• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 추계학술대회 논문집
• /
• pp.810-813
• /
• 2000

Burr makes trobles on manufacturing process due to deburring cost, quality of products and productivity. This paper described the results of experimental study on the influence of the cutting parameters on the formation of exit burrs in face milling. The cutting parameters were investigated changing exit angle, rake nagle , lead angle in tool geometry as well as feed per tooth. Also we carried out experimets on several materials. Using the result of experimental study, burr types are classified according to appearance and formation mechanism in exit burr and we are considered the burr formation in each type of burr.

• 한국정밀공학회지
• /
• 제19권12호
• /
• pp.86-92
• /
• 2002

This paper presents a new model of NC verification in NC milling using z-map. The model can describe the motion of machine tool like a real machine effectively. The model uses x, y, and z directional feed rate as well as cutting data for modeling Z-map of workpiece. The model verifies the over-cut, the under-cut and the surface topography using NC codes and cutting conditions. To investigate the performance of the model, simulation study was carried out. As the results, the model gave the geometry accuracy of workpiece, the surface topography, and the chip loads.

• 한국공작기계학회논문집
• /
• 제10권2호
• /
• pp.124-129
• /
• 2001

The level surface approach for following flame front propagating in a premixed medium is adapted to incorporate the flameholding scheme. This allows one to follow the flameholding scheme. This allows one to follow the motion of an N-1 dimensional surface in N space dimensions. The flame speed may be an arbitrary function of flame geometry and the front is passively advected by an underlying flow field. This algorithm provides and accurate calculation of the flame curvature which may be needed for the flame propagation computation and thereby the estimation of curvature-dependent flame speeds. A numerical demonstration of this method-ology is applied to simulate the excursion of an anchored V-flame and locate the final equilibrium position.

• 한국공작기계학회논문집
• /
• 제13권6호
• /
• pp.17-22
• /
• 2004

A study for investigating the effects of the cutting conditions (radial depth of cut feed per tooth) and the number of tooth on the side wall of prismatically milled workpiece is described. This study is available not only for understanding the geometrical characteristics of the end milled side wall but also for finding the optimal cutting conditions. In this work, the side wall geometry was characterized by the straightness and the location of maximum peak point. Through this study, it was revealed that the geometrical characteristics of the end milled side wall are strongly related to the material removal per tooth and the number of tooth.

• 한국공작기계학회논문집
• /
• 제10권1호
• /
• pp.78-87
• /
• 2001

This paper deals with the study on the cutting characteristics in ball-end milling process. First of all, the effects of the geometric cutting conditions such as the cutting speed, feedrates and the path interval on the surface integrity were evaluat-ed by the analytical and the experimental approaches. Secondly, the cutting mechanism model was developed to predict the cutting force accurately. It is possible for the proposed model to predict the shape error, estimate system stability and build the reliable adaptive control system. A large amount of experimental set are performed to show the validities of the proposed theories and to investigate the effect of cutting geometry such as rubbing effects, burr effects and etc.

• 한국공작기계학회논문집
• /
• 제10권2호
• /
• pp.64-72
• /
• 2001

Weld line is one of serious troubles which are observed in a plastic part manufactured by a injection molding process. This is caused by many process factors, which are molding pressure, temperature, velocity, location of a injection gate, mold geometry and material properties. investigation on the effects of these process factors to the appearance of a weld line was carried out using a finite element method. Filling and packing analyses were carried out by modifying both the configuration of the injection gates and cavity thickness. Proper locations of the injection gates could be determined by considering molding pressure, temperature, velocity and frozen layer, and whereby the weld line was controled. In order to make a weak appearance of the weld line, flow velocity and flow front in a cavity were also investigated by modifying a cavity thickness. As a result, flow front was extended around the corner in the cavity by changing the flow velocity and hence the appearance of the weld line was much weakened.

• 한국공작기계학회논문집
• /
• 제17권1호
• /
• pp.150-157
• /
• 2008

Bellows are commonly used in piping systems to absorb expansion and contraction in order to reduce stress. Unlike most piping components, bellows consist of a thin-walled shell of revolution with a corrugated meridian, in order to provide the flexibility needed to absorb mechanical movements. It is a composite shell structure consisting of at least one toroidal shell, an annular plate or conical shell. It is difficult to analyze the behavior of bellows because of its complex geometry. Simplified formulas for variable mechanical behaviors of bellows are provided by a standard called EJMA. An automatic design software for bellows is programming by using VBA(Visual Basic for Application) based on EJMA. Bellows engineers can effectively make a decision for bellows geometries because this software provides graphically design results in its post-processor. Bellows design software is expected to give quite a good guidance to practical design. The characteristics of bellows are also investigated through the automatic design process in bellows design software.

• 한국공작기계학회논문집
• /
• 제17권1호
• /
• pp.98-105
• /
• 2008

In this paper, the system for monitoring process of aluminum laser welding was developed using the light signal emitted from the plasma which comes from interaction between material and laser. Photodiode for monitoring system was selected based on the spectrum analysis of light from plasma and keyhole. Behavior of plasma and keyhole was analyzed through the sensor signals. Value of sensor signal represented the light intensity and fluctuation of signal indicated the stability of plasma and keyhole. For the relation between welding condition and sensor signals, the input power and weld geometry greatly effected on the average of each sensor signals. Using the feature values of signals, estimation model for tensile strength of weld was formulated with neural network algorithm. Performance of this model was verified through coefficient of determination and average error rate.

• 한국공작기계학회논문집
• /
• 제16권4호
• /
• pp.29-35
• /
• 2007

The main objective of this paper is to propose the optimal design method of forging process using genetic algorithm. Design optimization of forging process was doing about one stage and multi stage. The objective function is considered the filling of die. The chosen design variables are die geometry in multi stage and initial billet shape in one stage. We performed FE analysis to simulated forging process. The optimized preform and initial billet shape was obtained by genetic algorithm and FE analysis. To show the efficiency of GA method in forging problem are solved and compared with published results.

• 청정기술
• /
• 제22권1호
• /
• pp.45-52
• /
• 2016

This study reports on the modeling and simulation of heat transfer in packaging boxes used for vaccine shipping. Both water and n-tetradecane are used as primary insulation materials inside a multi-slab system. The one-dimensional model, which is a spherical model using a radius equivalent to the rectangular geometry of container, is applied in this study. N-tetradecane with low thermal diffusivity and proper phase transition temperature exhibits higher heat transfer resistance during both heating and cooling processes compared to water. Thus, n-tetradecane is a better candidate as an insulating material for packaging containers for vaccine shipping. Furthermore, the developed method can also become a rapid and economic tool for screening appropriate phase change materials used as insulation materials with suitable properties in logistics applications.