• 한국안전학회지
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• 제16권1호
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• pp.88-93
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• 2001

본 연구에서는 복합소재인 GFRP(Glass Fiber Reinforced Polyester)의 2차원 절삭공정에서 절삭 메커니즘과 소재의 신뢰도 및 안전성과 밀접한 관련이 있는 표면정도를 중심으로 한 공정의 특성화를 시도하고, 주파수 분석에 관하여도 논의한다. 구체적으로는, 공정중 발생하는 절삭력 신호를 AR(Autoregressive) 모델링하여 해석에 사용한다. 특히, 특징추출과정을 통해 AR계수로 이루어진 패턴벡터 중 다양한 절삭 메카니즘에 민감한 계수만 선택할 수 있다. 이들 계수와 절삭 메커니즘과의 실험적 관계를 설정함으로써 섬유경사각(Fiber orientation angle), 절삭 변수 그리고 공구형상이 절삭 메커니즘에 미치는 영향을 평가하였다.

• Journal of Mechanical Science and Technology
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• 제15권3호
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• pp.351-356
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• 2001

In the surface grinding operations, the grinding fluid cannot be supplied sufficiently in the cutting zone. Temperature generated in the cutting zone increases rapidly and causes thermal damage such as burning on the surface of a workpiece. To reduce thermal damage, the intermittent grinding wheels, which have an excellent cooling effect, have been applied. This paper describes machining characteristics by using intermittent grinding wheels. The grinding force of the intermittent wheels has been simulated by the SIMULAB, which is a program for simulating dynamic systems. Using the intermittent grinding wheels, the characteristics of grinding force, temperature, surface roughness, and geometric error have been evaluated experimently.

• 대한기계학회논문집A
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• 제41권5호
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• pp.353-359
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• 2017

금형 산업과 다양한 산업에서 사용되고 있는 CNC공작기계는 최근 첨단 제품이나 신제품 설계에서 공정의 증가로 생산 품질과 작업자의 안전성 측면이 중요해지고 있으며, 생산제품의 품질을 균일하게 하고 재현성을 향상시키기 위한 최적 절삭 조건 선정 연구가 진행되어 왔다. 본 연구에서는 공구의 기하학적 모델링을 진행하고 생산 제품의 재현성 향상을 위한 조건 선정 선행 연구와 기존의 공구 인서트를 바탕으로 Solidworks 설계 프로그램을 이용하여 공구 인서트를 모델링하였다. 모델링 데이터를 바탕으로 AdvantEdge를 사용하여 절삭 공정에서 절삭력, 공구 응력, 그리고 온도의 변화에 대한 해석을 진행하였다.

• Structural Engineering and Mechanics
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• 제84권1호
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• pp.17-33
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• 2022

An experimental study is carried out to investigate the performance of the cutting tool regarding the insert wear, surface roughness, cutting forces, cutting power and material removal rate of three coated carbides GC2015 (TiCN-Al₂O₃-TiN), GC4215 (Al₂O₃-Ti(C,N)) and GC1015 (TiN) during the dry turning of AISI4140 steel. For this purpose, a Taguchi design (L₉) was adopted for the planning of the experiments, the effects of cutting parameters on the surface roughness (R_a), tangential cutting force (F_z), the cutting power (P_c) and the material removal rate (MRR) were studied using analysis of variance (ANOVA), the response surface methodology (RSM) was used for mathematical modeling, with which linear mathematical models were developed for forecasting of R_a, F_z, P_c and MRR as a function of cutting parameters (V_c, f, and a_p). Then, Multi-Objective Ant Lion Optimizer (MOALO) has been implemented for multi-objective optimization which allows manufacturers to enhance the production performances of the machined parts. Furthermore, in order to characterize and quantify the flank wear of the tested tools, some machining experiments were performed for 5 minutes of turning under a depth of 0.5 mm, a feed rate of 0.08 mm/rev, and a cutting speed of 350 m/min. The wear results led to a ratio (V_B-GC4215/V_B-GC2015) of 2.03 and (V_B-GC1015/V_B-GC2015) of 4.43, thus demonstrating the efficiency of the cutting insert GC2015. Moreover, SEM analysis shows the main wear mechanisms represented by abrasion, adhesion and chipping.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2008년도 춘계학술발표논문집
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• pp.306-308
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• 2008

본 논문은 정면 밀링 가공에서의 절삭력 예측을 위한 수학적 모델을 설정하고 컴퓨터 시뮬레이션을 수행하였다. 실험으로 얻은 절삭력 데이터를 이용하여 비절삭 저항을 모델링하였고 컴퓨터 시뮬레이션을 통해 절삭력을 예측하였다. 예측된 절삭력은 실제 실험을 통해 얻은 절삭력과 비교하여 본 모델의 타당성을 검증하였다.

• 한국기계가공학회지
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• 제7권3호
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• pp.96-102
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• 2008

In order to design establish automation or optimization of the machining process, predictions of the forces in machining are often needed. In this paper, a theoretical model in face milling is presented based on Oxley's predictive machining theory, where the cutting forces are predicted from input data of fundamental work material properties, tool geometry and cutting conditions without any preliminary cutting experiment. A simulation system for the cutting forces in face milling is developed using the model. Milling experimental tests are conducted to verify the model and the predictive results are compared and discussed with the experimental results.

• 한국공작기계학회논문집
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• 제17권4호
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• pp.95-103
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• 2008

Diamond core drills are applied to drill difficult-to-cut materials. This paper proposes basic understanding of ceramic drilling mechanics and characteristics of main factors affecting tool life, tool wear, cutting force, and chipping thickness. In contrast to conventional drilling, the core drilling process make deep grooves on the workpiece. One difficulty of it is the evacuation of chips from the drilled groove. As the drilling depth increases, an increased amount of chips tend to cluster together and clog the groove. Eventually severe wear develops and diamond grits are separated from the drill body. To relieve the clogging problem and to evacuate chips from the groove easily, the helical drilling process is applied for the core drilling process. To analyze drilling characteristics and derive optimal drilling conditions, tool life, tool wear, cutting force, and chipping thickness are quantified through the monitoring system and the Taguchi method. Mathematical models for the tool life and chipping thickness are derived from the response surface method. Optimal drilling database has been constructed through the experimental models.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1799-1802
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• 2003

The commercial success of a new product is influenced by the time to market. Shorter product leadtimes are of importance in a competitive market. This can be achieved only if the product development process can be realized in a relatively small time period. New cutting inserts are developed by a time consuming trial and error process guided by empirical knowledge of the mechanical cutting process. The effect of previous cutting on chip formation and the surface residual stresses has been studied. The chip formation is not affected much. There is only a minor influence from the residual stress on the surface from tile first cutting on the second pass chip formation. Thus, it is deemed to be sufficient to simulate only the first pass. The influence of the cutting speed and feed on the residual stresses has been computed and verified by the experiments. It is shown that the state of residual stresses in the workpiece increases with the cutting speed. This paper presents experimental results which can be used for evaluating computational models to assure robust solutions. The general finite element code ABAQUS/Standard has been used in the simulations. A quasi-static simulation with adiabatic heating was performed. The path for separating the chip from the workpiece is predetermined. The agreement between measurements and calculation is good considering the simplifications introduced.

• Structural Engineering and Mechanics
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• 제86권1호
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• pp.119-137
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• 2023

The purpose of this research is to assess the performance of CBN and ceramic tools during the dry turning of gray cast iron EN GJL-350. During the turning operation, the variable machining parameters are cutting speed, feed rate, depth of cut and type of the cutting material. This contribution consists of two sections, the first one deals with the performance evaluation of four materials in terms of evolution of flank wear, surface roughness (2D and 3D) and cutting forces. The focus of the second section is on statistical analysis, followed by modeling and optimization. The experiments are conducted according to the Taguchi design L₃₂ and based on ANOVA approach to quantify the impact of input factors on the output parameters, namely, the surface roughness (Ra), the cutting force (Fz), the cutting power (Pc), specific cutting energy (Ecs). The RSM method was used to create prediction models of several technical factors (Ra, Fz, Pc, Ecs and MRR). Subsequently, the desirability function approach was used to achieve a multi-objective optimization that encompasses the output parameters simultaneously. The aim is to obtain optimal cutting regimes, following several cases of optimization often encountered in industry. The results found show that the CBN tool is the most efficient cutting material compared to the three ceramics. The optimal combination for the first case where the importance is the same for the different outputs is Vc=660 m/min, f=0.116 mm/rev, ap=0.232 mm and the material CBN. The optimization results have been verified by carrying out confirmation tests.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.69-73
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• 1996

Tool wear monitoring is very important aspect in metal cutting because tool wear effects quarity and precision of workpiece, tool life etc. In this study we detected force signal through tool dynamometer in turning and using it we conducted 6th AR modeling and fractal analysis. Finally the back-propagation model of the neural network is utilized to monitor tool wear and features are extracted through AR model and fractal analysis.