• Title/Summary/Keyword: Tool Failure

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A Study on the Cutting Characteristics and Detection of the Abnormal Tool State in Hard Turning (고경도강 선삭시 절삭특성 및 공구 이상상태 검출에 관한 연구)

  • Lee S.J.;Shin H.G.;Kim M.H.;Kim J.T.;Lee H.K.;Kim T.Y.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.452-455
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    • 2005
  • The cutting characteristics of hardened steel by a PCBN tool is investigated with respect to workpiece surface roughness, cutting force and tool flank wear of the vision system. Backpropagation neural networks (BPNs) were used for detection of tool wear. The neural network consisted of three layers: input, hidden and output. The input vectors comprised of spindle rotational speed, feed rates, vision flank wear, and thrust force signals. The output was the tool wear state which was either usable or failure. Hard turning experiments with various spindle rotational speed and feed rates were carried out. The learning process was performed effectively by utilizing backpropagation. The detection of the abnormal states using BPNs achieved 96.4% reliability even when the spindle rotational speed and feedrate were changed.

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A Study of Tool Breakage Dection Using AE Sensor (AE(acoustic emission)센서를 이용한 공구파손검출에 관한 연구)

  • Lee, Jae-Jong;Song, Jun-Yeop;Park, Hwa-Yeong
    • 한국기계연구소 소보
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    • s.19
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    • pp.61-68
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    • 1989
  • As the system monitoring technology become required in order to improve the system performance and the productivity, we’ve studied to the detection for the tool wear and the tool breakage using AE sensors that is able to detection of generated high frequency stress pulse at cutting. The detection system is consist of a sensing part, a amplifier part, a signal processing part, and a analysis & output part. The moment (a rms and a kurtosis) of statistical method is used for analysis of AE singnal. The experiment are carried out in a CNC lathe. In this study, we achieved that the amplitude level of the AE signal and statistical moments was largely changed as the tool failure. The change rate of Kurtosis was especially large, but the change rate of the rms was small.

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Impact of PVD Coating Technology on HSS Tool (HSS공구와 PVD 코팅기술의 영향)

    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.899-904
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    • 2001
  • The impact of PVD coatings can be summed up in practical terms: this technology historically complements the best designed tool substrates to enhance cutting performance. PVD coatings are now incorporated in 25% of all HSS tools. The functionality is to extend the machining speed range, improve wear resistance at the cutting edge, and reduce friction at chip/tool contact areas to allow easier chip evacuation. These translate to a larger safe zone, as discussed in the failure mode diagram, for better productivity and higher reliability in machining operations of the customer. PVD coatings therefore represent an enabling technology that extends the application range of cutting tools in response to modern industrial needs. PVD coatings prolong the product life cycle of HSS tools and help this "mature" material to hold its territory against the advent of the newer hardmetal and ceramic tool materials. There is a lot of competitive life left particularly in PVD coated HSS endmills, drills, threading/tapping tools. PM HSS technology further increases the possibilities.ibilities.

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Development and testing of the hydrogen behavior tool for Falcon - HYPE

  • Piotr Konarski;Cedric Cozzo;Grigori Khvostov;Hakim Ferroukhi
    • Nuclear Engineering and Technology
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    • v.56 no.2
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    • pp.728-744
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    • 2024
  • The presence of hydrogen absorbed by zirconium-based cladding materials during reactor operation can trigger degradation mechanisms and endanger the rod integrity. Ensuring the durability of the rods in extended time-frames like dry storage requires anticipating hydrogen behavior using numerical modeling. In this context, the present paper describes a hydrogen post-processing tool for Falcon - HYPE, a PSI's in-house tool able to calculate hydrogen uptake, transport, thermochemistry, reorientation of hydrides and hydrogen-related failure criteria. The tool extracts all necessary data from a Falcon output file; therefore, it can be considered loosely coupled to Falcon. HYPE has been successfully validated against experimental data and applied to reactor operation and interim storage scenarios to present its capabilities.

Case Study of Electronic Fuel Injection Powertrain System FMEA Using Model-Based Fault Injection technique (모델 기반 결함 주입 기법을 이용한 Electronic Fuel Injection 전장 시스템 FMEA 사례연구)

  • Ye-ju Kim;Ye-won Na;Dong-min Lee;Ju-Young Kim;Jong-whoa Na
    • Journal of Advanced Navigation Technology
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    • v.27 no.4
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    • pp.436-446
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    • 2023
  • In the field of safety-critical systems, analyzing the effects of various failure factors (failure modes) is essential through Failure Mode and Effects Analysis (FMEA). However, with the increasing importance of software in systems, applying FMEA analysis to the design phase has become challenging. This paper proposes the use of Automatic FMEA, which can automatically perform FMEA using model-based design techniques, and presents a case study of FMEA for automotive engines. A comparison is made between the model-based Automatic FMEA analysis tool and existing FMEA tools. The study aims to demonstrate the performance of the Automatic FMEA analysis tool and propose future research plans.

Impact of rock microstructures on failure processes - Numerical study based on DIP technique

  • Yu, Qinglei;Zhu, Wancheng;Tang, Chun'an;Yang, Tianhong
    • Geomechanics and Engineering
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    • v.7 no.4
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    • pp.375-401
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    • 2014
  • It is generally accepted that material heterogeneity has a great influence on the deformation, strength, damage and failure modes of rock. This paper presents numerical simulation on rock failure process based on the characterization of rock heterogeneity by using a digital image processing (DIP) technique. The actual heterogeneity of rock at mesoscopic scale (characterized as minerals) is retrieved by using a vectorization transformation method based on the digital image of rock surface, and it is imported into a well-established numerical code Rock Failure Process Analysis (RFPA), in order to examine the effect of rock heterogeneity on the rock failure process. In this regard, the numerical model of rock could be built based on the actual characterization of the heterogeneity of rock at the meso-scale. Then, the images of granite are taken as an example to illustrate the implementation of DIP technique in simulating the rock failure process. Three numerical examples are presented to demonstrate the impact of actual rock heterogeneity due to spatial distribution of constituent mineral grains (e.g., feldspar, quartz and mica) on the macro-scale mechanical response, and the associated rock failure mechanism at the meso-scale level is clarified. The numerical results indicate that the shape and distribution of constituent mineral grains have a pronounced impact on stress distribution and concentration, which may further control the failure process of granite. The proposed method provides an efficient tool for studying the mechanical behaviors of heterogeneous rock and rock-like materials whose failure processes are strongly influenced by material heterogeneity.

Experimental and analytical investigation on seismic behavior of RC framed structure by pushover method

  • Sharma, Akanshu;Reddy, G.R.;Eligehausen, R.;Vaze, K.K.
    • Structural Engineering and Mechanics
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    • v.39 no.1
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    • pp.125-145
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    • 2011
  • Pushover analysis has gained significant popularity as an analytical tool for realistic determination of the inelastic behaviour of RC structures. Though significant work has been done to evaluate the demands realistically, the evaluation of capacity and realistic failure modes has taken a back seat. In order to throw light on the inelastic behaviour and capacity evaluation for the RC framed structures, a 3D Reinforced concrete frame structure was tested under monotonically increasing lateral pushover loads, in a parabolic pattern, till failure. The structure consisted of three storeys and had 2 bays along the two orthogonal directions. The structure was gradually pushed in small increments of load and the corresponding displacements were monitored continuously, leading to a pushover curve for the structure as a result of the test along with other relevant information such as strains on reinforcement bars at critical locations, failure modes etc. The major failure modes were observed as flexural failure of beams and columns, torsional failure of transverse beams and joint shear failure. The analysis of the structure was by considering all these failure modes. In order to have a comparison, the analysis was performed as three different cases. In one case, only the flexural hinges were modelled for critical locations in beams and columns; in second the torsional hinges for transverse beams were included in the analysis and in the third case, joint shear hinges were also included in the analysis. It is shown that modelling and capturing all the failure modes is practically possible and such an analysis can provide the realistic insight into the behaviour of the structure.

Development of Strain-gauge-type Rotational Tool Dynamometer and Verification of 3-axis Static Load (스트레인게이지 타입 회전형 공구동력계 개발과 3축 정적 하중 검증)

  • Lee, Dong-Seop;Kim, In-Su;Lee, Se-Han;Wang, Duck-Hyun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.9
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    • pp.72-80
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    • 2019
  • In this task, the tool dynamometer design and manufacture, and the Ansys S/W structural analysis program for tool attachment that satisfies the cutting force measurement requirements of the tool dynamometer system are used to determine the cutting force generated by metal cutting using 3-axis static structural analysis and the LabVIEW system. The cutting power in a cutting process using a milling tool for processing metals provides useful information for understanding the processing, optimization, tool status monitoring, and tool design. Thus, various methods of measuring cutting power have been proposed. The device consists of a strain-gauge-based sensor fitted to a new design force sensing element, which is then placed in a force reduction. The force-sensing element is designed as a symmetrical cross beam with four arms of a rectangular parallel line. Furthermore, data duplication is eliminated by the appropriate setting the strain gauge attachment position and the construction of a suitable Wheatstone full-bridge circuit. This device is intended for use with rotating spindles such as milling tools. Verification and machining tests were performed to determine the static and dynamic characteristics of the tool dynamometer. The verification tests were performed by analyzing the difference between strain data measured by weight and that derived by theoretical calculations. Processing test was performed by attaching a tool dynamometer to the MCT to analyze data generated by the measuring equipment during machining. To maintain high productivity and precision, the system monitors and suppresses process disturbances such as chatter vibration, imbalances, overload, collision, forced vibration due to tool failure, and excessive tool wear; additionally, a tool dynamometer with a high signal-to-noise ratio is provided.

Optimum Tool Design in a Multi-stage Rectangular Cup Drawing and Ironing Process with the Large Aspect Ratio by the Finite Element Analysis (유한요소해석을 이용한 세장비가 큰 직사각컵 다단계 디프 드로잉-아이어닝 공정의 최적 금형설계)

  • Kim, Se-Ho;Kim, Seung-Ho;Huh, Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.6
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    • pp.1077-1084
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    • 2002
  • Optimum tool design is carried out fur a multi-stage rectangular cup deep-drawing and ironing process with the large aspect ratio. Finite element simulation is carried out to investigate deformation mechanisms with the initial design made by an expert. The analysis considers the deep drawing process with ironing for the thickness control in the cup wall. The analysis reveals that the difference of the drawing ratio within the cross section and the irregular contact condition produce non-uniform metal flow to cause wrinkling and severe extension. For remedy, the modification guideline is proposed in the design of the tool and the process. Analysis results confirm that the modified tool design not only improves the quality of a deep-drawn product but also reduces the possibility of failure. The numerical result shows fair coincidence with the experimental one. After tryouts of the tool shape, the rectangular cup has been produced in the transfer press.

Lessons Learned from the Failure Cases in Social Media Marketing (소셜미디어 마케팅 실패사례 분석을 통한 소셜미디어 마케팅 전략 연구)

  • Cho, Eun-Young;Park, Jin-Won;Kim, Hee-Woong
    • Knowledge Management Research
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    • v.16 no.2
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    • pp.91-111
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    • 2015
  • Social media marketing has gained attention from marketers due to the growing number of social media users. Marketers around the globe have a serious concern over how to utilize social media as a successful marketing tool. Many of them show a lack of understanding of the essential feature of social media and effective social media marketing strategies, which brings about a higher chance of social media marketing failures. Analyzing the failure cases of social media marketing is vital because it provides rich insights for marketing experts who have difficulty in developing effective social media marketing strategies. Therefore, this study conducted multiple case studies by selecting five failure cases of social media marketing which we defined as paradigmatic social media marketing failures which happened in the last five years in South Korea. From the case studies, we derived five successful social media marketing strategies. This study has a theoretical implication because it is the first to suggest effective social media marketing strategies based on the analysis on social media marketing failure cases. It also has a practical implication since it proposes specific social media marketing strategies which can help facilitate successful social media marketing.