional discrete Fourier transform. Previous studies confirmed that the analysis results of this method are in good agreement with those of the information obtained via conventional sensing. However, the correctness of the pattern formation mechanism is yet to be directly verified, as it is difficult to measure the cutting phenomenon directly. In this study, the chatter vibration during cutting was measured by the displacement of the tool-shank. Then, based on the results obtained in the static stiffness test, the movement of the tool edge was estimated. A cutting simulation using a voxel model was executed based on this tool-edge movement. When the simulation using the chatter vibration in the normal direction was performed, a chatter mark appeared on the simulated surface. It could thus be confirmed more directly that the analytical model is correct compared with the previous methods.

2020 ◽  
Vol 4 (1) ◽  
pp. 11 ◽  
Author(s):  
Angkush Kumar Ghosh ◽  
AMM Sharif Ullah ◽  
Akihiko Kubo ◽  
Takeshi Akamatsu ◽  
Doriana Marilena D’Addona

Industry 4.0 requires phenomenon twins to functionalize the relevant systems (e.g., cyber-physical systems). A phenomenon twin means a computable virtual abstraction of a real phenomenon. In order to systematize the construction process of a phenomenon twin, this study proposes a system defined as the phenomenon twin construction system. It consists of three components, namely the input, processing, and output components. Among these components, the processing component is the most critical one that digitally models, simulates, and validates a given phenomenon extracting information from the input component. What kind of modeling, simulation, and validation approaches should be used while constructing the processing component for a given phenomenon is a research question. This study answers this question using the case of surface roughness—a complex phenomenon associated with all material removal processes. Accordingly, this study shows that for modeling the surface roughness of a machined surface, the approach called semantic modeling is more effective than the conventional approach called the Markov chain. It is also found that to validate whether or not a simulated surface roughness resembles the expected roughness, the outcomes of the possibility distribution-based computing and DNA-based computing are more effective than the outcomes of a conventional computing wherein the arithmetic mean height of surface roughness is calculated. Thus, apart from the conventional computing approaches, the leading edge computational intelligence-based approaches can digitize manufacturing processes more effectively.


Author(s):  
Shinnosuke Yamashita ◽  
Tatsuya Furuki ◽  
Hiroyuki Kousaka ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
...  

Abstract Recently, the demand of carbon fiber reinforced plastics (CFRP) has been rapidly increased in various fields. In most cases, CFRP products requires a finish machining like cutting or grinding. In the case of an end-milling, burrs and uncut fibers are easy to occur. On the other hand, a precise machined surface and edge will be able to obtain by using the grinding tool. Therefore, this research has been developed a novel the cBN electroplated end-mill that combined end-mill and grinding tool. In this report, the effectiveness of developed tool was investigated. First, the developed tool cut the CFRP with side milling. As the result, the cBN abrasives that were fixed on the outer surface of developed tool did not drop out. Next, the end-milled surface of CFRP was ground with the developed tool under several grinding conditions based on the Design of Experiment. Consequently, the optimum grinding condition that can obtain the sharp edge which does not have burrs and uncut fibers was found. However, surface roughness was not good enough. Thus, an oscillating grinding was applied. In addition, the theoretical surface roughness formula in case using the developed tool was formularized. As the result, the required surface roughness in the airplane field was obtained.


Author(s):  
Lang Ruan ◽  
Jin Chen ◽  
Qiuju Guo ◽  
Xiaobo Zhang ◽  
Yuli Zhang ◽  
...  

In scenarios such as natural disasters and military strike, it is common for unmanned aerial vehicles (UAVs) to form groups to execute reconnaissance and surveillance. To ensure the effectiveness of UAV communications, repeated resource acquisition issues and transmission mechanism design need to be addressed urgently. In this paper, we build an information interaction scenario in a Flying Ad-hoc network (FANET). The data transmission problem with the goal of throughput maximization is modeled as a coalition game framework. Then, a novel mechanism of coalition selection and data transmission based on group-buying is investigated. Since large-scale UAVs will generate high transmission overhead due to the overlapping resource requirements, we propose a resource allocation optimization method based on distributed data content. Comparing existing works, a data transmission and coalition formation mechanism is designed. Then the system model is classified into graph game and coalition formation game. Through the design of the utility function, we prove that both games have stable solutions. We also prove the convergence of the proposed approach with coalition order and Pareto order. Binary log-linear learning based coalition selection algorithm (BLL-CSA) is proposed to explore the stable coalition partition of system model. Simulation results show that the proposed data transmission and coalition formation mechanism can achieve higher data throughput than the other contrast algorithms.


2015 ◽  
Vol 3 (2) ◽  
Author(s):  
Syed Adnan Ahmed ◽  
Jeong Hoon Ko ◽  
Sathyan Subbiah ◽  
Swee Hock Yeo

This paper describes a new method of microtexture generation in precision machining through self-excited vibrations of a diamond cutting tool. Conventionally, a cutting tool vibration or chatter is detrimental to the quality of the machined surface. In this study, an attempt is made to use the cutting tool's self-excited vibration during a cutting beneficially to generate microtextures. This approach is named as “controlled chatter machining (CCM).” Modal analysis is first performed to study the dynamic behavior of the cutting tool. Turning processes are then conducted by varying the tool holder length as a means to control vibration. The experimental results indicate that the self-excited diamond cutting tool can generate microtextures of various shapes, which depend on the cutting tool shank, cutting speed, feed, and cutting depth. The potential application of this proposed technique is to create microtextures in microchannels and microcavities to be used in mass and heat transfer applications.


2014 ◽  
Vol 1077 ◽  
pp. 61-65
Author(s):  
Pei Yan ◽  
Xiang Su ◽  
Gang Wang ◽  
Yi Ming Rong

As the development of new materials and high speed machining, cutting fluid becomes more and more important because of its functions of cooling, lubrication, corrosion protection and cleaning. The main purposes of cutting fluid are decreasing temperature, reducing friction, extending tool life and improving machining efficiency. In precision machining, high machined surface integrity is the most important. In this paper, a preliminary experimental study on effect of two different cutting fluids on milled surface quality of iron-base superalloy was taken. The surface morphology, roughness, micro hardness and residual stress of the machined surface were investigated. The results showed that the material properties and geometric characteristics of the machined surface were significantly affected by cutting fluid conditions. The effect of cutting fluid on machined surface quality and service performance will become an important research direction. This paper also suggests the main contents of the further research on effect of cutting fluids on machined surface.


2012 ◽  
Vol 445 ◽  
pp. 1041-1046
Author(s):  
Hamed Razavi ◽  
Mohammad Javad Nategh ◽  
H. Soleimanimehr

The experimental investigation of UAT shows that the movement of cutting tool edge relative to the workpiece results from the cutting speed, feed speed and tools vibration in tangential direction affects the lateral machined surface of workpiece and leaves a repeating pattern of toothed regions on it. In UAT process, because of constant feed rate of tool toward workpiece, the cutting tool never separates from workpiece, though the tool rake face may separate periodically from chip in every cycle of vibration. This results in an increase in the surface hardness of the lateral machined surface in comparison with conventional turning (CT). The results of the present study confirm the advantage of UAT as far as the lower cutting force is concerned compared with CT. The higher surface hardness of the lateral surface observed in UAT causes the maximum cutting force to increase but the average force decreases with respect to CT.


2010 ◽  
Vol 4 (3) ◽  
pp. 243-251 ◽  
Author(s):  
Hiroyasu Iwabe ◽  
◽  
Hideaki Matsuhashi ◽  
Hayato Akutsu ◽  
Tomoyuki Shioya ◽  
...  

In this paper, the FEM analysis and the machining of a workpiece using a non-rotational tool are attempted in order to produce a highly accurate surface on a thin wall. Also, the machining accuracy of the thin wall produced by the non-rotational tool is compared with that produced by an end mill. The main results are as follows. (1) FEM models for the tool and workpiece are made and the machining accuracy is predicted based on the deflection analysis using FEM due to the cutting force. (2) The tendency of the shape of machined surface is almost coincident with that of the predicted shape, so the propriety of the method of analysis is verified. (3) Both dimensional and shape error on the inside and outside surfaces of the workpiece produced by the non-rotational tool prove larger than the predicted values. Although the shape error proved a little larger than the predicted value, the target value of 5μm was achieved. (4) It is shown that the dimensional error due to under cutting decreases with the decrease in the radius of the tool edge. And also, on and after the second cutting process, the cutting at the commanded depth of cut was achieved even if the micro depth of cut.


2010 ◽  
Vol 42 ◽  
pp. 363-366 ◽  
Author(s):  
Dao Hui Xiang ◽  
Xin Tao Zhi ◽  
Guang Xi Yue ◽  
Guo Fu Gao ◽  
Bo Zhao

Al/SiCp composites with excellent physical and mechanical properties are applied widely in the aerospace, automotive, national defense, electronics and other fields. High content and high hardness SiC particles lead to poor machinability and that further application is restricted. Surface microstructure and surface formation mechanism of Al/SiCp composites were studied under condition of ultrasonic vibration milling and conventional milling. The experimental results show that machined surface had the same defects, but SiC particles were mainly direct sheared in ultrasonic milling different from the conventional milling, the roughness (Ra) of the surface generated in the ultrasonic vibration milling was smaller. At last, the formation mechanism of surface topography in the ultrasonic milling was analyzed. The research indicated that ultrasonic milling could obtain better surface quality than conventional milling and with high efficient.


2009 ◽  
Vol 69-70 ◽  
pp. 306-310
Author(s):  
Fu Gang Yan ◽  
Cai Xu Yue ◽  
Xian Li Liu ◽  
Yu Fu Li ◽  
Shu Yi Ji

Tool wear plays an important role in cutting process research. It affects the quality of machined surface and cutting parameter to a great extent, such as cutting force, cutting temperature and cutting quiver. In order to predict tool wear in hard cutting process by using FEM method, the character of tool wear during cutting process is presented firstly, and Usui’s tool wear rate model is introduced. Then the FEM model for steady state cutting process using Abaqus is established. FEM model describes the workpiece material characteristic accurately for the process of PCBN tool cutting GCr15 by adoptiving Johnson-Cook constitutive model. Simulation results of steady cutting process offer foundation to simulate tool wear.


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